�.� Mosby
An Alliliate of Elsevier Scicnce
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63 1 �6
MERRILL'S ATLAS OF RADIOGRAPHIC POSI TIONS AND RADIOLOGIC PROCEDURES. ED Copyri�ht
10
ISBN (Sell (Volume One)
© 2003. Mosby. Inc. All right� reserved.
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Book Number (Set) 0-323-01604-9 (Volume I) 0-323-01606-5
Publisher: Andrew Allen E.tt'cutil·,' Editor: Jeanne Wilke DI'I'I'/oplIIl'llIa/ Editors: Jennifer Gcnen Moorhead. Carolyn Kruse Publishil/g Sen'ices Mmltlgt'r: Patricia Tannian
S"I/ior Projconway JJ, Cowell HR: Tarsal coalition: clinical significance and roentgenographic demonstration, Radiology 92:799, 1 969.
Tibia Fibula
Calcaneus
Talus
Tibia
Fibula
Talus ���=:-:---t Calcaneus
Fig. 6-78 AP projection after treatment (same patient as in Fig. 6-77).
Fig. 6-79 Lateral projection after treatment (same patient as in Fig. 6-76),
277
Foot Congenital Clubfoot AXIAL PROJECTION Dorsoplantar KANDEL M ETHODl
Kande l ' recommended the inclu ion of a dorsoplantar axial projection in the exam ination of the patient with a cl ubfoot (Fig. 6-80). For this method the infant is held i n a vertical or a bending-forward position. The plantar surface of the foot should rest on the lR, although a moderate elevation of the heel is acceptable when the equinus deformity is well marked. The central ray is directed 40 degrees anteriorly through the lower leg, as for the usual dorsoplan tar projection of the calcaneus (Fig. 6-8 1 ).
Freiberger, Hersh, and Harrison ' stated that sustentaculum talar joint fusion can not be assumed on one projection, be cause the central ray may not have been paral lel with the articular surfaces. They recommended that three radiographs be obtained with varyi ng central ray angula tions (35, 45, and 55 degrees). 'Freiberger RH, Hersh A, Harrison MO: Roentgen examination of the deformed foot, Semill Roell/gellol 5 : 34 1 , 1 970 .
' Kandel B : The suroplantar projection in the con genital clubfoot of the infant, Acta Or/hop Scand 22: 1 6 1 , 1 952 .
: .J/' .' , .. • • • • • • • • • •
•
/4[)" ;
Fig. 6-80 Axial foot (dorsoplantar): Kandel method.
Fig. 6·8 1 Axial foot (dorsoplantar): Kandel method.
278
Calcaneus
.. AXIAL PROJECTION Plantodorsal Image receptor: 8 x 1 0 inch ( 1 8 X 24 cm) Position of patient • Place the patient in the supine or seated position with the legs fully extended. Position of part • Place the IR under the patient's ankle,
centered to the midl ine of the ankle (Fig . 6-82 and 6-83). • Place a long strip of gauze around the bal l of the foot . Have the patient grasp the gauze to hold the ankle in right angle dorsi flexion. • If the patient's ankles cannot be flexed enough to place the plantar surface of the foot perpendicular to the IR, elevate the leg on sandbags to obtain the cor rect position. • Shield gonads. Central ray • Directed to the midpoint of the I R at a cephal ic angle of 40 degrees to the long axis of the foot. The central ray enters the ba e of the third metatar al. Structures shown The resulting image shows an axial pro jection of the calcaneus (Fig. 6-84).
Fig. 6-82 Axial (plantodorsal) calcaneus.
C.R,
.�
EVALUATION CRITERIA
The fol lowing hould be clearly demon strated: • Calcaneus and subtalar joint. • No rotation of the calcaneus-the first or fifth metatar als not projected to the sides of the foot. • Anterior portion of the calcaneus with out excessive density over the posterior portion. Otherwise two i mages may be needed for the two regions of thickness.
Fig. 6-83 Axial (plantodorsal) calcaneus,
Calcaneocuboid joint Sustentaculum tali
Calcaneus
Fig. 6-84 Axial (plantodorsal) calcaneus, 279
Calcaneus
AXIAL PROJECTION Dorsoplantar Image receptor: 8 x 1 0 inch ( 1 8 x 24 cm) Position of patient • Place the patient in the prone position.
Fig. 6-85 Axial (dorsoplantar) calcaneus.
280
Position of part • Elevate the patient's ankle on andbags. • Adj ust the height and position of the sandbags under the ankle in such a way that the patient can dorsiflex the ankle enough to place the long axis of the foot perpendicular to the tabletop. Place the IR against the plantar urface of the foot, and upport it in po ition with andbags or a portable IR holder (Figs. 6-85 and 6-86). • Shield gonads. •
Fig. 6-86 Axial (dorsoplantar) calcaneus.
Calcaneus
Central ray • Directed to the midpoint of the I R at a caudal angle of 40 degrees to the long axis of the foot. The central ray enters the dorsal surface of the ankle joint. Structures shown The re ulting i mage shows an axial pro jection of the calcaneus and the subtalar joint (Fig. 6-87). EVALUATION CRITERIA
The following should be clearly demon strated: • Calcaneus and the subtalar joint. • Sustentaculum tal i . • Calcaneus not rotated-the fi rst o r fifth metatar als not projected to the sides of the foot.
•
Anterior portion of the calcaneus with out excessive density over posterior portion. Otherwise, two images may be needed for the two regions of thickness.
WEIGHT-BEARING · COALITION M ETHOD ! " This method, described by Lilienfeld ' (cit. Holzknecht), has come into use for the demonstration of calcaneotalar coalition. 24 For this reason it has been called the "coali tion position." ' Lilienfeld
L: Anordllullg der llonnaJisierten Rontgenaujnahmen des menschlichen Korpers, ed 4, Berlin, 1 927, Urban & Schwarzenberg. 'Harris R l , Beam T: Etiology of peroneal spastic flat foot. J Bone Joint Surg 30B:624, 1 948. 'Coventry MB: Flatfoot with special consideration of tarsal coalition, Minn Med 33: 1 09 1 , 1 950. 'Vaughan WH, Segal G: Tarsal coalition, with spe cial reference to roentgenographic interpretation, Radiology 60:855, 1 953.
Position of patient • Place the patient in the standing-upright
position. Position of part • Center the I R to the long axis of the cal
•
caneus, with the posterior surface of the heel at the edge of the I R . To prevent uperimposition o f the leg shadow, have the patient place the op posite foot one step forward (Fig. 6-88).
Central ray • Angled exactly 45 degrees anteriorly and directed through the posterior sur face of the flexed ankle to a point on the plantar surface at the level of the base of the fifth metatar al
Trochlea Sustentaculum tali Lateral process Tuberosity
Fig. 6-87 Axial (dorsoplantar) calcaneus.
Fig. 6-88 Weight-bearing ' coalition method:
281
Calcaneus
.. LATERAL PROJECTION Mediolateral Image receptor: 8 x 1 0 inch ( 1 8 X 24 cm) Position of patient Have the supine patient turn toward the affected side until the leg is approxi mately lateral. A support may be placed under the knee.
Position of part Adjust the calcaneus to the center of the IR. Adjust the I R so that the long axis is parallel with the plantar surface of the heel (Fig. 6-89). Shield gonads.
•
•
•
•
Central ray
EVALUATION CRITERIA
The fol lowing should be clearly demon strated: • No rotation of the calcaneu • Density of the sustentaculum tali, lat eral tuberosity, and soft tissue • Sinus tarsi • Ankle joint and adj acent tarsals
• Perpendicular to the calcaneus. Center
about I inch (2.5 cm) distal to the me dial malleol us. This will place the CR at the subtalar joint.
Structures shown The resulting radiograph shows the ankle joint and the calcaneu in lateral profile (Fig. 6-90).
Tiblotalar Joint
Talus
Navicular
Sinus tarsi
Sustentaculum tali Tuberosity
Fig. 6-89 Lateral calcaneus.
282
Fig. 6-90 Lateral calcaneus.
Calcaneus
LATEROMEDIAL OBLIQUE PROJECTION WEIGHT-BEARING M ETHOD
Image receptor: 8 x 10 inch ( 1 8 X 24 cm) Position of patient Have the patient stand with the affected heel centered toward the lateral border of the IR (Fig. 6-9 1 ). A mobile radiographic unit may assist in this examination.
•
•
Position of part Adjust the patient's leg to ensure that it is exactly perpendicular. Center the calcaneus so that it will be projected to the center of the J R . Center the lateral mal leolus t o the mid line axis of the JR. Shield gonads.
•
•
•
•
Central ray Directed medially at a caudal angle of 45 degrees to enter the lateral malleolus. •
Structures shown The re ulting image shows the calcaneal tubero ity and is useful in diagnosing stress fractures of the calcaneu or tuberosity ( Fig. 6-92).
Fig. 6-9 1 Weight-bearing lateromedial oblique calcaneus.
EVALUATION CRITERIA
Navicular
The follow ing should be clearly demon strated: • Calcaneal tuberosity • Sinus tarsi • Cuboid
Sinus tarsi
Calcaneus Cuboid Tuberosity
Fig. 6-92 Weight-bearing lateromedial oblique calcaneus.
283
Subtalar Joint
PA AXIAL OBLIQUE PROJECTION Lateral rotation The calcaneus has three articular surfaces: anterior, middle, and posterior. These sur faces are located on the superior calca neu and articulate with the inferior talus. The articulations form the subtalar (talo calcaneal ) joint ( ee Fig. 6- 1 1 ). This pro jection best demonstrates the middle and posterior articulations. Image receptor: 8 x 1 0 inch ( 1 8 X 24 cm)
Position of patient Have the patient lie on the affected side in the lateral position. Flex the uppermost knee to a comfort able position, and support it on and bags to prevent too much forward rota tion of the body (Fig. 6-93).
•
•
•
Position of part Ask the patient to extend the affected limb. Rol l the Limb lightly forward from the lateral position. Center the IR 1 to 1 1; inches (2.5 to 3.8 cm) distal to the ankle joint and ad just it so that its midline is parallel with the long axis of the leg.
•
•
•
•
Adju t the obliquity of the foot so that the heel is elevated about 1 1; inches (3.8 cm) from the exact lateral position. The bal l of the foot (the metatarsopha langeal area) will be angled forward ap proximately 25 degrees. Shield gonads.
Central ray Directed to the ankle joint at a double an gIe of 5 degrees anterior and 23 degrees caudal.
•
NOTE: Some x-ray tube may not double angle.
Structures shown The resulting i mage shows the middle and po terior articulation of the subtalar joint and give an "end-on" image of the inu tarsi and an unobstructed projection of the lateral malleolus (Fig. 6-94). EVALUATION CRITERIA
The following should be clearly demon strated: • Open subtalar (talocalcaneal) joint ar ticulations • Sinus tarsi • Lateral malleolus seen in profile
Fig. 6-93 PA axial oblique subtalar joint. lateral rotation.
Tibia Lateral malleolus Talus
Sinus tarsi
Navicular
Talonavicular Joint
Subtalar (talocalcaneal) joint
Calcaneus
Fig. 6-94 PA axial oblique subtalar joint.
284
Subtalar Joint
AP AXIAL OBLIQUE PROJECTION BRODEN METHOD! Medial Rotation Broden ! recommended the lateromedial and mediolateral right-angle oblique pro jection for demonstration of the posterior articular facet of the calcaneus to deter mine the presence of joint involvement in cases of comminuted fracture. Image receptor: 8 x 1 0 inch ( 1 8 X 24 cm)
Position of patient
o Place the patient in the supine position. o Adjust a small sandbag under each knee. Position of part
o Place the IR under the patient's lower leg and heel with its midline parallel with and centered to the leg. o Adjust the I R so that the lower edge is about 1 inch (2.5 cm) distal to the plan tar surface of the heel.
o Loop a strip of bandage around the ball of the foot. Have the patient grasp the ends of the bandage and dorsiflex the foot enough to obtain right-angle flex ion at the ankle joint. Ask the patient to maintain the flexion for the exposure. o With patient's ankle joint maintained in right-angle flexion, rotate the leg and foot 45 degrees medially, and rest the foot against a 45-degree foam wedge (Fig. 6-95 ). o Shield gonads.
'Broden B: Roentgen examination of the subtaloid joint in fractures of the calcaneus. Acta Radial 3 1 :85. 1 949.
1 0°
20°
30°
40°
Fig. 6-95 AP axial oblique subtalar joint, medial rotation.
285
Subtalar Joint
Central ray Angled cephalad at 40, 30, 20, and 1 0 degrees, respectively. Four separate im ages are obtained For each i mage, direct the central ray to a point 2 or 3 cm caudoanteriorly to the lateral malleolus, to the midpoint of an imagi nary line extending between the most promi nent point of the lateral malleol us and the base of the fifth metatarsal (Figs. 6-96 to 6-99). •
•
Structures shown The anterior portion of the posterior facet is shown best in the 40-degree projection. The 1 0-degree projection shows the poste rior portion. The articulation between the talus and sustentaculum tali ( middle facet) i usually shown best in one of the inter mediate projections. EVALUATION CRITERIA Fig. 6-96 AP axial oblique subtalar joint with angulation of 40 degrees.
The fol lowing should be clearly demon strated : • Anterior and posterior portions of the posterior subtalar joint
Fig. 6-97 AP axial oblique subtalar joint with angulation of 30 degrees.
Talus Subtalar joint �__-
Calcaneus
Fig. 6-98 AP axial oblique subtalar joint with angulation of 20 degrees.
286
Fig. 6-99 AP axial oblique subtalar
joint with angulation of 10 degrees.
Subtalar Joint
AP AXIAL OBLIQUE PROJECTION BRODEN METHOD Lateral rotation
Central ray Directed to a point 2 cm distal and 2 cm anterior to the medial mal leolus, at a cephalic angle of 1 5 degrees for the first exposure (Fig. 6- 1 0 I ). Two or three images may be made with a 3- or 4-degree difference in central ray angulation ( Fig. 6- 1 02).
•
Image receptor: 8 x 1 0 inch ( 1 8 x 24 cm) Position of patient Place the patient in the supine position. Adjust a small sandbag under each knee.
Structures shown The posterior facet of the calcaneus is shown in profi le. The articulation between the talus and sustentaculum tali is usually shown.
•
EVALUATION CRITERIA
The fol lowing should be clearly demon strated: • Po terior portion of the subtalar joint
•
•
Position of part With the patient's ankle joint held in right-angle flexion, rotate the leg and foot 45 degrees laterally ( Fig. 6- 1 00). The foot may rest against a 45-degree foam wedge. Shield gonads.
•
•
Fig. 6- 1 00
AP axial oblique subtalar joint. lateral rotation.
Tibia Talus __I
Subtalar Joint Calcaneus
Fig.
6- 1 01 AP axial oblique subtalar joint with an
gulation of 1 5 degrees.
Fig. 6- 1 02 AP axial oblique subtalar joint with angulation of 1 8 degrees.
287
Subtalar Joint
LATEROMEDIAl OBLIQUE PROJECTION ISHERWOOD M ETHOD1 Medial rotation foot Isherwood 1 devised a method for each of the three separate articulations of the sub talar joint: ( I ) a medial rotation foot posi tion for the demonstration of the anterior talar articular surface, (2) a medial rota tion ankle position for the middle talar ar ticular urface, and (3) a lateral rotation ankle position for the posterior talar artic ular surface. Feistl later described a simi l ar position. Image receptor: 8 x 1 0 inch ( 1 8 x 24 cm) for each position
Position of part • With the medial border of the foot re t
•
•
•
•
ing on the I R, place a 45-degree foam wedge under the elevated leg. Adj ust the leg so that i ts long axis is in the same plane as the central ray. Adj ust the foot to be at a right angle. Place a support under the knee (Fig. 6- 1 03). Shield gonads.
Central ray Perpendicular to a point I inch (2.5 cm) distal and I inch (2.5 cm) anterior to the lateral malleolus
Structures shown The resulting i mage shows the anterior subtalar articular surface and an oblique projection of the tar als (Fig. 6- 1 04). The Feist-Mankin method produces a similar i mage representation. EVALUATION CRITERIA
The fol lowing hould be clearly demon strated: • Anterior talar articular surface
•
Position of patient Place the patient in a semisupine or eated position, turned away from the ide being examined Ask the patient to flex the knee enough to place the ankle joint in nearly right angle flexion and then to lean the leg and foot medially.
•
' Isherwood I: A radiological approach to the subtalar joint, J BOlle Joilll SLlrg 438:566, 1 96 1 . 'Feist JH, Mankin HJ: The tarsus: basic relationships and motions in the adult and definition of optimal re cumbent oblique projection, Radiology 79:250, 1 962.
Fig. 6- 1 03 Lateromedial oblique subtalar joint medial rotation: Isherwood method.
Tibia Anteriar talar articular surface
�!II!Pr;::�� Cuboid
Calcaneus
Fig. 6- 1 04 Lateromedial oblique subtalar joint demonstrating anterior articular surface: Isherwood method.
288
Subtalar Joint
AP AXIAL OBLIQUE PROJECTION ISHERWOOD METHOD Medial rotation ankle
Central ray Directed to a point I inch (2.5 cm) di tal and I inch (2.5 cm) anterior to the l ateral malleolus at an angle of 1 0 degrees cephalad. •
Image receptor: 8 x l O i n ( 1 8 x 24 cm)
Structures shown The resulting image shows the middle ar ticulation of the subtalar joint and an "end-on" projection of the sinus tar i (Fig. 6- 1 06). EVALUATION CRITERIA
Position of patient Have the patient assume a seated po i tion on the radiographic table and turn with body weight resting on the flexed hip and thigh of the unaffected side. If a semi lateral recumbent position is more comfortable, adj ust the patient ac cordi ngly.
The following should be clearly demon strated: • M iddle (subtalar) articulation • Open sinus tarsi
•
•
Position of part Ask the patient to rotate the leg and foot medially enough to rest the side of the foot and affected ankle on an optional 30-degree foam wedge (Fig. 6- 1 05). Place a upport under the knee. I f the patient is recumbent, place another un der the greater trochanter Dorsiflex the foot, then invert it if pos sible, and have the patient maintain the position by pulling on a strip of 2- or 3i nch (5- to 7.6-cm) bandage looped around the ball of the foot. Shield gonads.
•
•
•
•
Fig. 6- 1 05 AP axial oblique subtolar joint. medial rotation: Isherwood method.
Talus Posterior subtalar articulation
Sinus tarsi Middle subtalar articulation
:::!!�:--;:====---':-�---:---l Calcaneus
Fig. 6- 1 06 AP axial oblique subtalar joint: Isherwood method.
289
Subtalar Joint
AP AXIAL OBLIQUE PROJECTION ISHERWOOD METHOD Lateral rotation ankle Image receptor: 8 x 1 0 inch ( 1 8 X 24 cm) Position of patient Place the patient in the supine or seated position.
•
Position of part • Ask the patient to rotate the leg and foot laterally until the side of the foot and ankle rests against an optional 30-de gree foam wedge. • Dorsiflex the foot, evert it if possible, and have the patient maintain the posi tion by pulling on a broad bandage looped around the ball of the foot (Fig. 6- 1 07). • Shield gonads.
Central ray • Directed to a point I inch (2.5 cm) dis tal to the medial malleolus at an angle of 1 0 degrees cephalad Structures shown The resulting i mage shows the posterior articulation of the ubtalar joint in profile (Fig. 6- 1 08). EVALUATION CRITERIA
The fol lowing should be clearly demon strated: • Posterior subtalar articulation
Fig. 6- 1 07 AP axial oblique subtalar joint. lateral rotation: Isherwood method.
Tibia Talus _ _
Posterior subtalar articulation Calcaneus
Fig. 6- 1 08 AP oblique subtolar jOint: Isherwood method.
290
Ankle
'" AP PROJECTION Image receptor: 8 x 1 0 inch ( 1 8 x 24 cm) lengthwise or 24 X 30 cm crosswise for two i mages on one IR Position of patient Place the patient in the supine position with the affected limb fully extended.
•
Position of part Adjust the ankle joint in the anatomic position to obtain a true AP projection . Flex the ankle and foot enough to place the long axis of the foot in the vertical position (Fig. 6- 1 09). Ball and Egbert ' stated that the appear ance of the ankle mortise is not appre ciably altered by moderate plantar flex ion or dorsiflexion as long as the leg is rotated neither laterally nor medially. Shield gonads.
•
Structures shown The resulting i mage shows a true AP pro jection of the ankle joint, the distal ends of the tibia and fibula, and the proximal por tion of the talus. NOTE: The inferior tibiofibular articulation and the talofibular articulation will not be "open" nor shown in profile in the true AP projection. This is a positive sign for the radiologist be cause it indicates that the patient has no rup tured ligament or other type of separations. For this reason it is important that the po ition of the ankle be anatomically "true" for the AP projection demonstrated (Fig. 6- 1 1 0) .
EVALUATION CRITERIA
The following should be clearly demon strated: • Tibiotalar joint space • Ankle joint centered to exposure area • Normal overlapping of the tibiofibular articulation with the anterior tubercle sl ight ly superimposed over the fibula • Talus sl ightly overlapping the distal fibula • No overlapping of the medial talomal leolar articulation • Medial and lateral malleol i • Tal us with proper density • Soft tissue
•
•
Central ray Perpendicular through the ankle joint at a point midway between the malleol i . •
' Ball RP. Egben EW: Ruptured ligaments o f the an kle. AJR 50:770. 1 943.
Fig. 6- 1 09 AP ankle.
Fibula
Tibiotalar joint
Lateral malleolus
Tibia
Medial malleolus
Talus
Fig. 6- 1 1 0 AP ankle.
29 1
Ankle
.. LATERAL PROJECTION Mediolateral Image receptor: 8 x 1 0 inch ( 1 8 X 24 cm) Position of patient
o Have the supine patient turn toward the affected side until the ankle is lateral (Fig. 6- 1 1 1 ). Position of part o Place the long axi of the I R parallel with the long axi of the patient's leg and center it to the ankle joint. o Ensure that the lateral surface of the foot is in contact with the I R. o Dorsiflex the foot, and adju t it i n the lateral position. Dorsiflexion is re quired to prevent lateral rotation of the ankle. o Shield gonads.
Structures shown The re ulting i mage shows a true lateral projection of the lower third of the tibia and fibula, the ankle joint, and the tarsals (Fig. 6- 1 1 2) . EVALUATION CRITERIA
The fol lowing should be clearly demon strated: • Ankle joint centered to exposure area • Tibiotalar joint wel l visualized, with the medial and l ateral talar domes su perimpo ed • Fibula over the posterior half of the tibia • Distal tibia and fibula, talus, and adja cent tarsals • Den ity of the ankle sufficient to see the outline of distal portion of the fibula
Central ray o Perpendicular to the ankle joint, enter ing the medial malleolus
Fig. 6-1 1 1 Lateral ankle, mediolateral.
292
Ankle
Tibia
Fibula
Tibiotalar joint
A
Talus
B
Navicular Cuboid Calcaneus
c
Fig. 6-1 1 2 A, and B, Lateral ankle, mediolateral. C, Lateral ankle of an 8-year-old patient. Note the tibial epiphysis (arrow).
293
Ankle
LATERAL PROJECTION Lateromedial It is often recommended that the lateral projection of the ankle joint be made with the medial side of the ankle in contact with the I R. Exact positioning of the ankle i more ea ily and more consistently ob tained when the limb is rested on its com paratively flat medial surface. Image receptor: 8 x 1 0 inch ( 1 8 x 24 cm) Position of patient Have the supine patient turn away from the affected ide unti l the extended leg is placed lateral ly.
Central ray Perpendicular through the ankle joint, entering Y2 inch ( 1 .3 cm) superior to the lateral malleolus o
Structures shown The resulting i mage shows a lateral pro jection of the lower third of the tibia and fibula, the ankle joint, and the tarsals (Fig. 6- 1 1 4).
EVALUATION CRITERIA
The fol lowing should be clearly demon strated: • Ankle joint centered to expo ure area • Tibiotalar joint well vi ualized, with the medial and lateral talar domes uper i mposed • Fibula over the posterior half of the tibia • Distal tibia and fibula talu , and adja cent tar als • Density of the ankle sufficient to see the outline of distal portion of the fibula
o
Position of part Center the IR to the ankle joint, and ad ju t the IR so that it long axis is paral lel with the long axi of the leg. Adjust the foot in the lateral position. Have the patient turn anteriorly or pos teriorly as required to place the patella perpendicular to the horizontal plane (Fig. 6- 1 1 3 ). If necessary, place a support under the patient's knee. Shield gonads. o
o
o
o
o
Fig. 6- 1 1 3 Lateral ankle, lateromedial.
Fibula Tlblotalar joint Navicular Calcaneus
Fig. 6- 1 1 4 Lateral ankle, lateromedial.
294
Ankle
.. AP OBLIQUE PROJECTION Medial rotation Image receptor: 8 x 1 0 inch ( 1 8 X 24 COl) lengthwise or 24 X 30 COl crosswise for two images on one I R Position o f patient Place the patient in the supine position with the affected limb fully extended.
Structures shown The 45-degree medial oblique projection demonstrate the distal ends of the tibia and fibul a, parts of which are often super imposed over the talus. The tibiofibular articulation also hould be demonstrated (Fig. 6- 1 1 6).
o
Position of part Center the IR to the ankle joint midway between the mal leol i. and adjust the I R s o that its long axis is paral lel with the long axis of the leg. Dorsiflex the foot enough to place the ankle at nearly light-angle flexion (Fig. 6- 1 1 5 ). The ankle may be immobi lized with sandbags placed against the sole of the foot or by having the patient hold the ends of a strip of bandage looped around the ball of the foot. Rotate the patient's leg primari ly and the joot for all oblique projections of the ankle. Because the knee is a hi nge joint, rotation of the leg can come only from the hip joint. Positioning the ankle for the oblique projection requires that the leg and joot be medially rotated 45 degrees. Grasp the lower femur area with one hand and the foot with the other. Internally rotate the entire leg and foot together until the 45-degree position is achieved. The foot can be placed against a foam wedge for support. Shield gonads.
EVALUATION CRITERIA
The following should be clearly demon strated: • Distal tibia, fibula, and talus • Distal tibia and fibula overlap some of the talus • Talus and distal tibia and fibula ade quately penetrated • Tibiofibular articulation
o
o
o
o
Fig. 6- 1 1 5 AP oblique ankle, 45-degree medial rotation.
o
o
Central ray Perpendicular to the ankle joint, enter ing midway between the malleol i o
Fibula Tibiofibular joint
Tibia
Talus
Fig. 6- 1 1 6 AP oblique ankle, 45-degree medial rotation.
295
Ankle Mortise Jointl
.. AP OBLIQUE
Position of part Center the patient's ankle joint to the IR. • Grasp the distal femur area with one hand and the foot with the other. Assist the patient by internally rotating the en tire leg and foot together I S to 20 de grees until the intermalleolar plane is parallel with the IR (Fig. 6- 1 1 7).
•
•
Medial rotation Image receptor: 8 x 1 0 inch ( 1 8 X 24 cm) lengthwise or 24 X 30 cm crosswise for two image on one IR Position of patient Place the patient in the supine position.
•
The plantar urface of the foot should be placed at a right angle to the leg (Fig. 6- 1 1 8). Shield gonads.
Central ray Perpendjcular, entering the ankle joint midway between the malleoli
•
•
'Frank ED et al: Radiography of the ankle mortise, 62:354. 1 99 1 .
Radial Technol
Fig. 6- 1 1 7 AP oblique ankle, 15- to 2O-degree medial rotation for demonstration of the ankle mortise joint.
Fibula
Fig. 6- 1 1 8 Radiographer properly positioning the leg for demon stration of the ankle mortise joint. Note the action of the left hand (arrow) in turning the leg medially. Proper positioning re quires turning the leg but not the foot.
Tibia
Medial malleolus
A
Lateral malleolus
Ankle mortise joint Talus
Fig. 6- 1 1 9 AP oblique ankle, 1 5- to 20-degree medial rotation for demonstration of the ankle mortise joint. A, Properly positioned leg for demonstration of the mortise joint. B, Poorly positioned leg; radiograph had to be repeated. The foot was turned medially (white arrow) but not the leg. Note that the lateral mortise is closed (black arrow) be cause the l eg was not medially rotated. "
296
"
B
Ankle
Structures shown The entire ankJe mortise joint should be demonstrated in profi le. The three sides of the morti e joint should be vi ualized (Fig . 6- 1 1 9 and 6- 1 20).
EVALUATION CRITERIA
The fol lowing hould be clearly demon strated: • Entire ankle mortise joint • No overlap of the anterior tubercle of the tibia and the superolateral portion of the talus with the fibula
A
•
•
Talofibular joint space in profi le Talus demonstrated with proper den ity
c
B
Coronal plane 0° -J.rJl!!�flL. Intermalleolar .IU�""� plane Lateral malleolus •.
AP
AP oblique for mortise
AP oblique
Fig. 6- 1 20 Axial drawing of the inferior surface of the tibia and fibula at the ankle joint along with matching radiographs. A, AP ankle position with no rotation of the leg and foot. The drawing demonstrates the lateral malleolus positioned posteriorly when the leg is in true anatomic position. The radiograph shows normal overlap of the anterior tubercle and superolateral talus over the fibula (white arrows). B, AP oblique ankle, 1 5- to 2O-degree me dial rotation for demonstration of the ankle mortise. The drawing demonstrates both malle oli parallel with the IR. The radiograph clearly shows all three aspects of the mortise joint (ar
rows). C,
AP
oblique ankle, 45-degree medial rotation. The radiograph shows the tibiofibular
joint (arrow) and the entire distal fibula in profile. Note the larger upper arrows that show the wider space created between the tibia and fibula as the leg is turned medially for the two AP oblique projections. This space should be observed when the ankle radiographs are checked for proper positioning.
297
Ankle
AP OBLIQUE PROJECTION Lateral rotation Image receptor: 8 x 1 0 inch ( 1 8 x 24 cm) Position of patient Seat the patient on the radiographic table with the affected leg extended.
•
Position of part • Place the plantar urface of the patient's foot in the vertical position, and later ally rotate the leg and foot 45 degree . • Rest the foot against a foam wedge for support, and center the ankle joint to the lR (Fig. 6- 1 2 1 ). • Shield gonads. Central ray • Perpendicular, entering the ankle joint midway between the malleoli
Structures shown The lateral rotation oblique projection i useful i n determ i n i ng fractures and demonstrating the superior aspect of the calcaneus (Fig. 6- 1 22). EVALUATION CRITERIA
The fol lowing hould be clearly demon trated: • Subtalar joint • Calcaneal su lcus (superior portion of calcaneus)
Fig. 6- 1 21 AP oblique ankle, lateral rotation.
Fibula
Tibia
Medial malleolus Talus
Lateral malleolus
Fig. 6- 1 22 AP oblique ankle, lateral rotation.
298
Ankle
.. AP PROJECTION STRESS METHOD Stre tudies of the ankle joint usually are obtained after an inversion or eversion injury to verify the presence of a ligamen tous tear. Rupture of a ligament is demon strated by widening of the joint space on the side of the injury when, without mov ing or rotating the lower leg from the supine position, the foot is forcibly turned toward the opposite side. When the injury is recent and the ankle is acutely sensitive to movement, the or thopedic surgeon may inject a local anes thetic into the inus tar i preceding the ex ami nation. The physician adj usts the foot when it must be turned into extreme stress and holds or straps it in position for the exposure. The patient usually can hold the foot in the stress position when the injury is not too painful or after he or she has re ceived a local anesthestic by asymmetri cally pulling on a trip of bandage looped around the ball of the foot (Figs. 6- 1 23 to 6- 1 25 ).
Fig. 6- 1 23 A P ankle in neutral position. Use of lead glove and stress o f the joint i s required to obtain inversion and eversion radiographs (see Figs. 6- 1 25 and 6-1 26).
A
Fig. 6- 1 24 AP ankle. neutral position .
B
Fig. 6- 1 25 A, Eversion stress. No damage to the medial ligament is indicated. B, Inversion stress. Change iii jOint and rupture of lateral ligament (arrow) are seen.
299
An kles
AP PROJECTION WEIGHT-BEARING M ETHOD Standing This projection is performed to identify ankle joint space narrowing with weight bearing. Image receptor: 24 x 30 em eros wise Position of patient Place the patient in the upright position, preferably on a low platform that has a cassette groove. If such a platform is not available, use blocks to elevate the feet to the level of the x-ray tube ( Fig. 6- 1 26, A ) . Ensure that the patient has proper sup port. Never stand the patient on the ra diographic table.
•
•
Position of part Place the cassette in the cassette groove of the platform or between blocks. H ave the pat ient stand with heel s pushed back against the cassette and toes pointing straight ahead toward the x-ray tube. • Shield gonads. •
•
300
Ankles
Central ray Perpendicular to the center of the cassette TECHNICAL NOTE: If needed, use a mobile unit to allow the x-ray tube to reach the floor level.
Structures shown The resulting image shows an AP projec tion of both ankle joints and the relationship of the di tal tibia and fibula with weight bearing. It also demonstrates side to side compari on of the joint (Fig. 6- 1 26, 8). EVALUATION CRITERIA •
• •
•
Both ankles centered on the i mage Medial mortise is open Distal tibia and talu partially uperim pose the distal fibula Lateral mortise is closed
RESEARCH: Catherine E. Hearty, MS, RT( R ) performed the research and provided this new projection for this edition of the atlas.
B
A
Fig. 6- 1 26 A, AP weight-bearing ankles. B, AP weight-bearing ankles.
30 1
leg
'" AP PROJECTION For this projection, as well as the lateral and oblique projections described in the following sections, the long axis of the I R is placed parallel with the long axis of the leg and centered to the midshaft. Unless the leg is unusually long, the IR will ex tend beyond the knee and ankle joints enough to prevent their being projected off the IR by the divergency of the x-ray beam. The IR must extend from I to 1 1'2 (2.5 to 3.8 cm) inches beyond the joints. When the leg is too long for these al lowance and the site of the lesion is not known, two images should be made. Diagonal use of a 35 X 43 cm IR is also an option if the leg is too long to fit lengthwise and if such use is permitted by the faci I i ty. Image receptor: 1 8 x 43 cm or 35 X 43 cm for two images on one I R
Position of patient Place the patient in the supine position. •
Position of part Adjust the patient's body so that the pelvis is not rotated. Adjust the leg so that the femoral condyles are paral lel with the JR and the foot is vertical. Flex the ankle until the foot is in the vertical position. If necessary, place a sandbag against the plantar urface of the foot to i mmobilize it in the COITect po ition (Fig. 6- 1 27). Shield gonads.
•
•
•
•
•
Central ray • Perpendicular to the center of the leg
COMPUTED RADIOGRAPHY
Fig. 6- 1 27 AP tibia and fibula.
302
�
If one TR is used for two images, the un exposed side mu t be covered with lead. Scattered radiation reaching the IP phos phor will produce an undiagnostic image or computer artifacts on both sides.
Leg
Structures shown The resulting image shows the tibia, fibula, and adjacent joints (Fig. 6- 1 28).
EVALUATION CRITERIA
The following should be clearly demon strated: • Ankle and knee joints on one or more AP projections • Ankle and knee joints without rotation • Proxi mal and distal articulations of the tibia and fibula moderately overlapped • Trabecular detail and soft tissue for the entire leg
Fibula
Tibia
Medial malleolus
Lateral malleolus
A
B
c
Fig. 6- 1 28 A, AP tibia and fibulo. Long leg length prevented demonstration of the entire leg. A separate knee projection had to be performed on this patient. B, Short leg length allowed the entire leg to be shown. A spiral fracture of the distal tibia with accompanying spiral fracture of the proximal fibula (arrows) is seen. This radiograph demonstrates the importance of including the entire length of a long bone in trauma cases. C, AP tibia and fibula on a 4 year old with neurofibromatosis. (C,
Courtesy of Tamie Krohn.)
303
leg
'" LATERAL PROJECTION Mediolateral
•
Image receptor: 1 8 x 43 cm or 35 X 43 cm for two images on one IR Position of patient Place the patient in the supine position. •
Position of part Tum the patient toward the affected side with the leg on the J R . Adju t the rotation o f the body t o place the patella perpendicular to the I R, and ensure that a line drawn through the femoral condyle i al 0 perpendicular. Place sandbag supports where needed for the patient's comfort and to stabil ize the body position (Fig. 6- 1 29). •
•
Alternate method •
•
•
•
When the patient cannot be turned from the supine position, the lateral projec tion may be taken cro s-table u i ng a horizontal central ray. Lift the leg enough for an assi tant to slide a rigid support under the patient's leg. The IR may be placed between the legs and the central ray directed from the lateral side. Shield gonads.
Central ray Perpendicular to the mjdpoint of the leg •
COMPUTED RADIOGRAPHY
�
If one IR i u ed for two i mages, the un expo ed side must be covered with lead. Scattered radjation reaching the IP phos phor will produce an undiagno tic image or computer artifacts on both sides. Structures shown The re ulting image shows the tibia, fibula, and adjacent joints (Fig. 6- 1 30).
Fig. 6-1 29 Lateral tibia and fibula.
304
Leg
EVALUATION CRITERIA
The fol lowing should be clearly demon trated: • Ankle and knee joints on one or more images • Distal fibula lying over the posterior half of the tibia • Sl ight overlap of the tibia on the proxi mal fibular head • Ankle and knee joints not rotated • Possibly no superimposition of femoral condyles because of divergence of the beam • Moderate separation of the tibial and fibular bodies, or shafts except at their articular ends • Trabecular detail and soft tissue
Patella
Femoral condyles
Tibia
Fibula
Medial malleolus A
B
c
Fig. 6- 1 30 A, and B, Lateral tibia and fibula. C, Lateral postreduction tibia and fibula. showing a fixation device.
305
Leg
AP OBLIQUE PROJECTIONS Medial and lateral rotations
•
Image receptor: 1 8 x 43 cm or 35 X 43 cm for two exposures on one I R Position of patient Place the patient in the supine position on the radiographic table. •
Position of part Perform oblique projection of the leg by alternately rotating the limb 45 de grees medially (Fig. 6- 1 3 1 ) or laterally (Fig. 6- 1 32). For the medial rotation, ensure that the leg is turned inward and not just the foot. For the medial oblique projection, ele vate the affected hip enough to re t the medial side of the foot and ankle against a 45-degree foam wedge, and place a support u nder the greater trochanter. Shield gonads. •
•
Central ray Perpendicular to the midpoint of the I R •
Fig. 6- 1 3 1 A P oblique leg, medial rotation.
306
Fig. 6- 1 32 AP oblique leg, lateral rotation.
leg
COMPUTED RADIOGRAPHY
•
If one IR is used for two images, ensure that the unexposed ide is covered with lead. cattered radiation reaching the I P pho phor w i l l produce a n undiagno tic image or computer artifact , on both ides.
Structures shown The resulting image shows a 45-degree oblique projection of the bones and oft tissues of the leg and one or both of the adjacent joints (Fig . 6- 1 33 and 6- 1 34). EVALUATION CRITERIA
The fol lowing hould be clearly demon strated: Medial rotation • • •
Proxi mal and distal tibiofibular articu lations Maximum intero seous pace between the tibia and fibula Ankle and knee joint Lateral rotation
• •
Fi bula superimposed by lateral portion of tibia Ankle and knee joint
Fig. 6- 1 33 AP oblique leg. medial rotation. showing a fixation de vice.
Fig. 6- 1 34 AP oblique leg. lateral rotation. with a fixation device in place.
307
Knee
.. AP PROJECTION Radiograph of the knee may be taken with or without use of a grid. The size of the patient's knee and the preference of the radiographer and physician are the factors considered in reaching a decision. Attention is again called to the need for gonad shielding in examinations of the lower limb . ( Lead shielding i not shown on illu trations of the patient model be cause it would obstruct demonstration of the body position . ) Image receptor: 2 4 X 3 0 cm length wise Position of patient Place the patient in the supine po ition, and adjust the body so that the pelvis i not rotated.
Position of part With the IR under the patient's knee, flex the joint slightly, locate the apex of the patella, and as the patient extends the knee, center the IR about Y2 inch ( 1 .3 cm) below the patellar apex. This will center the IR to the joint space. • Adjust the patient's leg by placing the femoral epicondyle parallel with the I R for a true AP projection (Fig. 6- 1 35). The patella will l ie shghtly off center to the medial side. If the knee cannot be ful ly extended, a curved IR may be used. • ShieLd gonads. •
Central ray • Directed to a point Y2 i nch ( 1 .3 cm) in
•
•
ferior to the patellar apex. Variable, depending on the measurement between the anterior superior iliac spine (AS IS) and the tabletop (Fig. 6- 1 36), as follows! : 24
em
em
Structures shown The resulting i mage shows an AP projec tion of the knee structures (Fig. 6- 1 37). EVALUATION CRITERIA
The fol lowing should be clearly demon strated: • Open femorotibial joint space • Knee fully extended if patient' condi tion permjts • Interspaces of equal width on both sides if the knee i normal • Patella completely superimpo ed on the femur • No rotation of the femur and tibia • Slight superimposi tion of the fibular head if the tibia is normal • Soft tissue around the knee joint • Bony detail surrounding the patella on the distal femur
3 to 5 degrees caudad (thin pelvis) o degrees 3 to 5 degrees cephalad (large pelvis)
'Martensen KM: Alternate AP knee method assures open joint space, Radial Technol 64: 1 9, 1 992.
18 cm and below
1 9-24 cm
25 cm and above
9S! � ,
Fig. 6- 1 35 AP knee.
4
_
-,,_I�
Fig. 6 - 1 36 Pelvic thickness and central ray angles for AP knee ra diographs.
(Modified from Martensen KM: Alternate AP knee method assures open joint space. Radlol Techno/ 64: 1 9. 1 992.) 308
Knee
Femur Patella Lateral epicondyle
Lateral condyle
A
Lateral tibial plateau Intercondylar eminence
Head of fibula
Tibia
Fibula
c
B
Fig. 6- 1 37 A, AP knee with CR angled 5 degrees cephalad. Patient's ASIS to tabletop dis tance was greater than 25 cm. B, Same patient as A with CR perpendicular. Note joint space is not opened as well. C, AP knee on a 1 5 year old. Arrow pointing to a benign le sion in the tibia.
309
Knee
PA PROJECTION
Position of part Center a point 1,12 inch ( 1 .3 cm) below the patellar apex to the center of the [ R, and adjust the patient's leg so that the femoral epicondyles are parallel with the tabletop. Because the knee is bal anced on the medial side of the obliquely located patella, care must be used in adjusting the knee (Fig. 6- 1 38). Shield gonads.
•
Image receptor: 24 x 30 cm length wise Position of patient • Place the patient in the prone position with toes resting on the radiographic table, or place sandbags under the ankle for support.
•
Central ray • Directed at an angle of 5 degrees cau
dad to exit a point Y; inch ( 1 .3 cm) in ferior to the patel lar apex. Because the tibia and fibula are sl ightly inclined, the central ray will be parallel with the tib ial plateau.
-
---
-
-� ----
.� �----.
.
Fig. 6- 1 38 PA knee.
310
Knee
Structures shown The resulting i mage shows a PA projec tion of the knee (Fig. 6- 1 39). EVALUATION CRITERIA
The following should be clearly demon strated: • Open femorotibial joint space • Knee fully extended if the patient's condition perm its • I nterspace of equal width on both sides if the knee is normal • 0 rotation of femur if tibia is normal • Sl ight superimposition of the fibular head with the tibia • Soft tissue arou nd the knee joint • Bony detai l surrounding the patella
Femur
Tibial plateau
Tibia Fibula
Fig. 6- 1 39 PA knee.
31 1
Knee
.. LATERAL PROJECTION Mediolateral Image receptor: 24 X 30 cm lengthwise Position of patient • Ask the patient to turn onto the affected
side. En ure that the pelvis is not rotated. • For a standard lateral projection, have
the patient bring the knee forward and extend the other l i mb behind it ( Fig. 6- 1 40). The other l i mb may also be placed in front of the affected knee on a support block.
Position of part • A flexion of 20 to 30 degrees is usually
preferred because this position relaxes the muscles and shows the maximum volume of the joint cavity. I • To prevent fragment separation in new or unhealed patellar fracture , the knee should not be flexed more than 1 0 de grees. Place a support under the ankle. • Grasp the epicondyles and adj ust them so that they are perpendicular to the I R (condyles superimposed). The patella will be perpendicular to the plane of the IR (Fig. 6- 1 4 1 ). • Shield gonads. •
'Sheller S: Roentenographic studies on epiphyseal growth and os ification in the knee, Acta Radiol 1 95: 1 2, 1 960.
Fig. 6- 1 40 Lateral knee showing 5-degree cephalad angulation of central ray.
A
B
Fig. 6-141 A, Improperly positioned lateral knee. Note condyles not superimposed (black arrows) and patella is closed joint. B, Same patient as A after correct positioning. Condyles are superimposed and patellofemoral joint is open.
312
Knee
Central ray • Directed to the knee joint I inch (2.5 cm) distal to the medial epicondyle at an an gie of 5 to 7 degrees cephalad. This shght angulation of the central ray will prevent the joint space from being obscured by the magni fied i mage of the medial femoral condyle. In addition, in the lat eral recumbent position, the medial condyle will be slightly inferior to the lateral condyle. • Center the I R to the central ray. Structures shown The resulting radiograph shows a lateral i mage of the distal end of the femur, patel la, knee joint, proximal ends of the tibia and fibula, and adj acent soft tissue (Figs. 6- 1 42).
EVALUATION CRITERIA
The following should be clearly demon strated: • Femoral condyles superimposed (Locate the adductor tubercle on the posterior surface of the medial condyle to identify the medial condyle to determine whether the knee is overrotated or underrotated. ) • Open j o i n t space between femoral condyles and tibia • Patella in a lateral profile • Open pateliofemoraJ joint space • Fibular head and tibia sl ightly superim posed (Overrotation causes less super imposition, and underrotation causes more superimposition.) • Knee flexed 20 to 30 degrees • All soft tissue around the knee • Femoral condyles w ith proper density
Femur
Femoral condyles Patella A
B
Tibial plateau Tibia Fibula Fig. 6- 1 42 A. Lateral knee. B. Lateral knee showing severe arthritis.
313
Knees
.. AP PROJECTION WEIGHT-BEARING M ETHOD Standing Leach, Gregg, and Siber' recommended that a bilateral weight-bearing AP projec tion be routinely included in the radio graphic examination of althritic knees. They found that a weight-bearing study of len reveal narrowing of a joint space that appears nonnal on the non-weight-bearing study. Image receptor: 35 x 43 cm cross wise for bilateral image
Position of patient Place the patient in the upright position with back toward a vertical grid device. •
Position of part Adjust the patient's position to center the knees to the IR. Place the toes straight ahead, w ith the feet separated enough for good balance. Ask the patient to stand straight with knees fu lly extended and weight equal ly distributed on the feet • Center the lR 't; inch ( 1 .3 cm) below the apices of the patellae (Fig. 6- 1 43). Shield gonads.
Central ray Horizontal and perpendicular to the center of the IR, entering al a point \(2 inch ( 1 .3 cm) below the apice of the patellae
•
•
•
•
•
' Leach RE. Gregg T. and S i ber FJ: Weight-bearing radiography in osteoanhritis of the knee. Radiology 97:265. 1 970.
Structures shown The resulting i mage shows the joint spaces of the knees. Varu and valgu de formities can al 0 be evaluated with thi procedure (Fig. 6- 1 44). EVALUATION CRITERIA
The following hould be clearly demon strated: • No rotation of the knees • Both knees • Knee joint space centered to the expo sure area • Adequate IR size to demonstrate the longitudinal axis of the femoral and tib ial bodies or shafts
Fig. 6- 1 43 AP bilateral weight-bearing knees.
Femur
Patella Joint space Tibia Fibula Fig. 6- 1 44 AP bilateral weight-bearing knees.
314
Knees
PA PROJECTION ROSEN BE RG M ETHOD' WEIGHT-BEARING Standing flexion
Image receptor: 35 x 43 cm cross wise for bilateral knees Position of patient Place the patient in the standing position with the anterior aspect of the knees centered to the vertical grid device. •
Position of part For a direct PA projection, have the pa tient stand upright with knees in contact with the vertical grid device. Center the IR at a level Y2 inch ( 1 .3 cm) below the apices of the patellae. Have the patient grasp the edge of the grid device and flex knees to place the femurs at an angle of 45 degrees ( Fig. 6- 1 45 ) . Shield gonads.
•
•
•
•
Central ray Horizontal and perpendicular to the center of the J R . The CR is perpendicu lar to the tibia and fibula. A I O-degree caudal angle is sometimes used. •
Structures shown PA weight-bearing method i u eful for evaluating joint space narrow i ng and demonstrating articular cartilage disease ( Fig. 6- 1 46). The i mage is similar to those obtained when radiographing the i nter condylar fossa. EVALUATION CRITERIA
The fol lowing hould be clearly demon strated: • No rotation of the knees • Both knees • Knee joint centered to the exposure area NOTE: For a weight-bearing study of a single knee, the patient puts full weight on the af fected side. The patient may balance with slight pressure on the toes of the unaffected side. ' Rosenberg TD, et al: The forty-five degree pos teroanterior flexion weight-bearing radiograph of the knee. J BOlle Joilll SlIrg 70A: 1 479. 1 988.
Fig. 6- 1 45 PA projection with patient's knees flexed 45 degrees and using a perpendicular central ray.
Femur Joint space
Tibia Fibula Fig. 6- 1 46 PA projection with knees flexed 45 degrees and cen tral ray directed 1 0 degrees caudad.
315
Knee
.. AP OBLIQUE PROJECTION Lateral rotation
•
I mage receptor: 24 x 30 cm lengthwi e Position of patient Place the patient on the radiographic table in the supine position, and support the ankles. •
Position of part If necessary, elevate the hip of the unaf fected side enough to rotate the affected li mb. Support the elevated hip and knee of the unaffected ide (Fig. 6- 1 47). Center the I R Yz inch ( 1 .3 cm) below the apex of the patella. Externally rotate the limb 45 degrees. ShieLd gonads. •
Central ray Directed � inch ( 1 .3 cm) inferior to the patellar apex. The angle is variable, de pending on measurement between the ASIS and the tabletop, as follows: •
•
24
em
19 to 24
•
em
3 to 5
degrees caudad
3 to 5
degrees cephalad
o degrees
•
Structures shown The resulting image hows an AP oblique projection of the laterally rotated femoral condyle , patel la, tibial condyles, and head of the fibula (Fig. 6- 1 48). EVALUATION CRITERIA
Fig. 6- 1 47 AP oblique knee, lateral rotation.
The fol lowing hould be clearly demon strated: • Medial femoral and tibial condyles • Tibial plateaus • Open knee joint • Fibula superimposed over the lateral half of the tibia • Margin of the patella projected slightly beyond the edge of the lateral femoral condyle • Soft tissue around the knee joint • Bony detail on the di tal femur and proximal tibia
Femur
Patelia
Medial femoral condyle Lateral femoral condyle
Lateral tibial plateau
Medial tibial plateau
Medial tibial condyle
Fibula Tibia
Fig. 6- 1 48 AP oblique knee.
316
Knee
.. AP OBLIQUE PROJECTION Medial rotation
Position of part Medially rotate the l imb, and elevate the hip of the affected side enough to rotate the l imb 45 degrees. Place a support under the hip, if needed (Fig. 6- 1 49). • Shield gonads. •
Image receptor: 24 x 30 cm lengthwise Position of patient
•
Central ray • Directed I.ti inch ( 1 .3 cm) inferior to the patellar apex; the angle is variable, de pending on the measurement between the ASIS and the tabletop, as follows:
• Place the patient on the table in the
24
em
1 9 to 24
supine position, and support the ankJes.
em
3
to 5
degrees caudad
3
to 5
degrees cephalad
o degrees
Structures shown The resulting image shows an AP oblique projection of the medially rotated femoral condyles, patel la, tibial condyles, proxi mal tibiofibular joint, and head of the fibula (Fig. 6- 1 50). EVALUATION CRITERIA
_
...·_ d'
�
Fig. 6- 1 49 AP oblique knee, medial rotation.
The following should be clearly demon strated : • Tibia and fibula separated at their proximal articulation • Posterior tibia • Lateral condyles of the femur and tibia • Both tibial plateaus • Open knee joint • Margin of the patella projecting sl ightly beyond the medial side of the femoral condyle • Soft tissue around the knee joint • Bony detail on the distal femur and proximal tibia
Patella Medial femoral condyle
Lateral femoral condyle
Medial tibial plateau
Lateral tibial plateau
Medial tibial condyle Lateral tibial condyle
Tibiofibular articulation Fibula Tibia
Fig. 6· 1 50 AP oblique knee.
317
Knee
PA OBLIQUE PROJECTION Lateral rotation
Position of part Elevate the hip of the affected side, and laterally rotate the toes and knee to form a 45-degree angle. Support the hip (Fig. 6- 1 5 1 ). Shield gonads. Hol mblad l recommended that the knee be flexed about 1 0 degrees •
Image receptor: 24 x 30 cm length wise
•
Position of patient Place the patient on the radiographic table in the prone position. •
•
' Holmblad EC: Improved x-ray technic ill studying knee joints. SOl/lh Med J 32:240. 1 939.
Central ray Perpendicu lar through the knee joint at a level Y; inch ( 1 .3 cm) below the patel lar apex •
Structures shown The resulting i mage show a PA oblique projection of the laterally rotated femoral condyles, patel la, tibial condyle , and fibular head (Fig. 6- 1 52). EVALUATION CRITERIA
The fol lowing should be clearly demon strated: • Medial femoral and tibial condyles • Tibial plateaus • Open knee joint • Fibula superimposed over the lateral portion of the tibia • Patel lar margin projecting l ightly be yond the side of the lateral femoral condyle • Soft ti ue around the knee joint • Bony detail on the di tal femur and proximal tibia
Fig. 6- 1 5 1
PA oblique knee, lateral rotation.
Femur
Pateila
Lateral femoral condyle Medial femoral condyle
Medial tibial plateau
Medial tibial condyle Lateral tibial plateau Fibula Tibia Fig. 6- 1 52 PA oblique knee.
318
Knee
PA OBLIQUE PROJECTION Medial rotation Image receptor: 24 x 30 cm lengthwi e Position of patient Place the patient in the prone position.
•
EVALUATION CRITERIA
The fol lowing should be clearly demon strated: _ Tibia and fibula separated at their proxi mal articulation _ Posterior tibia _ Lateral condyles of the femur and tibia _ Both tibial plateaus
_ _
_
_
Open knee joint Margin of the patella projecting lightly beyond the side of the medial femoral condyle Soft tissue around the knee joint Bony detail on the distal femur and prox i mal ti bia
Position of part Medially rotate the leg and foot, and el evate the hip of the unaffected side to rotate the limb 45 degrees medially. Place a support under the hip, if needed (Fig. 6- 1 53). Shield gonads.
•
•
•
Central ray • Perpendicular through the knee joint at
the level Y2 inch ( 1 .3 cm) below the apex of the patella Structures shown The resulting image shows a PA oblique projection of the medially rotated femoral condyles, patella, tibial condyles, prox i mal tibiofibular joint, and fibular head (Fig. 6- 1 54). Fig. 6- 1 53 PA oblique knee. medial rotation.
Femur Patella
Lateral femoral condyle
Medial femoral condyle
Medial tibial plateau Lateral tibial condyle Proximal tibiofibular articulation
Tibia
Fibula Fig. 6- 1 54 PA oblique knee.
319
Intercondylar Fossa
.. PA AXIAL PROJECTION HOLMBLAD METHOD! The PA axial, or "tunnel," projection, fir t described by Hol mblad in 1 937, required that the patient a sume a kneeling position on the radiographic table. In 1 983 the Holmblad method was modified 0 that if the patient's condition al lowed, a standing position could be u ed.2 Image receptor: 8 x 1 0 i nch ( 1 8 X 24 cm) Position of patient After consideration of the patient's safety, place the patient in one of three positions: ( I ) tanding with the knee of interest flexed and re ting on a stool at the side of the radiographic table (Fig. 6- 1 55), (2) standing at the side of the ra diographic table with the affected knee flexed and placed in contact with the front of the fR (Fig. 6- 1 56), or (3) kneel ing on the radiographic table as origi nally described by HoLmblad, with the affected knee over the IR (Fig. 6- 1 57). In all three approaches, the patient leans on the radiographic table for support. •
Fig. 6- 1 55 PA axial intercondylar fossa. upright with knee on stool.
I Holmblad EC: Postero-anterior x-ray view of the knee in flexion. JAMA 1 09: 1 1 96, 1 937. 'Turner GW, Bums CB, Previtle RG: Erect positions for "tunnel" views of the knee, Radiol Tee/mol 55:640, 1 983.
Fig. 6- 1 56 PA axial intercondylar fossa. standing using horizontal central ray.
Fig. 6-1 57 PA axial intercondylar fossa, kneeling on radiographic table: original Holmblad method.
320
I ntercondylar Fossa
Position of part For all positions, place the IR against the anterior surface of the patient's knee, and center the [R to the apex of the patel la. Flex the knee 70 degrees from full exten ion ( 20-degree differ ence from the central ray, as shown in Fig. 6- 1 58). Shield gonads.
•
•
EVALUATION CRITERIA
The following should be clearly demon strated: • Open fossa • Posteroinferior surface of the femoral condyles • Intercondylar eminence and knee joint space
• • •
•
Apex of the patella not superimposing the fossa No rotation, evident by sl ight tibiofibu lar overlap Soft tissue in the fos a and interspaces Bony detail on the intercondylar emi nence, di tal femur, and proximal tibia
NOTE: The bilateral examination is described on p. 3 1 4 (also see Figs. 6- 1 45 and 6- 1 46).
Central ray Perpendicular to the lower leg, enter ing the midpoint of the I R for all three positions
•
Structures shown The resulting i mage shows the i nter condylar fossa of the femur and the me dial and lateral intercondylar tubercles of the intercondylar eminence in profile (Fig. 6- 1 59). Holmblad I stated that the degree of flexion used in this position widens the joint space between the femur and tibia and gives an improved i mage of the joint and the urface of the tibia and femur. ' Holmblad EC: Postero-anterior x-ray view of the knee in flexion, lAMA 109: 1 1 96, 1 937.
Fig. 6- 1 58 Alignment relationship for any of three intercondylar fossa approaches: Holmblad method.
Patella Lateral femoral condyle
Intercondylar fossa Medial femoral condyle
Medial intercondylar tubercle Lateral intercondylar tubercle
Fig. 6- 1 59 PA axial ("tunnel") intercondylar fossa: Holmblad method.
32 1
I ntercondylar Fossa
'" PA AXIAL PROJECTION CAMP-COVENTRY METHOD'
Image receptor: 8 x 1 0 inch ( 1 8 x 24 cm) lengthwise Position of patient Place the patient in the prone po ition, and adjust the body so that it i not ro tated.
•
Position of part Flex the patient' knee to either a 40- or 50-degree angle, and rest the foot on a suitable support. Center the upper half of the lR to the knee joint; the central ray angulation projects the joint to the center of the IR (Figs. 6- 1 60 and 6- 1 6 1 ). A protractor may be used beside the leg to determine the correct leg angle. Adj ust the leg so that the knee has no medial or lateral rotation . Shield gonads.
•
•
•
•
'Camp JD, Coventry MB: Use of special views in roentgenography of the knee joint, US Naval Med 81111 42:56, 1 944.
•
Central ray Perpendicular to the long axis of the leg and centered to the knee joint ( i .e., over the popliteal depression) Angled 40 degrees when the knee is flexed 40 degrees and 50 degree when the knee i flexed 50 degrees •
•
Structures shown This axial image demonstrates an unobtructed projection of the i ntercondyloid fossa and the medial and lateral inter condylar tubercles of the intercondylar emi nence (Figs. 6- 1 62 and 6- 1 63).
Fig. 6- 1 60 PA axiol ("tunnel") intercondylar fossa: Camp-Coventry
method. 322
EVALUATION CRITERIA
The fol lowing should be clearly demon strated: • Open fossa • Posteroinferior surface of the femoral condyles • I ntercondylar eminence and knee joint space • Apex of the patella not superimpo ing the fo sa • 0 rotation, evident by slight tibiofibu lar overlap • Soft tissue in the fo sa and i nterspace • Bony detail on the intercondylar eminence, distal femur, and proximal tibia NOTE: In routine examinations of the knee joint, an intercondylar fo a projection is usually in cluded to detect loose bodies (''joint mice"). The projection is also used in evaluating split and displaced canilage in oSleochondriti di se can and flattening, or underdevelopment, of the lateral femoral condyle in congenital slipped patella.
Fig. 6- 1 6 1 PA axial Ctunnel") Intercondylar fossa: Camp Coventry method.
I ntercondylar Fossa
A B
Pateila Intercondylar fossa
Lateral intercondylar tuberle Medial intercondylar tuberle
Fibula
Tibia Fig. 6- 1 62 Camp-Coventry method. A, Flexion of knee at 40 degrees (same patient as in Fig. 6-1 63). B, Flexion of knee at 40 degrees in a 1 3-year-old patient. Note epiphyses (ar rows).
Fig. 6- 1 63 Flexion of knee at 50 degrees (same patient as in Fig . 6-1 57): Camp-Coventry method.
323
I ntercondylar Fossa
AP AXIAL PROJECTION BECLl�RE M ETHOD
•
Image receptor: 8 x 1 0 inch ( 1 8 x 24 cm) crosswise Position of patient Place the patient in the supine position, and adjust the body so that it is not ro tated.
•
Position of part Flex the affected knee enough to place the long axis of the femur at an angle of 60 degrees to the long axis of the tibia. Support the k nee on sandbags (Fig. 6- 1 64 ) . Place the I R under the knee, and posi tion the IR so that the center point co incides with the •
•
Central ray Adjust the leg so that the femoral condyles are equidistant from the I R . I mmobilize the foot with sandbag . ShieLd gonads. •
•
Central ray Perpendicular to the long axis of the tibia, entering the knee joint Y; inch ( 1 .3 cm) below the patellar apex
•
Structures shown The resulting i mage shows the inter condylar fossa, intercondylar eminence, and knee joint (Figs. 6- 1 65 and 6- 1 66).
Femur
Lateral condyle Intercondylar fossa Medial condyle
Intercondylar eminence
Tibia
Fibula Fig. 6- 1 64 AP axial intercondylar fossa with transverse IR: Seclere method.
324
Fig. 6- 1 65 AP axial intercondylar fossa: Seclere method with identified anatomy.
I ntercondylar Fossa
EVALUATION CRITERIA
The fol lowing should be clearly demon strated: • Open intercondylar fossa • Posteroinferior surface of the femoral condyles • Intercondylar eminence and knee joint space • No superimposition of the fossa by the apex of the patella • No rotation, evident by sl ight tibiofibu lar overlap • Soft tissue in the fossa and interspaces • Bony detail on the intercondylar emi nence, distal femur, and proxi mal tibia
Fig. 6- 1 66 Same image as Fig. 6- 1 65. Note clear visualization of the intercondylar fossa.
325
Patella
.. PA PROJECTION Image receptor: 8 x 1 0 inch ( 1 8 X 24 cm) lengthwise Position of patient Place the patient in the prone po ition. • If the knee i painful, place one andbag under the thigh and another under the leg to relieve pressure on the patella.
•
Position of part Center the IR to the patel la. • Adj ust the position of the leg to place the patella parallel with the plane of the I R . This u ually requires that the heel be rotated 5 to 1 0 degrees laterally (Fig. 6- 1 67). • Shield gonads.
•
Fig. 6- 1 67 PA patella.
Central ray Perpendicular to the midpopliteal area exiting the patella. • Col limate closely to the patellar area. •
Structures shown The PA projection of the patella provides sharper recorded detail than in the AP pro jection because of a closer object-to [ mage receptor distance ( a I D ) (Fig . 6- 1 68 and 6- 1 69).
Base Patella Apex
EVALUATION CRITERIA
Fig. 6- 1 68 AP patella showing fracture (ar row).
The following hould be clearly demon strated: • Patella completely superimposed by the femur • Adequate penetration for vi ualization of the patella clearly through the super i mposing femur • No rotation
Fig. 6- 1 69 A, Conventional PA pro jection of the patella shows a verti cal radiolucent line (arrow) passing through the junction of the lateral and middle third of the patella. B, On tomography this defect ex tends from the superior to the inferior margin of the patella. It is a bipartite patella and not a fracture.
A 326
B
Patella
,. LATERAL PROJECTION Mediolateral Image receptor: 8 x 1 0 inch ( 1 8 x 24 cm) lengthwise Position of patient Place the patient in the lateral recum bent position.
•
Position of part Ask the patient to turn onto the affected hip. A sandbag may be placed under the ankle for support. Have the patient flex the unaffected knee and hip, and place the unaffected foot in front of the affected limb for stability. Flex the affected knee approx imately 5 to 1 0 degrees. I ncreasing the flexion re duces the patellofemoral joint space. Adju t the knee in the lateral position so that the femoral epicondyles are su perimposed and the patella i perpen dicular to the IR (Fig. 6- 1 70). Shield gonads. Center the IR to the patella. •
•
•
•
Central ray Perpendicular to the IR, entering the knee at the midpatellofemoral joint. Col li mate closely to the patellar area.
•
COMPUTED RADIOGRAPHY
�
Coll imation must be close to keep unnec essary radiation from reaching the I P phosphor. Structures shown The re ulting image show a lateral pro jection of the patella and patellofemoral joint space (Fig. 6- 1 7 1 ). EVALUATION CRITERIA
The following should be clearly demon strated: • Knee flexed 5 to 1 0 degrees • Open patellofemoral joint space • Patella in lateral profi le • Close col li mation
•
•
Fig. 6- 1 70 Lateral patella. mediolaterial.
Fig. 6- 1 7 1
Lateral patella. mediolaterial.
327
Patella
PA OBLIQUE PROJECTION Medial rotation Image receptor: 8 x 1 0 i nch ( 1 8 x 24 cm) lengthwi e Position of patient Place the patient in the prone position. •
Position of part Flex the patient's knee approximately 5 to 1 0 degrees. Medially rotate the knee 45 to 55 de grees from the prone position. Center the medial portion of the patella to the IR (Fig. 6- 1 72). Shield gonads.
Central ray Perpendicular to the I R, exiting the pal pated patella. Coll imate closely to the patellar area.
•
•
Structures shown A PA oblique i mage of the medial portion of the patella is demon trated free of the femur (Fig. 6- 1 73).
EVALUATION CRITERIA
The following should be clearly demon trated: • Majority of the medial patella free of superimposition of the femur • Lateral margin of patella superimpo ed over the femur • Closely coll imated i mage
•
•
•
•
Fig. 6- 1 72 PA oblique patella, medial rotation.
Fig. 6- 1 73 PA oblique patella.
328
Patella
PA OBLIQUE PROJECTION Lateral rotation Image receptor: 8 x 1 0 inch ( 1 8 x 24 cm) lengthwise Position of patient Place the patient in the prone position.
•
Position of part Flex the patient's knee 5 to 1 0 degrees, and external ly ( laterally) rotate the knee 45 to 55 degrees from the prone po ition. • Center the lateral portion of the patella to the J R (Fig. 6- 1 74). Shield gonads.
Central ray • Perpendicular to the IR, exiting the pal pated patella. • Colli mate closely to the patellar area. Structures shown The resulting i mage shows an oblique projection of the lateral aspect of the patella free of the femur (Fig. 6- 1 75).
EVALUATION CRITERIA
The fol lowing should be clearly demon strated: • Majority of the patella free of superim position of the femur • Medial margin of patella superimposed over the femur • Closely col li mated i mage
•
•
-
�----.
"
_
_
�
_ _
,.
r�1�
Fig. 6- 1 74 PA oblique patella, lateral rotation.
Fig. 6- 1 75 PA oblique patella, lateral ro tation.
329
Patella
PA AXIAL OBLIQUE PROJECTION KUCHENDORF M ETHOD lateral rotation
Image receptor: 8 x 1 0 inch ( 1 8 X 24 cm) lengthwise Position of patient Place the patient in the prone position. Elevate the hip of the affected side 2 or 3 inche . Place a sandbag under the ankle and foot, and adjust it so that the knee is slightly flexed (approximately 1 0 degrees) to re lax the mu c1es.
•
•
•
Fig. 6- 1 76 PA axial oblique patella. lateral rotation.
Position of part Center the [R to the patella. Laterally rotate the knee approxi mately 35 to 40 degrees from the prone posi tion (thi position i more comfortable for the patient than the direct prone, be cause no pressure is placed on the in jured patella. The patient rarely objects to the sl ight pressure required to dis place the patella lateral ly). Place the index finger again t the me dial border of the patella, and pres it laterally. Rest the knee on it anteromedial side to hold the patella in a po ition of lateral di placement (Figs. 6- 1 76 and 6- 1 77). Shield gonads. •
•
•
•
•
Central ray Directed to the joint pace between the patella and the femoral condyle at an angle of 25 to 30 degrees caudad. It en ters the posterior surface of the patella.
•
Fig. 6- 1 77 PA axial oblique patella, lateral rotation.
Structures shown The resulting i mage will how a l ightly oblique PA projection of the patella, with most of the patella free of uperimposed structures (Fig. 6- 1 78). EVALUATION CRITERIA
The following should be clearly demon strated: • M ajority of the patella free of uperim po ition by the femur • Patella and its outline where it i super impo ed by the femur
Patella Femoral condyle
Fig. 6- 1 78 PA axial oblique patella.
330
Patella and Patellofemoral Joint
TANGENTIAL PROJECTION HUGHSTON M ETHOD1 2 Radiography of the patella has been the topic of hundreds of articles. For a tan gential radiograph, the patient may be placed in any of the fol lowing body posi tion : prone, supine. lying on the side, seated on the table, seated on the radio graphic table with the leg hanging over the edge. or standing. Various author have described the de gree of flexion of the knee joint as being a little a 20 degree to as much as 1 20 degrees. Laurin] reported that patellar subluxation is easier to demonstrate when the knee is flexed 20 degrees and noted a limitation of u i ng this small angle. Modern radiographic equipment often will not permit uch small angles because of the large size of the col l imator. Fodor, M alott, and Wei nberg" and Merchant et aP recommended a 45-degree flexion of the knee, and Hughston6 recom mended an approximately 55-degree angle with the central ray angled 45 degrees.
•
•
•
Ensure that the col limator surface is not hot because this could burn the patient. Adju t the patient's leg so that it is not rotated medially or lateral ly from the vertical plane. Shield gonads.
Central ray Angled 45 degrees cephalad and di rected through the patellofemoral joint
•
EVALUATION CRITERIA
The following should be clearly demon strated: • Patella in profi le • Open patellofemoral articulation • Surfaces of the femoral condyles • Soft tissue of the femoropatellar articu lation • Bony recorded detail on the patella and femoral condyles
Structures shown The tangential image shows ubluxation of the patella and patellar fractures and al lows radiologic a sessment of the femoral condyle . Hughston recommended that both knees be examined for comparison ( Fig. 6- 1 80).
Image receptor: 8 x 1 0 inch ( 1 8 X 24 cm ) for unilateral exami nation ; 24 X 30 cm crosswise for bilateral examination Position of patient Place the patient in a prone position with the foot re ting on the radio graphic table. Adjust the body so that it is not rotated.
•
Position of part Place the IR under the patient' knee, and slowly flex the affected knee so that the tibia and fibu la foml a 50- to 60degree angle from the table. Rest the foot against the col li mator, or support it in posit ion (Fig. 6- 1 79).
•
Fig. 6- 1 79 Tangential patella and patellofemoral joint: Hughston method.
•
' H ughston JC:
ubluxation of the patella, J 80lle
Joillf Surg 50A: 1 003, 1 968.
'Kimberlin GE: Radiological assessment of the patellofemoral articulation and subluxation of the patella. Radial Techllol 45: 1 29. 1 973 . 'Laurin CA: The abnormal lateral patellofemoral an gie. J 80lle Jaillf Surg 60A :55, 1 968. 'Fodor J. Maloll Jc. Weinberg S: Accurate radiogra phy of the patellofemoral joint. Radial Tecllllol
Patella Femoral condyle
5 3 : 5 70. 1 9 2.
'Merchanl AC et al: Roentgenographic analysis of patellofemoral congruence. J 80lle Jail" Surg 56
: 1 39 1 . 1 974.
"Hugh ton JC: Subluxation of the patella. J BOlle JoiIlf Surg 50A: I OO3 . 1 968.
Patellofemoral articulation
Fig. 6- 1 80 Tangential patellofemoral joint: Hughston method. 331
Patella and Patellofemoral Joint
TANGENTIAL PROJECTION
Position of part
MERCHANT M ETHOD!
• Using the "axial v iewer" device, elevate
Image receptor: 24 x 30 cm cross wise for bilateral examination
•
the patient's knees approximately 2 inches to place the femora parallel with the tabletop (Figs. 6- 1 8 1 and 6- 1 82). Adjust the angle of knee flexion to 40 degree . ( Merchant reported that the degree of angulation may be varied be tween 30 to 90 degrees to demonstrate various patellofemoral disorders. ) Strap both legs together a t the calf level to control leg rotation and allow patient relaxation. • Place the IR perpendicular to the central ray and resti ng on the patient' hins (a thin foam pad aids comfort) approxi mately I foot distal to the patel lae.
•
SID: A 6-foot (2-m) S I D is recom mended to reduce magnification. Position of patient Place the patient supine with both knees at the end of the radiographic table. • Support the knees and lower legs by an adju table I R-holding device. 2 • To increase comfort and relaxation of the quadriceps femoris, place pil lows or a foam wedge under the patient's head and back. •
•
•
•
Ensure that the patient is able to relax. Relaxation of the quadriceps femoris is critical for an accurate diagnosi . I f these muscles are not relaxed, a sub luxed patella may be pulled back into the intercondylar sulcus, showing a false normal appearance. Record the angle of knee flexion for re producibi ljty during follow-up exami nation , because the severity of patella subl uxation commonly changes in versely with the angle of knee flexion. Shield gonads.
' Merchant AC et al: Roentgenographic analysis of patellofemoral congruence, J BOlle Joillt Surg 56A: 1 39 1 . 1 974. 'Merchant AC: "The Axial Viewer." Orthopedic Products. 2500 Hospital Dr., Bldg. 7, Mountain View, CA 94040.
Fig. 6- 1 8 1 Tangential patella and patellofemoral joint: Merchant method.
332
Fig. 6- 1 82 "The axial viewer" device.
Patella and Patellofemoral Joint
Central ray Perpendicular to the I R With 40-degree knee flexion, angle the central ray 30 degrees caudad from the horizontal plane (60 degrees from verti cal) to achjeve a 30-degree central ray to-femur angle. The central ray enters midway between the patellae at the level of the patellofemoral joint. •
Structures shown The bilateral tangential image demon strate an axial projection of the patellae and patel lofemoral joints (Fig. 6- 1 83). Because of the right-angle alignment of the I R and central ray, the patellae are seen as nondistorted albeit slightly magni fied i mages.
EVALUATION CRITERIA
The fol lowing should be clearly demon strated: • Patellae in profi le • Femoral condyle and intercondy lar sulcus • Open patellofemoral articulations
Patella
Patellofemoral joint Lateral condyle
A
B
Fig. 6- 1 83 A. Normal tangential radiograph of congruent patellofemoral joints, showing the patellae to be well centered with a normal trabecular pattern. B. Abnormal tangen tial radiograph showing abnormally shallow intercondylar sulci, misshapen and laterally subluxed patellae, and incongruent patellofemoral joints (left worse than right).
(Courtesy Alan J. Merchant.)
333
Patella and Patellofemoral Joint
.. TANGENTIAL PROJECTION
If the patient is eated on the radio graphic table, hold the IR securely in place (Fig. 6- 1 86). Alternative positions are shown in Figs. 6- 1 87 and 6- 1 88.
SETIEGAST M ETHOD
A
1 5 - 20°
Because of the danger of fragment dis placement by the acute knee flexion re quired for this procedure, this projection hould not be attempted until a trans verse fracture of the patella has been ruled out with a lateral image, or if the patient is in pain. Image receptor: 8 x 10 inch ( 1 8 X 24 Col) Position of patient Place the patient in the supine or prone position. The latter is preferable be cause the knee can usual ly be flexed to a greater degree and immobil ization is easier (Figs. 6- 1 84 and 6- 1 85).
•
Fig. 6- 1 84 Tangential patella and patellofemoral joint: Settegast method.
-
.
334
Position of part Flex the patient' knee lowly as much as possible or until the patella is per pendicular to the IR if the patient' con dition permits. With slow, even flexion, the patient will be able to tolerate the position, whereas quick, uneven flexion may cause too much pain. If de ired, loop a long strip of bandage around the patient's ankle or foot. Have the patient gra p the ends over the shoulder to hold the leg in po ition. Gently adj ust the leg 0 that its long axis i vertical.
•
---�
---
.
Fig. 6- 1 85 Tangential patella and patellofemoral Joint: Settegast method.
Fig. 6- 1 86 Tangential patella and patellofemoral joint: Settegast method.
Fig. 6- 1 87 Tangential patella and patellofemoral Joint: patient seated.
Fig. 6- 1 88 Tangential patella and patellofemoral joint: patient lateral.
Patella and Patellofemoral Joint
•
•
•
Place the IR transversely under the knee, and center it to the joint space between the patella and the femoral condyles. Shield gonads. By maintaining the same O I D and S I D relationships, this position can be obtai ned with the patient in a lateral or seated posi tion ( see Figs. 6- 1 87 and 6- 1 88).
NOTE: When the central ray is directed toward the patient's upper body ( see Figs. 6- 1 86 and 6- 1 87), the thorax and thyroid should be shielded. Gonad shielding (not shown) should be lIsed in all patients.
Central ray Perpendicular to the joint space be tween the patella and the femoral condyles when the joint is perpendicu lar. When the joint is not, the degree of central ray angulation depends on the degree of flexion of the knee. The angu lation typically will be 1 5 to 20 degrees. Close col l imation is recommended. •
•
COMPUTED RADIOGRAPHY
�
Col limation must be close to prevent un necessary radiation from reaching the IP phosphor.
A
Structures shown The resu lting image hows vertical frac tures of bone and the articulating surfaces of the patel lofemoral articulation (Figs. 6- 1 89 and 6- 1 90). EVALUATION CRITERIA
The following should be clearly demon strated: • Patella in profile • Open patel lofemoral articulation • Surfaces of the femoral condyle • Soft tissue of the patellofemoral ruticu lation • Bony detail on the patella and femoral condyles B
Patella
Patellofemoral articulation Lateral femoral condyle
Medial femoral condyle
Fibula
Fig. 6- 1 89 A, Tangential patella and patellofemoral joint: Settegast method. a, Fracture (arrow).
Fig. 6- 1 90 Bilateral patella examination. For this examination, the legs should be strapped
together at the level of the calf, using an appropriate binding to control femoral rotation. 335
Femur
.. AP PROJECTION If the femoral heads are separated by an unusually broad pelvis, the bodie ( hafts) will be more strongly angled toward the midline. Image receptor: 1 8 X 43 cm or 35 X 43 cm Position of patient Place the patient in the supine position. Check the pelvis to ensure it is not ro tated.
•
•
Position of part • Center the affected thigh to the midline of the I R . When the patient is too tall to include the entire femur, i nclude the joint clo est to the area of interest on one i mage (Fig. 6- 1 9 1 ). With the knee included
For projection of the distaL femur, ro tate the patient's l i mb i nternally to place it in true anatomic position. The l imb will naturally be turned externally when laying on the table. Ensure that the epicondyle are parallel with the IR. • Place the bottom of the I R 2 inches (5 cm) below the knee joint.
•
With the hip included • For projection of the proximaL femur,
which must include the hip joint, place the top of the IR at the level of the ASIS. Rotate the limb internally 10 to 15 de grees to place the femoral neck in pro file. • Shield gonads.
•
Central ray Perpendicular to the midfemur and the center of the I R
•
Structures shown The resulting i mage shows an AP projec tion of the femur, including the knee joint and/or hip ( Fig . 6- 1 92 and 6- 1 93).
Femur
Lateral condyle Tibia Fig. 6- 1 9 1 AP distal femur.
336
Fig. 6 - 1 92 A P right distal femur.
Femur
EVALUATION CRITERIA
The following should be clearly demon strated: • Majority of the femur and the joint nearest to the pathologic condition or site of injury (A second projection of the other joint is recommended . ) • Femoral neck not foreshortened o n the proximal femur
•
•
• •
•
Lesser trochanter not seen beyond the medial border of the femur or only a very small portion seen on the proxi mal femur No knee rotation on the distal femur Gonad shielding when indicated, but the shield not covering proxi mal femur Any orthopedic appliance in its entirety Trabecular recorded detail on the femoral shaft
Acetabulum
Femoral head
Greater trochanter
Femoral neck
Lesser trochanter
B
A
Femoral body (shaft)
Fig. 6- 1 93 A, AP proximal femur. B, AP proximal femur showing a "total hip" arthroplasty procedure. 337
Femur
.. LATERAL PROJECTION
Position of part
Mediolateral •
Image receptor: 1 8 X 43 cm or 35 X 43 cm lengthwise Position of patient Ask the patient to turn onto the affected side. Adjust the body position, and center the affected thigh to the midline of the grid. •
•
•
•
Fig. 6- 1 94 Lateral distal femur
338
With the hip included
With the knee included
•
For projection of the distal femur, draw the patient's uppermost limb forward and supp0l1 it at hip level on sandbags. Adj ust the pelvis in a true lateral posi tion (Fig. 6- 1 94). Flex the affected knee about 45 degrees, place a sandbag under the ankle, and ad just the body rotation to place the epi condyles perpendicular to the tabletop. Adjust the position of the Bucky tray so that the l R project approxi mately 2 inches (5 cm) beyond the knee to be incl uded.
•
•
•
For projection of the proximal femur, place the top of the IR at the level of the ASIS. Draw the upper limb posteriorly, and support it. Adju t the pelvi 0 that it is rolled pos teriorly just enough to prevent superim position; 1 0 to 1 5 degrees from the lat eral position is sufficient (Fig. 6- 1 95). Shield gonads.
Fig. 6- 1 95 Lateral proximal femur.
Femur
Central ray Perpendicular to the midfemur and the center of the I R •
Structures shown The resulting i mage shows a lateral projec tion of about three fourths of the femur and the adjacent joint. If needed, use two I Rs for demonstration of the entire length of the adult femur (Fig . 6- 1 96 and 6- 1 97).
EVALUATION CRITERIA The following should be clearly demon strated: • Majority of the femur and the joint near est to the pathologic condition or site of injury (A second radjograph of the other end of the femur is recommended. ) • Any orthopedic appliance in its entirety • Trabecular detail on the femoral body With the knee included
• • •
•
NOTE: Because of the danger of fragment dis placement, the aforementioned position is not recommended for patients with fracture or pa tients who may have destructive disease. Patients with these conditions should be exam ined in the supine position by placing the I R vertically along the medial or lateral aspect of the thigh and knee and then directing the cen tral ray horizontally. A wafer grid or a grid front IR should be used to mini mize secondary radiation.
Superimposed anterior sUiface of the femoral condyles Patella in profile Open patellofemoral space Inferior surface of the femoral condyles not superimposed because of divergent rays With the hip included
•
•
Opposite thigh not over area of interest Greater and lesser trochanters not prominent
Femoral head
Greater trochanter Femoral neck Lesser trochanter Ischial tuberosity
Femoral body
Fig. 6- 1 96 Lateral distal femur.
Fig. 6 - 1 97 Lateral proximal femur.
339
Lower Limbs
Hips, Knees, and Ankles
AP PROJECTION WEIGHT-BEARING METHOD1.2 Standing NOTE: A specially buil t, long grid holder con sisting of three grids, each 1 7 inches (43 cm) long, is required to hold the 5 1 -inch ( 1 30 cm) I R and it trifold fi lm.
Image receptor: 14 X (3 1 X 1 30 cm) lengthwise
Position of part Have the patient tand on a 2-inch (5 cm) riser so that the ankle joint is visible on the i mage. The bottom of the grid unit is positioned behind and be low the riser. Measure both lateral malleoli , and po sition the legs so that they are exactly 20 em apart. If this distance cannot be achieved, measure the width of the mal leol i and indicate this number on the request form. This image must be performed the same way for each re turn visit by the patient. En ure that the patient's toes are po i tioned straight forward in the anatomic po ition (Fig. 6- 1 98). Ensure that the patient is distributing weight equally on both feet. Mark with a right or left side marker, and place a magnification marker in the area of the knee. Place a wedge fi lter (commercially available for this projection) in the ap propriate position on the coll i mater (Fig. 6- 1 99). This filter i necessary to compensate for the difference in thick nes between the hip joint and ankle joint. Shield gonads. Respiration: Suspend.
•
51
inch
SID: 8 feet (244 cm). Thi rrunt mum length S l D is required to open the col li mators wide enough to expose the en tire 5 1 -i nch length of the IR.
•
•
•
Position of patient Stand the patient with the back against the upright grid unit. •
'Krushell R et al: A comparison of the mechanical and anatomical axes in arthritic knees. In Proceedings oj rhe Kllee Sociery. 1 985- 1 986. Aspen, 1 987 'Peterson TD. Rohr W: I mproved assessment of lower extremity alignment using new roentgeno graphic techniques. Clill Orrhop Rei Res 2 1 9, June 1 987
•
•
NOTE: A graduated speed screen (3 ection I 3 peeds) may be used in place of a wedge filter.
Central ray Perpendicular to the I R, entering mid way between the knee at the level of the knee joint. Coll i mate appropriately, and ensure that the hip joint and ankle joints will be seen on the image. •
•
Structures shown This projection demon trates the entire right and left l imbs from the hip joint to the ankle joint (Fig. 6-200) . EVALUATION CRITERIA
The following should be clearly demon strated: • Appropriate den ity to visual ize the hips to the ankle • Both feet in anatomic po ition • Hips, knees, and ankles • Right or Left marker and a magnifica tion marker near the knee
•
•
Fig. 6- 1 98 Patient in position for radiograph of lower limbs: hips, knees. and ankles. The patient is placed in the anatomic posi tion. Note that the patient is standing on a raised platform so that the ankles are shown. 340
Fig. 6- 1 99 Special filter for lower limb projections. The filter en ables the hips, knees, and ankles to be demonstrated on one ra diograph.
Lower Limbs
B A
Fig. 6-200 At and Bt Lower limbs: hips, knees, and ankles. Arrows point to magnification marker taped to knee.
341
OUTLINE
SUMMARY OF PROJECTIONS
PROJECTIONS,
POSITIONS
& M ETHODS
R or L CHASSARD-LAPINE MODIFIED CLEAVES
362 Axlolateral
Hlp
AP
Hlp
Lateral (medlolateral)
LAUENSTEI N; HICKEY
Hlp
Axiolateral
DANELlU5-MILLER
Hip
Axiolateral
CLEMENTS-NAKAYAMA
374
Hlp
Axlolateral
FRIEDMAN
376
Hip
PA oblique
RAO or LAO
HSIEH
378
Hlp
Mediolateral oblique
RAO or LAO
LlLIENFELD
366 368 370 372
I I
I
l
ORIGINAL CLEAVES
Femoral necks
364
• • •
380
Acetabulum
PA axial oblique
RAO or LAO
TEUFEL
382
Acetabulum
AP oblique
RPO or LPO
JUDET
384
Anterior pelvic bones
PA
385
Anterior pelvic bones
AP axial
TAYLOR
386
Anterior pelvic bones
Superoinferlor axial
LlLIENFELD
387
Anterior pelvic bones
PA axial
388
ilium
AP and PA oblique
STAUNIG RPO and LPO, RAO and LAO
Icons in the Essential column indicate projections frequently performed In the United States and Canada. Students should be competent in these projections.
"'1
ANATOMY
The pelvis serves as a base for the trunk and a girdle for the attachment of the lower l imbs. The pelvis consi ts of four bone : two hip bones. the sacrum. and the coccyx. The pelvic girdle is compo ed of only the two hip bones, however.
Hip Bone
ILIUM
The hip bone is often referred to a the os coxae, and some textbooks continue to re fer to it as the innominate bone. The most widely used term is hip bone. The hip bone con i t of the ilium. pu bis. and ischium (Fig . 7- 1 and 7-2). These three bones join together to form the acetabulum. the cup-shaped socket that receives the head of the femur. The il ium, pubis, and ischium are eparated by cartilage in youth but become fused into one bone in adulthood.
The ilium consists of a body and a broad, curved portion called the ala. The body of the ilium form approximately two fifths of the acetabulum superiorly (Fig. 7-3). The ala project superiorly from the body to form the prominence of the hip. The ala has three borders: anterior, posterior, and superior. The anterior and po terior bor ders present four prominent projections: Anterior uperior iliac spine Anterior inferior iliac spine Po terior superior iliac spine Po terior inferior iliac pine The anterior superior iliac spine (ASIS) is an important and frequently used radio graphic positioning reference point. The superior margin extending from the ASIS to the posterior superior il iac spine is called the iliac crest. The medial urface of the wing contain the iliac fossa and is separated from the body of the bone by a smooth, arc-shaped ridge, the arcuate line, which form a part of the circumfer ence of the pelvic bri m. The arcuate l ine passes obliquely, inferiorly, and medially to i ts j unction with the pubis. The inferior and posterior portion of the wing present a large, rough urface, the auricular sur face, for articulation with the sacrum. This articular urface and the articular surface of the adjacent acrum have irregular ele vations and depressions that cause a par tial interlock of the two bone . Below thi surface the ilium curves inward, forming the greater sciatic notch. •
•
•
Iliac crest
Ilium Auricular surface
Anterior superior iliac spine Anterior
,..-...--- Posterior inferior iliac spine
Pubis
Ischium Obturator foramen
Ischial ramus
Inferior ramus
Fig. 7 - 1 Anterior aspect of right hip bone.
Iliac crest
ilium
Anterior superior iliac spine Posterior inferior iliac spine
--iL.-....
-
Obturator foramen
Ischial spine Lesser sciatic notch
Ischial tuberosity
Pubis
Ischial ramus
Fig. 7-2 Lateral aspect of right hip bone.
Fig. 7 -3 Lateral aspect of right hip bone showing its three parts. 345
PUBIS
ISCHIUM
The pubis consists of a body, the superior ramus, and the inferior ramus. The body of the pubis forms approxi mately one fifth of the acetabulum anteriorly (see Fig. 7-3 ). The superior ramus projects i nferi orly and medially from the acetabulum to the midl ine of the body. There the bone curves inferiorly and then posteriorly and laterally to join the ischium. The lower prong is termed the inferior ramus.
The ischium consist of a body and the is chial ramus. The body of the ischium forms approximately two fifths of the ac etabulum posteriorly (see Fig. 7-3). It pro jects posteriorly and inferiorly from the acetabulum to form an expanded portion called the ischial tuberosity. When the body is in a eated-upright position, its weight rests on the two ischial tuberosities. The ischial ramus projects anteriorly and medially from the tubero ity to it junction with the inferior ramus of the pubis. By this posterior union the rami of the pubis and ischium enclose the obturator fora men. At the superoposterior border of the body is a prominent projection cal led the ischial spine. Ju t below the ischial spine is an indentation, the lesser sciatic notch.
Greater trochanter
Fovea _J.,....c... , capitis Articular surface
A
Anterior
Fovea capitis
Head
Head
Greater
.-�- trochanter
Intertrochanteric crest B
Posterior
Body
Greater trochanter
c
Lesser trochanter Body ----tIflFig. 7-4 Proximal right femur. A, Anterior aspect. B, Medial aspect. Note that the body is positioned 1 5 to 20 degrees posterior from the head. C, Posterior aspect. D, Posterior as pect of right proximal human femur. Note anatomical details, compare to C.
346
o
Proximal Femur The femur is the longest, strongest, and heavie t bone in the body. The proximal end of the femur consists of a head, a neck, and two large proce ses: the greater and lesser trochanters (Fig. 7-4). The smooth, rounded head is connected to the femoral body by a pyramid-shaped neck and is received into the acetabu lar cavity of the hip bone. A small depression at the center of the head, the fovea capitis, at taches to the l igamentum capitis femoris ( Fig. 7-5 ). The neck is constricted near the head but expands to a broad base at the body of the bone. The neck projects medially, superiorly, and anteriorly from the body. The trochanters are situated at the j unction of the body and the base of the neck. The greater trochanter is at the superolateral part of the femoral body, and the lesser trochanter is at the posteromedial part. The promi nent ridge extending between the trochanters at the base of the neck on the posterior surface of the body is cal led the intertrochanteric crest. The Ie s promi nent ridge connect ing the trochanters anteriorly is cal led the intertrochanteric lille. The femoral neck and the intertrochanteric crest are two common site of fractures in the el derly. The superior portion of the greater trochanter projects above the neck and curves slightly posteriorly and medial ly.
Fig. 7-5 Hip joint. Coronal section of proximal femur In acetabulum.
347
The angulation of the neck of the femur varies considerably with age, sex, and tature, I n the average adult the neck pro jects anteriorly from the body at an angle of approxi mately 1 5 to 20 degrees and su periorly at an angle of approximately 1 20 to 1 30 degrees to the long axis of the femoral body (Fig, 7-6). The longitudinal plane of the femur is angled about 1 0 de grees from vertical. I n youth the latter an gle is wider; that is, the neck is more ver tical in position. I n wide pelvise the angle is narrower, placing the neck in a more horizontal position.
;' ::::
I
"
,
I , I
\,
.. .
' ' '
i
,
\" " ,
. .. . . ..
..
'"
. .
,..
:
, ,
'
.'!.: - -
.'
I
:,�::'" ,/ .
,'
,
', ... ...
�' r
.... - - � ; - ..
:
� \ \'. '.
.. ..
A
. ...
..
" .
......
.. >�; ...
...
..
,
'"
.
20°
,
I
;,
!
'. -. .. .. ... _...
"
\ ... ... .. .. -
_ _
: !
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:
)
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B Fig, 7-6 A, Anterior aspect of right femur, B, Lateral aspect of right femur, C, Superoinferior view of posterior aspect of a human femur showing the 15 to 20 degree anterior angle of the femoral neck,
348
c
Articulations of the Pelvis A summary of the three joints of the pelvis and upper femora i contained in Table 7- 1 and Fig. 7-7, and a de cription follows. The articulation between the ac etabulum and the head of the femur (the hip joint) is a synovial ball-and-socket joint that permits free movement in all di rections. The knee and ankle joints are h inge joints; thus the wide range of mo tion of the lower limb depends on the bal l and-socket joint of the hip. Because the knee and ankle joints are hinge joint , me dial and lateral rotations of the foot cause rotation of the entire li mb, which i cen tered at the hip joint.
TABLE 7 - 1 Joints of the pelvis and upper femora
Structural classification Joint
Hip joint Pubic symphysis Sacroiliac
Tissue
Synovial Cartilaginous Synovial
Type
Ball and socket Symphysis Irregular gliding"
Movement
Freely movable Slightly movable Slightly movable
·Some anatomists term this a synovial fibrous joint.
Pubic symphysis joint
Fig. 7-7 Joints of the pelvis and upper femora.
349
TABLE 7-2 Female and male pelvis characteristics
Feature
Female
Male
Shape Bony structure Superior aperture (inlet) Inferior aperture (outlet)
Wide, shallow Light Oval Wide
Narrow, deep Heavy Round Narrow
The pubes of the hip bones articulate with each other at the anterior midline of the body, forming a joint called the pubic symphysis. The pubic symphysis is a car tilaginous symphysis joint. The right and left ilia articulate with the acrum po teriorly at the sacroiliac joints. The acroil iac articulation are synovial irregular gliding joints. Because the bones of the sacroil iac joint interlock, movement i very limited or nonexi tent.
Pelvis The female pelvis (Fig. 7-8) is l ighter in tructure than the male pelvis (Fig. 7-9) . It is wider and shal lower, and the inlet is larger and more oval shaped. The acrum is wider, it curves more sharply posteri orly, and the acral promontory is flatter. The width and depth of the pelvis vary with stature and gender (Table 7-2). The female pelvis is shaped for childbearing and delivery. The pel vi is divided into two portion by an oblique plane that extends from the up per anterior margin of the acrum to the up per margin of the pubic symphy is. The boundary line of thi plane is called the brim of the pelvis (see Figs. 7-8 and 7-9). The region above the brim i called thefalse or greater pelvis, and the region below the brim is called the true or lesser pelvis. The brim forms the superior aperture, or inlet, of the true pelvis. The inferior aperture, or outlet, of the true pelvis i measured from the tip of the coccyx to the inferior margin of the pubic symphy i in the anteropo terior direction and between the ischial tuberosities in the horizontal direction. The region between the inlet and the outlet is called the pelvic cavity (Fig. 7- 1 0). When the body is in the upright or eated position, the brim of the pelvi form an angle of approxi mately 60 de grees to the horizontal plane. Thi angle varie with other body positions; the de gree and direction of the variation depend on the l umbar and sacral curves.
Fig. 7 8 Female pelvis. -
Pubic symphysis
F ig . 7-9 Male pelvis.
Socral promontory Folse pelvis !
� §P .§
Pubic symphysis
8
�
True pelvis
----m- Pelvic cavity
Coccyx
Fig. 7 1 0 Midsagittal section showing inlet and outlet of true pelvis. -
350
Localizing Anatomic Structures The bony landmarks u ed in radiography of the pel is and hip are as follow : I l iac crest ASIS Pubic symphy i Greater trochanter of the femur Ischial tuberosity Tip of the coccyx Mo t of the e points are ea ily palpable, even in hypersthenic patients (Fig. 7- 1 I ). However, because of the heavy muscle i mmediately above the iliac crest, care must be exercised in locating this structure to avoid centering errors. It is advi able to have the patient inhale deeply; while the muscles are relaxed during expiration, the radiographer hould palpate for the highe t point of the iliac cre t. The highest point of the greater tro chanter, which can be palpated immedi ately below the depression in the soft tisues of the lateral surface of the hjp, is in the arne horizontal plane a the mjdpoint of the hjp joint and the coccyx. The mo t prominent point of the greater trochanter is in the arne horizontal plane a the pu bic ymphysi (see Fig. 7- 1 I ). The greater trochanter is most promi nent laterally and more easily palpated when the lower leg is medially rotated. When properly used, medial rotation fa cilitates localization of hip and pelvi cen tering points and avoids distortion of the •
•
•
•
•
•
proximal end of the femur during radiog raphy. I mproper rotation of the lower leg can rotate the pelvis. Consequently, the positioning of the lower leg is important in radiography of the hip and pelvis; the feet must be i mmobilized in the correct position to avoid distortjon of the i mage. Traumatic injuries or pathologic condi tions of the pelvis or lower limb may rule out the possibility of medial rotation. The pubic symphysis can be palpated on the mjdsagittal plane and on the same hori zontal plane as the greater trochanters. By placing the fingertips at this location and performing a brief downward palpation with the hand fiat, palm down, and fingers together, the radiographer can locate the su perior margin of the pubic symphysis. To avoid possible embarra sment or rrusunder standing, the radiographer should advise the patient in advance that thjs and other palpations of pelvic landmark are part of normal procedure and nece sary for an ac curate exarrunation. When carried out in an efficient and professional manner with repect for the patient's condition, uch pal pations are generally well tolerated.
Anterior superior iliac spine ------->.-..1 Head 1 .5 in. - - - - - Neck 2.5 in. - - -
Iliac crest
The hip joint can be located by palpat ing the ASIS and the superior margin of the pubic symphysis (Fig. 7- 1 2). The mid point of a line drawn between the e two points is directly above the center of the dome of the acetabu lar cavity. A li ne drawn at right angles to the midpoint of the first line lies parallel to the long axis of the femoral neck of an average adult in the anatomic position. The femoral head lies I � i nches (3.8 cm) distal and the femoral neck is 2 � (6.4 cm) distal to this point. For accurate localization of the femoral neck in atypical patient or in those in whom the limb is not in the anatomic po sition, a line is drawn between the ASIS and the uperior margin of the pubic sym physis, and a second line is drawn from a point I inch ( 2.5 cm) inferior to the greater trochanter to the mjdpoint of the previ ously marked li ne. The femoral head and neck lies along this line ( ee Fig. 7- 1 2).
1 inch
Superior margin of symphysis pubis
A
Anterior superior Iliac spine ---'.,.._-+1
Greater trochanter
Fig. 7 - 1 1 Bony landmarks and localization planes of pelvis.
B
Fig. 7- 1 2 A, Method of localizing the right hip joint and long axis of femoral neck. B, Suggested method of localizing the right hip. Left thumb is on ASIS. a nd second finger is on superior margin of pubic symphysis. Note central ray is positioned 1 .5 inches distal to the center of a line drawn between the ASIS and the pubic symphysis. 351
ALTERNATIVE POSITIONING LANDMARK An alternative positioning landmark for the pelvis and hip has been described by Bello I I Bello
A : An alternative positioning landmark, 5(70):477, 1 999.
Radiol Technol,
Projections Removed The fol lowing two projections have been removed from this edition of the atlas. Computed tomography (CT) is now com monly used to demonstrate the acetabu lum and special projections of the hip. Plea e ee previou editions of the atla for reference. Hip Axiolateral, Leonard-George Method
•
Acetabulum Axiolateral, Dunlap, Swan on, Penner •
&
SUMMARY OF ANATOMY* Pelvis hlp bones (2) sacrum coccyx pelvic girdle
iliac crest iliac fossa arcuate line auricular surface greater sciatic notch
Hlp bone ilium pubis ischium acetabulum
Pubis body superior ramus inferior ramus
ilium body wing superior spine inferior spine anterior superior lilac spine (ASIS) anterior inferior iliac spine posterior superior lilac spine posterior inferior Iliac spine
Ischium body ischial ramus ischial tuberosity obturator foramen Ischial spine lesser sciatic notch Femur (proximal aspect) head neck body fovea capitis
greater trochanter lesser trochanter intertrochanteric crest Intertrochanteric line
Articulations hip pubic symphysis sacroiliac joints Pelvis brim of the pelvis greater or false pelvis lesser or true pelvis superior aperture or inlet Inferior aperture or outlet pelvic cavity
·See Addendum at the end of the volume for a summary of the changes in the anatomic terms used In this edition.
352
SUM MARY O F PATHOLOGY Condition
Radiographic Finding
Ankylosing Spondylitis
Rheumatoid arthritis variant involving the SI joints and spine
Congenital Hip Dysplasia
Malformation of the acetabulum causing displacement of the Femoral head
Dislocation
Displacement of a bone from the joint space
Fracture
Disruption in the continuity of bone
Legg-Calve-Perthes Disease
Flattening of the femoral head due to vascular interruption
Metastases
Transfer of a cancerous lesion from one area to another
Osteoarthritis or Degenerative Joint Disease
Form of arthritis marked by progressive cartilage deterioration in Synovial joints and vertebrae
Osteopetrosis
Increased density of atypically soft bone
Osteoporosis
Loss of bone density
Paget's Disease
Thick, soft bone marked by bowing and fractures
Slipped Epiphysis
Proximal portion of femur dislocated from distal portion at the proximal epiphysis
Tumor
New tissue growth where cell proliferation is uncontrolled
Chondrosarcoma
Malignant tumor arising from cartilage cells
Multiple Myeloma
Malignant neoplasm of plasma cells Involving the bone marrow and causing de struction of the bone
EXPOSU RE TEC H N IQUE CHART ESSENTIAL PROJ ECTIONS P E LV I S A N D
Part
em
kVp·
Pelvis and U pper Femora-AP*
19
70
Femoral Necks-AP Oblique*
19
Hip-AP*
SID
IR
Dose' (mrad)
200s
t-
48 "
35 x 43 cm
1 35
70
200s
.�
48"
35 x 43 em
1 35
18
65
200s
0.0
48"
24 x 30 em
1 18
Hip-Latera/ (Louenstein-Hiekey) *
18
65
200s
0.0
48"
24 x 30 em
1 18
H i p-Axi%
24
80
48"
24 x 30 em
347
.80
mA
F E MORA
AEC
tero/ (Oone/ius-Miller) §
tm
U PPER
200s
mAs
1 60
Small focal spot. "kVp values are for a 3-phase 1 2-pulse generator. 'Relative doses for comparison use. All doses are skin entrance for average adult at cm indicated. 'Bucky. 16:1 Grid. Screen/Film Speed 300. §Tabletop. 8: 1 Grid. Screen/Film Speed 300.
s,
353
RADI OGRAPHY
.,
.
Radiation Protection
-
,
..
�-.-
0' __
,
-
I
Fig. 7 - 1 3 Female AP pelvis with gonad shield.
Fig. 7 - 1 4 Male AP pelvis with gonad shield.
354
Protection of the patient from unneces ary radiation is a professional responsibility of the radiographer ( ee Chapter I for pe cific guideline ). In this chapter the Shield gonads statement at the end of the Position of parI section indicate that the patient i to be protected from unnece sary radiation by restricting the radiation beam using proper collimation. In addi tion, placing lead shielding between the gonads and the radiation source i appro priate when the clinical objective of the examination are not comprorni ed (Figs. 7- 1 3 and 7- 1 4).
Pelvis and Upper Femora
.. AP PROJECTION Image receptor: 35 x 43 em cross wi e
Position of patient Place the patient on the table in the upine position.
Position of part • Center the midsagittal plane of the body to the rnidline of the grid, and ad j ust it in a true supine position.
• Un Ie s contraindicated because of trauma or pathologic factor , medially rotate the feet and lower l imbs about 1 5 to 20 degrees to place the femoral necks paral lel with the plane of the i mage re ceptor ( l R ) ( Figs. 7- 1 5 and 7- 1 6). Medial rotation i e a i e r for the patient to maintain if the knees are supported. The heels hould be placed about 8 to 1 0 inches (20 to 24 em) apart. • I m mobilize the legs with a sandbag across the ankles, if needed. Check the distance from the ASIS to the tabletop on each side to be sure that the pelvi is not rotated.
B
A
Fig. 7 - 1 5 A, AP pelvis with femoral necks and trochanters poorly positioned because of lateral rotation of the limbs. B, Feet and lower limbs in their natural laterally rotated table top position. causing poor profile of the proximal femora in A.
B
A
Fig. 7 - 1 6 A, AP pelvis with femoral necks and trochanters in correct position. B, Feet and lower limbs medially rotated 1 5 to 20 degrees. correctly placed with the upper femora In correct profile in A. 355
Pelvis and Upper Femora
Center the IR midway between the ASIS and the pubic symphysis. The center of the I R will be about 2 inches (5 cm) in ferior to the ASIS and 2 inche (5 cm) superior to the pubic symphysis i n aver age-sized patients (Fig. 7- 1 7). • I f the pel v i is deep, palpate for the il iac crest and adjust the position of the IR so that its upper border w i l l project I to I Y2 inches (2.5 to 3.8 cm) above the crest.
•
•
•
ShieLd gonads. Respiration: Su pend.
Central ray
Fig. 7 1 7 AP pelvis. -
•
Perpendicular to the midpoint of the I R
A
Iliac crest Ala Anterior superior Iliac spine Sacroiliac Joint Anterior Inferior iliac spine Femoral head
B
Greater trochanter
Obturator foramen Pubic symphysis Lesser trochanter Fig. 7 1 8 A, Male A P pelvis. B, Female A P pelvis. -
356
Pelvis and Upper Femora
Structures shown
Congenital dislocation of the hip
The resulting image shows an AP projec tion of the pelvis and of the head, neck, trochanters, and proximal one third or one fourth of the shaft of the femora (Fig. 7- 1 8).
Martz and Taylorl recommended two AP projections of the pelvis for demonstra tion of the relationship of the femoral head to the acetabulum in patients with congenitaJ dislocation of the hip. The first projection is obtained with the central ray directed perpendicular to the pubic sym physis to detect any lateraJ or superior dis placement of the femoral head. The sec ond projection is obtained with the central ray directed to the pubic symphysis at a cephalic angulation of 45 degrees (Fig. 7 - 1 9). This angulation casts the shadow of an anteriorly displaced femoral head above that of the acetabulum and the shadow of a posteriorly displaced head below that of the acetabulum.
EVALUATION CRITERIA The fol l owing should be clearly demon strated: • Entire pelvis along with the proximal femora • Lesser trochanters, if seen, demon strated on the medial border of the femora • FemoraJ necks in their full extent with out superimposition • Greater trochanters i n profi le • Both i l ia equidistant to the edge of the radiograph • Both greater trochanters equidistant to the edge of the radiograph • Lower vertebraJ column centered to the middle of the radiograph • Symmetric obturator foramina • Ischial spines equally demon trated • Symmetric i l ia aJae • Sacrum and coccyx aligned with the pubic symphysis
' M artz CD, Taylor CC: The 45-degree angle roentgenographic study of the pelvis in congenital dis location of the hip, J BOlle Joilll SLirg 36A:528, 1 954.
.. /.or�/ 'oPo" " oQ •
•
.s::.. • •
Fig. 7 - 1 9 Special projection taken for congenital dis location of the hip.
357
Pelvis and Upper Femora
LATERAL PROJECTION Right or left position Image receptor: 35 x 43 cm length wi e
Position of patient • Place the patient in the lateral recumbent, dol' al decubitu , or upright position.
Position of part Recumbent position • When the patient can be placed in the lat eral position, center the midcoronal plane of the body to the midline of the grid. • Extend the thighs enough to prevent the femora from obscuring the pubic arch. • Place a support under the lumbar spine, and adjust it to place the vertebral col umn parallel with the tabletop ( Fig. 7-20). If the vertebral column i al lowed to sag, it will tilt the pelvis in the longitudinal plane.
• Adj u t the pelvis in a true lateral posi tion, with the ASISs lying i n the same vertical plane. • Place one knee directly over the other knee. A pillow or other support between the knees promote tabilization and pa tient comfort. • Berkebile, Fi cher, and Albrecht' recom mended a dorsal decubitu lateral projec tion of the pelvis for demon tration of the "gull-wing sign" in case of fracture dis location of the acetabular rim and poste rior dislocation of the femoral head. ' Berkebile RD, Fischer DL, Albrecht LF: The gull wing sign: value of the lateral view of the pelvi in fracture di location of the acetabular rim and po te rior dislocation of the femoral head, Radiology 84:937. 1 965.
Fig. 7-20 Lateral pelvis.
358
Pelvis and Upper Femora
•
•
•
•
•
•
Upright position Place the patient in the lateral position i n front of a vertical grid device, and center the midcoronal plane of the body to the midl ine of the grid. Have the patient stand straight, with the weight of the body equal ly distributed on the feet 0 that the midsagittal plane i paral lel with the plane of the J R . If the l i m b are o f unequal length, place a support of suitable height under the foot of the short side. Have the patient grasp the side of the tand for upport.
Shield gonads. Respiration: Suspend.
Central ray •
•
EVALUATION CRITERIA
Perpendicular to a point centered at the level of the oft tissue depression j ust above the greater trochanter (approxi mately 2 i nches [5 cm]) and to the mid point of the i mage receptor Center the IR to the central ray
COMPUTED RADIOGRAPHY
�
The higher kilovolt (peak) ( kVp) used for this projection requires that the col li ma tion be very close. Scattered and primary radiation reaching the IP phosphor may cause computer artifacts.
The following should be clearly demon strated : • Entire pelvi and the proxi mal femora. • Sacrum and coccyx. • Superimpo ed posterior margins of the ischium and ilium. • Superimpo ed femora. • Superimposed acetabular shadow . The larger circle of the fo sa (farther from the IR) will be equidi stant from the smaller circle of the fossa nearer the IR throughout their circumference. • Pubic arch unobscured by the femora.
Structures shown The resulting image shows a lateral radi ograph of the lumbosacral junction, sacrum, coccyx, and uperimpo ed hlp bones and upper femora (Fig. 7-2 1 ).
Lumbosacral joint Sacrum
Femoral heads (superimposed)
Ischial tuberosities
Fig. 7-21 Lateral pelvis.
359
Pelvis and Hip Joints
AXIAL PROJECTION C HASSARD-LA P I N E M ETHOD! hassard and Lapine! devised this method for the purpose of mea uring the horizon tal, or biischial, diameter in pelvimetry. Some radiographers u e thi method to de termine the relationship of the femoral head to the acetabu lum, and others employ it to demon trate the opacified recto ig moid portion of the colon. 'Chassard, Lapine: E lude radiographique de I'arcade pubienne chez Ia femme enceinte; une nouvelle methode d' appreciation du diametre bi-ischiatique, J Radiol Electrol 7: 1 1 3 , 1 923.
NOTE: This examination is contraindicated for patients with a suspected fracture or pathologic condition.
Position of part •
Image receptor: 35 x 43 cm cro s wise
Position of patient Seat the patient well back on the end or ide of the radiographic table so that the posterior urface of the knees is in contact with the edge of the table.
•
•
•
•
•
Fig. 7-22 Axial pelvis.
360
If the patient i seated at the ide of the table, place the longitudinal axi of the I R perpendicular to the mid agittal plane. I f the patient i eated on the end of the table, center the midsagittal plane of the body to the midline of the grid. If needed, place a stool or other suitable upport under the feet (Fig. 7-22). To prevent the thighs from l i m i ting flexion of the body too greatly, have the patient abduct them as far as the end of the table permjt . I nstruct the patient to lean directly for ward until the pubic symphysis is i n close contact w i t h the table; the vertical axi of the pel v i w i l l be tilted forward approximately 45 degrees. The average patient can achieve this degree of flex ion without strain. Have the patient grasp the ankle to aid i n maintai ning the position.
ShieLd gonads. Respiration: Su pend.
Pelvis and Hip Joints
Central ray •
•
Perpendicular through the lumbosacral region at the level of the greater trochanter . When flexion of the body is restricted, direct the central ray anteriorly, perpen dicular to the coronal plane of the pubic symphysis.
Structures shown The resulting i mage shows an axial pro jection of the pelvis, demonstrati ng the re lationship between the femoral heads and the acetabula, the pelvic bones, and any opacified structure within the pelvis (Fig.
7-23).
EVALUATION CRITERIA The fol l owing should be clearly demon strated: • Femoral head and acetabula • Entire pelvis along with the proximal femora • Symmetric hip bones • Greater trochanters equidistant to the sacrum
Femoral body Ala
Acetabulum
Femoral head
Greater trochanter Ischial tuberosity
Sacrum
Fig. 7-23 Axial pelvis.
36 1
Femoral Necks
.. AP OBLIQUE PROJECTION MODIFIED C LE AVES M ETHOD
Position of patient o
Bilateral projection
Place the patient in the supine po ition. o
Image receptor: 35 x 43 cm cross
Position of part
wise This projection is often called the bilateral "frog leg" posi tion. NOTE: Thi examination is contraindicated for the patient suspected of ha ing a fracture or other pathologic disease.
o
o
o
Center the mid agittal plane of the body to the midli ne of the grid. Flex the patient's elbows, and rest the hands on the upper chest. Adjust the patient 0 that the pelvis is not rotated. This can be achieved by placing the two ASISs equidistant from the radiographic table. Place a compression band acros the patient well above the hip joints for sta bility, if needed.
o
o
o
o o
o
Step 1 Have the patient flex the hip and knees and draw the feet up as much a po i ble ( i.e., enough to place the femora i n a nearly vertical p o ition if the affected ide permits). I n truct the patient to hold this position, which is relatively comfortable, while the x-ray tube and I R are adju ted. Step 2 Center the I R I inch (2.5 cm) superior to the pubic ymphysis. Step 3 Abduct the thighs as much as possible, and have the patient turn the feet inward to brace the ole again t each other for support. According to Cleave , the an gle may vary between 25 and 45 de grees, depending on how vertical the femora can be placed. Center the feet to the midline of the grid (Fig. 7-24). If possible, abduct the thighs approxi mately 45 degrees from the vertical plane to place the long axe of the femoral neck parallel with the plane of the I R . Check the position o f the thighs, being careful to abduct them to the arne degree.
Unilateral projection o
Fig. 7-24 AP oblique femoral necks with perpendicular central ray: modified Cleaves method.
o
o
o
o
Fig. 7-25 Unilateral AP oblique femoral neck: modified Cleaves method. 362
Adj u t the body position to center the ASIS of the affected ide to the midl i ne of the grid. Have the patient flex the hip and knee of the affected side and draw the foot up to the oppo ite knee a much a po sible. After adj usting the perpendicul ar cen tral ray and positioning the IR tray, have the patient brace the ole of the foot against the opposite knee and abduct the thigh lateral l y approxi mately 45 degrees (Fig. 7-25). The pelvis may rotate l ightly.
Shield gonads. Respiration: Suspend.
Femoral Necks
Central ray •
Perpendicular to enter the patient's mjdsagittal plane at the level I inch (2.5 cm) superior to the pubic symphy sis. For the uni lateral position, direct the central ray to the femoral neck ( ee Fig. 7- 1 2).
Structures shown The bi lateral resulting image hows an AP oblique projection of the femoral heads, necks, and trochanteric areas projected onto one radiograph for comparison ( Figs. 7-26 to 7-28).
EVALUATION CRITERIA The fol lowing should be clearly demon strated: • 0 rotation of the pelvis, as evidenced by a symmetric appearance. • Acetabulum, femoral head, and femoral neck. • Lesser trochanter on the medial side of the femur. • Femoral neck without superi mposition by the greater trochanter. Excess ab duction cau es the greater trochanter to obstruct the neck. • Femoral axes extended from the hip bone at equal angles.
Fig. 7-26 AP femoral necks. Note the fixation device in the right hip, as well as the male gonad shield.
Femoral head Femoral neck
Greater trochanter
Lesser trochanter
Fig. 7-27 AP oblique femoral necks: modified Cleaves method (same patient as in Fig. 7-26).
363 Fig. 7-28 AP oblique femoral neck: modified Cleaves method.
Femoral Necks
AXIOLATERAL PROJECTION
Position of patient
ORIGINAL C LEAVES METHOD'
•
NOTE: Thi examination i contraindicated for patient with u pected fracture or pathologic condition.
Image receptor: 35 x 43 cm cro s wi e
Place the patient in the supine position.
Position of part NOTE: This is the arne part position as the modified Cleaves method previollsly described. The projection can be performed unilaterally or bilaterally.
'Cleaves EN: Ob ervations on lateral views of the hip. Am J Roelllgell 34:964. 1 938.
•
•
•
Central ray Parallel with the femoral shafts. Accordjng to Cleaves, I the angle may vary between 25 and 45 degrees, dependjng on how ver tical the femora can be placed. 'Cleaves EN: Observations on lateral views of the hip, Am J Roelllgell 34:964, 1 938.
Before having the patient abduct the thighs (described in step 3 on p. 362), direct the x-ray tube parallel to the long axes of the femoral shaft (Fig. 7-29). Adjust the IR so the midpoint coincides with the central ray.
Shield gonads. Respiration: Suspend.
Fig. 7-29 Axiolateral femoral necks: Cleaves method .
364
Femoral Necks
Structures shown The resulting i mage shows an axiolateral projection of the femoral heads, necks, and trochanteric areas ( Fig. 7-30).
EVALUATION CRITERIA The fol lowing hould be clearly demon trated: • Axiolateral projections of the femoral neck • Femoral necks without overlap from the greater trochanter
Congenital dislocation of the hip
• Small parts of the Ie ser trochanters on •
• • •
the posterior surfaces of the femur Small amount of the greater trochanters on both the posterior and anterior sur faces of the femurs Both sides equidistant from the edge of the radiograph Greater amount of the proxi mal femur on a unilateral examination Femoral neck angles approximately 1 5 to 20 degree superior to the femoral bodies.
The diagnosis of congenjtal djslocation of the hip in newborns has been discussed in numerous articles. Andren and von Ro en! described a method based on certain theo retic considerations. Their method requires accurate and judicious application of the positioning technique to make an accurate diagnosis. The Andren-von Ro en approach involves taking a bi lateral hip projection with both legs forcibly abducted to at lea t 45 degrees with appreciable inward rotation of the femora. Knake and Kuhns2 described the construction of a device that control led the degree of abduction and rotation of both limbs. They reported that the device essen tially eliminated and greatl y simplified the positioning difficulties, thereby reducing the number of repeat examinations.
A
' Andren L, von Rosen S: The diagnosis of disloca tion of the hip in newboms and the primary results of immediate treatment, ACla RadioI 49:89, 1 958. 'Knake lE, Kuhn LR: A device to aid in positioning for the Andren-von Ro en hip v iew, Radiology
Femoral head
1 1 7 : 735, 1 975.
Femoral head within acetabulum Femoral neck
Greater trochanter ------011 Lesser trochanter ---
B
c
Fig. 7-30 Axiolateral femoral necks: Cleaves method. A, Bilateral examination. B and C, U nilateral hip examination of a patient who fell. No fractures were seen on the initial AP hip radiograph (B), and a second projection using the Cleaves method was performed.
A
chip fracture of the femoral head (arrow) was seen (C). At least two projections are
required in trauma diagnoses.
365
Hip
.. AP PROJECTION
•
Image receptor: 24 x 30 cm length wise
Position of patient •
Central ray
Position of part
•
Place the patient in the upine position. •
•
•
Adj ust the patient's pelvis so it is not rotated. This is accomplished by plac ing the ASISs equidistant from the table (Figs. 7-3 1 and 7-32). Place the patient's arms in a comfort able position. Medial ly rotate the lower l i mb and foot approximately 1 5 to 20 degrees to place the femoral neck parallel with the plane of the I R , unless this maneuver is con traindicated or other instructions are given . Place a support under the knee and a sandbag acro the ankle. This makes it easier for the patient to maintain this position.
Perpendicular to the femoral neck. Using the localizing technique previ ou ly described (see Fig. 7- 1 2), place the central ray approximately 2 � i nches (6.4 cm) distal on a l ine drawn perpen dicular to the midpoint of a l i ne be tween the AS IS and the pubic symph ysis. Center the I R to the central ray. Make any necessary adju tments in the IR size and central ray point when an entire orthopedic device is to be shown on one image.
•
•
•
Shield gonads. Respiration: Suspend.
,
,
\
\
\
\
Fig. 7-31 AP hip.
366
Fig. 7-32 AP hip.
Hip
Structures shown
EVALUATION CRITERIA
The re ulting i mage shows the head, neck, trochanters, and proximal one third of the body of the femur (Fig. 7-33). I n the initial examination of a hip le sion, whether traumatic or pathologic i n origin, the A P projection i s often obtained using an i mage receptor large enough to i nc lude the entire pel vic girdle and upper femora. Progress studies may be restricted to the affected side.
The fol lowing should be clearly demon strated: • Femoral head, penetrated and seen through the acetabulum. • Regions of the ilium and pubic bones adjoining the pubic symphysis. • Any orthopedic appliance in its entirety. • Hip joint. • Greater trochanter in profi le. • Entire long axis of the femoral neck not foreshortened.
• Proxi mal one third of the femur.
• Lesser trochanter is usually not pro
jected beyond the medial border of the femur, or only a very small amount of the trochanter is een .
NOTE: Trauma patients who have sustai ned se vere injury are not usually tran ferred to the ra diographic table but are radiographed on the stretcher or bed. After the localization point has been e tablished and marked, one assistant should be on each side of the stretcher to grasp the sheet and lift the pelvis just enough for placement of the I R while a third per on sup ports the injured limb. Any necessary manipu lation of the limb must be made by a physician.
Ilium
Acetabulum
Femoral head
Greater trochanter Femoral neck Pubic symphysis Lesser trochanter Femoral body Fig. 7-33 AP hip.
367
Hip
.. LATERAL PROJECTION Mediolateral LAUE NSTEI N A N D H IC KEY METHODS NOTE: This examination i contraindicated for patient with a su pected fracture or pathologic condition.
Position of part
Structures shown
• Adjust the patient's body, and center the affected hip to the midline of the grid. • A k the patient to flex the affected knee and draw the thigh up to a position at nearly a right angle to the hip bone. Keep the body of the affected femur parallel to the table. Extend the oppo ite limb and support it at hip level and under the knee. • Rotate the pelvi no more than neces ary to accommodate flexion of the thigh and to avoid superimposition of the affected side ( Fig. 7-34).
The resulting i mage show a lateral pro jection of the hip, including the acetabu lum, the prollimal end of the femur, and the relationship of the femoral head to the acetabul u m (see Figs. 7-35 and 7-36).
•
The Lauenstein and H ickey method are u ed to demonstrate the hip joint and the relation hip of the femoral head to the ac etabulum. This position is similar to the previously described modified Cleave method.
Image receptor: 24 x 30 cm cros wise
Position of patient • From the upine po ition, rotate the pa tient l ightly toward the affected ide to an oblique position. The degree of obl iquity w i l l depend on how much the patient can abduct the leg.
•
•
•
Shield gonads. Respiration: Suspend.
Central ray Perpendicular through the hip joint, which i located midway between the ASIS and the pubic symphysis for the Lauenstein method (Fig. 7-35) and at a cephalic angle of 20 to 25 degree for the H ickey method ( Fig. 7-36). • Center the IR to the central ray.
•
Fig. 7-34 Mediolateral hip: Lauenstein method.
368
EVALUATION CRITERIA The following should be clearly demon strated: • H i p joint centered to the radiograph • H i p joint, acetabulum, and femoral head • Femoral neck overlapped by the greater trochanter in the Lauenstein method • With cephalic angulation in the H ickey method, the femoral neck free of uper i mposition
Hip
B
A
Acetabulum
Femoral head
Femoral neck
Lesser trochanter Ischial tuberosity
Fig. 7-35 A. Mediolateral hip with perpendicular central ray: Lauenstein method. B. Mediolateral hip with perpendicular central ray using male gonad (contact) shield.
Fig. 7-36 Mediolateral hip with 20-degree cephalad angulation: Hickey method.
369
Hip
'" AXIOLATERAL PROJECTION DAN E LIUS-MILLER METHOD
Position of part o
Image receptor: 24 x 30 cm lengthwise
Position of patient o
Place the patient in the upine po ition.
o
o
When examjnjng a patient who is thin or who i s lying on a soft bed, elevate the pelvis on a firm pil low or folded heet sufficiently to center the most prorru nent point of the greater trochanter to the midline of the l R . The support must not extend beyond the lateral surface of the body; otherwise it w i l l interfere with the placement of the I R . When the pelvis i elevated, support the affected limb at hip level on sandbags or firm pillows.
o
o
Flex the knee and hip of the unaffected side to elevate the thigh in a vertical po sition. Rest the unaffected leg on a suitable upport that w i l l not i nterfere with the central ray. Special support device are avrulable. Adj ust the pelvis so that it is not rotated (Fig . 7-37 and 7-38). Vnle contrrundicated, gra p the heel and medially rotate the foot and lower limb of the affected side about 1 5 or 20 degrees. A andbag may be u ed to hold the leg and foot in this po ition, and a small support can be placed under the knee. The manipulation of patients with unhealed fractures should be performed by a physician.
A
B
Fig . 7-37 A, Axiolateral hip: Danelius-Milier method, IR supported with sandbags. B, Same projection, patient holding IR. Note that the foot is on a footrest.
370
Fig. 7-38 Axiolateral hip: Danelius-Milier method.
Hip
Position of IR
•
•
•
•
•
Place the I R in the vertical position with its upper border i n the crease above the il iac crest. Angle the lower border away from the body until the IR is exactly parallel with the long axis of the femoral neck. Support the IR in this position with sandbags or a vertical IR holder. These are the preferred methods. Alternatively, the patient may support the IR with the hand. Be careful to position the grid so that the lead strips are in the horizontal po ition.
Shield gonads. Respiration: Suspend.
Structures shown
Central ray Perpendicular to the long axis of the femoral neck. The central ray enters midthigh and passe through the femoral neck about 2 Y2 i nches (6.4 cm) below the point of intersection of the localization l i nes described previously (see Fig. 7- 1 2) .
COMPUTED RADIOGRAPHY
•
Both dense and nondense body areas w i l l b e exposed. The k V p must b e sufficient to penetrate the dense area. Col l i mation must be very clo e to keep unnecessary radiation from reaching the I P phosphor.
The resulting image hows the acetabu lum, head, neck, and trochanters of the fe mur ( Fig. 7-39).
EVALUATION CRITERIA The following hould be clearly demon strated: • Femoral neck without overlap from the greater trochanter • Small amount of the lesser trochanter on the posterior surface of the femur • Small amount of the greater trochanter on the anterior and posterior surfaces of the prox imal femur when the femur is properly inverted • Soft tissue shadow of the unaffected thigh not overlapping the hip joint or proximal femur • Hip joint with the acetabulum • Any orthopedic appliance in its entirety • Ischial tubero ity below the femoral head
Acetabulum
Femoral head Femoral neck Greater trochanter Lesser trochanter
Fig. 7-39 Axiolateral hip: Danelius-Miller method.
371
Hip
AXIOLATERAL PROJECTION
Image receptor: 24 x 30 cm
CLEM ENTS-N AKAYAMA MODIFICATION l
Position of patient
When the patient ha bilateral hip frac tures, bilateral hip arthroplasty (plastic urgery of the hip joints), or limitation of movement of the u naffected leg, the Danel i us-M i l ler method cannot be used. Clements and Nakayama' described a modification using a I S-degree posterior angulation of the central ray (Fig. 7-40). 'Clements RS, Nakayama HK: Radiographic meth ods in total hip arthroplasty, Radiol Technol 5 1 :589, 1 980.
Position of part •
•
Position the patient supine on the radio graphic table with the affected side near the edge of the table.
•
•
•
•
For this position, do not rotate the lower limb i nternally. Instead, the limb remains i n a neutral or l ightly exter nally rotated position. Support a grid IR on the B ucky tray so that its lower margin is below the pa tient. Position the grid so the l i ne run parallel with the floor. Adj ust the grid parallel to the axis of the femoral neck and tilt it top back 1 5 degrees.
Shield gonads. Respiration: Suspend.
Fig. 7-40 Axiolateral hip: Clements-Nakayama method.
372
Hip
Central ray
Structures shown
• Directed 1 5 degrees posteriorly and aligned perpendicular to the femoral neck and grid I R
This leg position demonstrates a lateral hip image because the central ray is an gled 1 5 degrees posterior instead of the toes being medially rotated. The resulting i mage shows the acetabulum and the proximal femur, including the head, neck, and trochanters in lateral profile. The C lements-Nakayama modification (Fig. 7-4 1 ) can be compared to the Dane lius M i l ler approach described previously (Fig. 7-42).
Fig. 7-41 Clements-Nakayama method with I S-degree central ray angulation in the same patient as in Fig. 7-42.
EVALUATION CRITERIA The fol l owing should be clearly demon strated: • H i p joint with the acetabu lum • Femoral head, neck, and trochanter • Any orthopedic appliance in its entirety
Fig. 7-42 Postoperative Danelius-Miller method used for a patient who was unable to ftex the unaffected hip. The contralateral thigh (arrows) is obscuring the femoral head and acetabular area.
373
Hip
AXIOLATERAL PROJECTION FRIEDMAN METHOD NOTE: This examination is contraindicated for patients with a suspected fracture or pathologic condition.
Image receptor: 24 x 30 cm length wise
Position of patient
o
Have the patient l ie in the lateral re cumbent position on the affected ide. Center the midcoronal plane of the body to the midline of the radiographic table.
Position of part o
Fig. 7-43 Axiolateral hip with central ray angulation of 35 degrees: Friedman method.
o
o
o
o
Acetabulum
Femoral head
Femoral neck Greater trochanter
Ischial tuberosity
Lesser trochanter Femoral body
Fig. 7-44 Axiolateral hip with central ray angulation of 35 degrees: Friedman method.
374
Extend the affected limb and adjust it in a lateral po ition. Roll the upper side of the patient's limb gently posteriorly, approximately 1 0 de grees, and place a upport under the knee to support it at hip level. The af fected femur does not change position if it is properly immobilized; the pelvis ro tates from the femoral head (Fig. 7-43). With the IR in the Bucky tray, adj u t its position so that the midpoint of the I R coincide with the central ray.
ShieLd gonads. Respiration: Suspend.
Hip
Central ray •
Directed to the femoral neck at an angle of 35 degrees cephalad (Figs. 7-44 and
7-45 ). •
Kisch I recommended that the central ray be angled 1 5 or 20 degrees cephalad for this position ( Fig. 7-46).
EVALUATION CRITERIA The following should be clearly demon strated: • Moderatel y d i storted femoral head, neck, and trochanters because of the an gulation of the x-ray beam • Hip joint
Structures shown The resulting i mage shows an axiolateral projection of the head, neck, trochanters, and proximal body (shaft) of the femur. ' Kisch E: Eine neue Methode fiir rontgenolische Darstellung des Hiiftgelenks in frontaler Ebene. FO/'lschr RoelllgelJstr 27 : 309. 1 920
Fig. 7-45 Axiolateral hip showing bone anatomy.
Fig. 7-46 Axiolateral hip with central ray angulation of 20 degrees: Friedman method.
375
Hip
PA OBLIQUE PROJECTION
Position of part
HSIEH METHOD1 RAO or LAO position Hsieh I recommended thi projection for demon trating po terior di locations of the femoral head in ca es other than acute fracture dislocations.
o
Image receptor: 24 x 30 cm length wi e
Position of patient o
Place the patient with a u pected po terior hip dislocation in the emiprone po ition, and center the affected hip to the midline of the radiographic table.
' Hsieh CK: Posterior dislocation of the hip. Radiology 27:450. 1 936.
o
o
Elevate the unaffected side approxi mately 40 to 45 degrees and have the patient support the body on the flexed knee and forearm of the elevated ide. Adju t the position of the body to place the posterior surface of the affected il iac bone over the midl ine of the grid (Fig. 7-47). With the I R in the B ucky tray, adjust it position so that the center of the I R will lie at the level of the superior border of the greater trochanter.
Shield gonads. Respiration: Su pend.
Central ray o
Perpendicular to the midpoint of the I R pas i n g between the posterior surface of the iliac blade and the dislocated femoral head
Structures shown The resulting image show a PA oblique projection of the ilium, hip joint, and proximal femur ( Figs. 7-48 and 7-49).
EVALUATION CRITERIA The following should be clearly demontrated: • Hip joint near the center of the radiograph • Acetabul u m and femoral head • Superimposed soft tissue of buttock over the area of the femoral neck • Uristl recommended a right or left pos terior oblique position (AP projection) for demonstration of the po terior rim of the acetabulum in acute fracture dislocation injuries of the hip. For this projection, the patient is adj usted from the upine position. The injured hip i elevated 60 degrees to place the poste rior rim of the acetabulum in profile, and the body is adju ted to center the sagittal plane pa sing through the ASIS to the midline of the table. The I R is centered at the level of the upper border of the greater trochanter. The central ray is directed perpendicular to the mid point of the IR (Figs. 7-50 and 7-5 \ ). 'Urist MR: Fracture-di location of the hip joint, 30A:699. 1 948.
J Bone Join! 5l/rg
Fig. 7-47 PA oblique hip, LAO position: Hsieh method.
376
Hip
Acetabulum
Femoral head Femoral neck
Greater trochanter Gluteal soft tissue
Fig. 7-48 PA oblique hip: Hsieh method . No dislocation is seen.
Fig. 7-49 PA oblique hip showing bone anatomy.
Ilium
Acetabulum
Femoral head
Greater trochanter Ischium Femur
Fig. 7-50 AP oblique hip with 60-degree rotation: Urlst method.
Fig. 7-51 AP oblique hip showing bone anatomy.
377
Hip
MEDIOLATERAL OBLIQUE PROJECTION
Position of part •
LlLIENFELD METHOD
RAO or LAO position
•
NOTE: This examination is contraindicated for patients with a suspected fracture or pathologic condition.
•
Image receptor: 24 X 30 cm length wi e •
Position of patient •
Have the patient l ie in the lateral re cumbent position on the affected ide. •
•
•
Center the midcoronal plane of the body to the midline of the grid. Fully extend the affected thigh, adjust it i n a true lateral position, and immobi l ize it with sandbags. Roll the upper side gently forward ap proximately 1 5 degrees or just enough to separate the two ides of the pelvis. Support the limb at hip level on sandbags. If the affected ide is well immobilized and the upper side is gently rolled for ward, the affected hip will not change po ition; the pelvi will rotate from the femoral head (Fig. 7-52). With the I R in the Bucky tray, adjust its position so that the center point of the I R l ies at the level of the greater trochanter.
Shield gonads. Respiration: Suspend.
Central ray •
Perpendicular to the midpoint of the JR, traversing the affected hip joint
Structures shown The resulting i mage shows a mediolateral oblique projection of the ilium, acetabu lum, and proxi mal femur ( Fig. 7-53).
EVALUATION CRITERIA The following should be clearly demon strated: • Hip joint near the center of the radio graph • Femoral head and acetabulum • Unaffected hip and acetabul u m not overlapping the same tructures of the ide of interest NOTE: Because the Lilienfeld projection i not used with patients who have an acute hip injury, these patients can be comfortably, safely, and atisfactorily examined in the po ition de cribed by Colonna.' Positioning is approximately the same as for the Lilienfeld method except that the patient is placed 011 the unaffected side and adjusted to center the uppennost hip to the mid line of the radiographic table. Colonna recom mended that the uppemlost ide-the affected side-be rotated about 1 7 degree anteriorly from the true lateral position. He tated that this degree of rotation separate the shadows of the hip joints and gives the optimum projection of the lope of the acetabular roof and the depth of the socket (Fig. 7-54). A imilar position, the "Fal e Profile" posi tion i used to demonstrate the anterior acetabu lar roof. See the Merrill's website for further information. 'Colonna PC: A diagnostic roentgen iew of the ac etabulum. 511rg Ciill Nortll Am 33: 1 565, 1 953.
Fig. 7-52 Mediolateral oblique hip, LAO position: Lilienfeld method.
378
Hip
Iliac crest Acetabulum Femoral head Greater trochanter Ischium
Ischium (of elevated side) Fig. 7-53 Mediolateral oblique hip: Lilienfeld method demonstrating left hip.
Fig. 7-54 Colonna method of patient positioning. demonstrating elevated right hip.
379
Acetabulum
PA AXIAL OBLIQUE PROJECTION TEUFEL M ETHOD RAO or LAO position
Image receptor: 8 x 1 0 i nch ( 1 8 X 24 cm) lengthwise Position of patient
o
Have the patient lie in a semi prone po sition on the affected side.
Position of part
o
o o o
Align the body, and center the hip being exami ned to the midline of the grid. Elevate the unaffected side so that the anterior surface of the body forms a 38degree angle from the table (Fig. 7-55) . Have the patient upport the body on the forearm and flexed knee of the ele vated side. With the IR in the Bucky tray, adju t the po ition of the 1 R 0 that it mid point coincides with the central ray.
o Shield gonads. o
�w-��J
Respiration: Su pend.
7
;.�. . Fig. 7-55 PA axial oblique acetabulum: Teufel method.
380
�
Acetabulum
Central ray •
EVALUATION CRITERIA
Directed through the acetabulum at an angle of 1 2 degree cephalad. The cen tral ray enter the body at the i nferior level of the coccyx and approximately 2 inche (5 cm) lateral to the m idsagittal plane toward the side being examined.
Structures shown
The fol l ow i ng should be clearly demon strated: • Hip joint and acetabul um near the cen ter of the radiograph • Femoral head in profile to show the concave area of the fovea capitis • Superoposterior wall of the acetabu lum
The resulting i mage shows the fovea capi ti and particularly the superoposterior wall of the acetabulum (Fig. 7-56).
Acetabulum
Fovea capitis
Femoral head Femoral neck
Greater trochanter Ischium
Fig. 7-56 PA axial oblique acetabulum: Teufel method.
381
Acetabulum
AP OBLIQUE PROJECTION
Position of patient
Acetabulum JUDET METHODl RPO or LPO position
•
J udet, l udet, and Letournel described two 45-degree posterior oblique positions that are useful in diagnosing fracture of the acetabulum: the i nternal oblique po ition (affected side up) and the external oblique po ition (affected ide down).
Image receptor: 24 x 30 Col length wise
Place the patient in a semisupine po i lion with the affected hip up.
Position of part •
•
•
Al ign the body, and center the hip being exami ned to the middle of the I R . Elevate t h e affected side so that the anterior surface of the body form a 45 degree angle from the table ( Fig. 7-57, A ).
Shield gonads. Respiration: Suspend.
Central ray
Internal oblique: For a patient with a suspected fracture of the il iopubic column2 (anterior) and the posterior rim of the acetabulum
Perpendicular to the IR and entering 2 inche inferior to the ASIS of the af fected side
'Judet R, Judet J, Letoumel E: Fractures of the ac etabulum: classification and surgical approaches for open reduction, J BOlle Joilll 511rg 46A: 1 6 1 5 , 1 964. '/Iiopllbic COIIlIllIl (anterior)--composed of a shon egment of the ilium and the pubis and extend up as far as the anterior spine of the ilium and extends from the symphysi pubis and obturator foramen through acetabulum to ASIS
Acetabulum
A
ANTERIOR
ANTERIOR Acetabulum 45'
support "
Fig. 7-57 A, AP oblique projection. Judet method for the right hip. This LPO places the right hip in the internal oblique position. B, AP oblique projection. Judet method for the right hip. This RPO places the right hip in the external oblique position.
382
B
Acetabulum
External oblique:
Central ray
For a patient with a suspected fracture of the i l ioischial column I ( posterior) and the anterior rim of the acetabulum
Position of patient •
Place the patient in a semisupine posi tion with the affected hip down.
•
•
•
Align the body, and center the hip being exami ned to the middle of the I R . Elevate the affected side so that the ante rior surface of the body fon11S a 45 degree angle from the table ( Fig. 7-57, 8).
Shield gonads. Respiration: Suspend.
' llioischial COILlIIIII
( posterior)-composed of the vertical portion of the ischium and the portion of the ilium immediately above the ischium and extends from the obturator foramen through the posterior as pect of the acetabulum
NOTE: Rafert and Long' describe a modifica tion of the ludet method on trauma patients.
Perpendicular to the IR and entering at the pubic symphysis
RESEARCH: Catherine E. Hearty, MS, RT( R) performed the research and provided this new projection for this edition of the atlas.
Structures shown The resulting i mage shows the acetabular rim ( Fig. 7-58).
EVALUATION CRITERIA
Position of part •
•
'Rafert JA, Long BW: Showing acetabular trauma with more clarity, less pain, Radial Technol 63: 93, 1 99 1 .
The following should be clearly demon strated: • Acetabulum should be centered to the I R. • The i l iopubic column and the posterior ri m of the affected acetabulum are seen on the internal oblique. • The i l ioischial column and the anterior ri m of the acetabulum are seen on the external obl ique.
B
A
Fig. 7-58 AP oblique projection, Judet method, right hip. A, LPO, B, RPO.
(From Long BW, Rafert JA: Orthopaedic radiography, Philadelphia, 1995. Saunders.)
383
Anterior Pelvic Bones
PA PROJECTION Image receptor: 8 x 1 0 i nch ( 1 8 X 24 cm) cross wi e
Position of patient •
Place the patient in the prone position, and center the midsagittal plane of the body to the midline of the grid.
Position of part •
•
•
•
Sacrum
Coccyx
Acetabulum
Femoral head Superior pubic ramus Obturator foramen Pubic symphysis
Inferior pubic ramus Ischial tuberosity
384
Shield gonads. Respiration: Suspend.
Central ray
Fig. 7-59 PA pelvic bones.
Fig. 7-60 PA pelvic bones.
With the lR in the Bucky tray, center the IR at the level of the greater trochanters. This positioning aI 0 center the I R to the pubic ymphysis (Fig. 7-59).
Perpendicular to the midpoint of the I R. The central ray enters the distal coccyx and exits the pubic symphysis.
Structures shown The resulting image shows a PA projection of the pubic symphysis and ischia, includ ing the obturator foramina (Fig. 7-60).
EVALUATION CRITERIA The fol lowing should be clearly demon strated: • Pubic and ischial bones not magnified or superimposing the acrum or coccyx • Pubic and ischial bones near the center of the radiograph • H i p joints • Symmetric obturator foramina
Anterior Pelvic Bones
AP AXIAL "OUTLET" PROJECTION TAYLOR METHODl
Image receptor: 24 x 30 cm cross wise
Position ot patient • Place the patient in the supine po ition.
Position of part • Center the midsagittal plane of the pa tient's body to the midl i ne of the grid, and adj ust the pelvis so that it is not ro tated. The ASISs should be equidi stant from the table ( Fig. 7-6 1 ). • With the I R in the Bucky tray, adjust the tray 's position so the midpoint of the I R will coincide w i t h the central ray. • Shield gonads. • Respiration: Suspend.
Fig. 7-61 AP axial pelvic bones: Taylor method.
Ilium
Central ray
Acetabulum
Males • Directed 20 to 35 degrees cephalad and centered to a point 2 inches (5 cm) di tal to the superior border of the pubic symphysis. Females • Directed 30 to 45 degrees cephalad and centered to a point 2 i nches (5 cm) dis tal to the upper border of the pubic symphy is.
Superior pubic ramus Femoral head
-=-"--=----==-::"1 Pubic symphysis
Obturator foramen Inferior pubic ramus
Ischial ramus
Structures shown The resulting image hows the rami with out the fore hortening seen i n a PA or AP projection (due to the CR more perpen dicular to the rami ( Figs. 7-62 and 7-63 ).
EVALUATION CRITERIA The fol lowing should be clearly demon strated: • Pubic and ischial bone magnified with pubic bones superimposed over the sacrum and coccyx • Symmetric obturator foramina • Pubic and ischial rami near the center of the radiograph • Hip joints
Fig. 7-62 Male AP axial pelvic bones: Taylor method.
Gonadal shield
'Taylor. R : Modified anteroposterior projection of the anterior bones of the pel vi . Radiog Ciin Photog 1 7:67, 1 94 1 .
Fig. 7-63 Female AP axial pelvic bones: Taylor method. 385
Anterior Pelvic Bones
SUPEROINFERIOR AXIAL "INLET" PROJECTION
Position of part •
LlLIE NFELD M ETHOD1 •
Image receptor: 8 x 10 inch ( 1 8 X 24 cm) crosswi e
Position of patient Place the patient on the radiographic table in a eated-upright position. •
'Lilienfeld L: Die axiale Aufughrne der Regio pu bien. FOr/scllr Roelllgellstr 24:285. 1 9 1 8- 1 9 1 9.
Center the midsagittal plane of the pa tient's body to the midline of the grid. Flex the knees s lightly and support them to relieve strain . If the travel of the IR tray is great enough to permit centering near the end of the table, have the patient it 0 that the legs can hang over and the feet can rest on a suitable support. Adjust the pelvis so that the ASISs are equidistant from the table.
•
•
Have the patient extend the arm for support, lean backward 45 or 50 de gree , and then arch the back, if pos i ble, to place the pubic arch in a vertical position ( Fig. 7-64). With the IR in the B ucky tray, center it at the level of the greater trochanter .
• Shield gonads. Respiration: Suspend.
Central ray • Perpendicular to the midpoint of the im age receptor and entering I � inche (3.8 cm) superior to the pubic symphysi
Structures shown The resulting i mage hows a uperoinfe rior axial projection of the anterior pubic and ischial bone and the pubic ymphysis ( Fig. 7-65 ).
EVALUATION CRITERIA The fol lowing hould be clearly demon strated: • Medial l y superimposed superior and inferior rami of the pubic bones • early superimpo ed lateral two third of the pubic and i chial bones • Symmetric pubes and i chia • Pubic and i chial bones centered to the radiograph • H i p joints • Anterior pelvic bones Fig. 7-64 Superoinferior axial pelvic bones: Lllienfeld method.
NOTE: The " Inlet" can also be demon trated with the patient upine and the CR angled 40 degrees caudad.
Acetabulum
Femoral head
Superior pubic ramus Ischial tuberosity Ischial ramus Pubic symphysis
Inferior pubic ramus
386
Fig. 7-65 Superoinferlor axial pelvic bones: Llilenfeid method.
Anterior Pelvic Bones
PA AXIAL "INLET" PROJECTION STAUN IG METHOD I
Image receptor: 8 x 1 0 i nch ( 1 8 x 24 c m ) crosswise Position of patient •
Place the patient in the prone position.
Position of part •
•
•
•
•
Center the midsagittal plane of the body to the midl ine of the radiographic table. Adjust the body so that the pelvis is not rotated. With the IR in the B ucky tray, adj ust its position so that the midpoint of the I R w i l l coincide with the central ray ( Fig. 7-66).
Central ray •
EVALUATION CRITERIA
Directed 35 degrees cephalad exiting the pubic symphysis on the midsagittal plane anteriorly at the level of the greater trochanters
Structures shown The resulting i mage shows a PA axial pro jection of the pubic and ischial bones and the pubic ymphy is. The appearance of this radiograph w i l l be nearly identical to the superoinferior axial projection dis cussed previously.
The fol lowing should be clearly demon strated : • Medially superimposed superior and inferior rami of the pubic bones • Nearly superi mposed lateral two thirds of the pubic and ischial bones • Symmetric pubes and ischia • Pubic and ischial bones centered to the radiograph • Hip joints
Shield gonads. Respiration: Suspend.
'Staunig K: Die axiale Aufnahme der Regio pubica. For/sellr Roel//gel/s/r 27:5 1 4. 1 9 1 9- 1 92 1 .
Fig. 7-66 PA axial anterior pelvic bones: Staunig method.
387
I lium
AP AND PA OBLIQUE PROJECTIONS
• Elevate the unaffected side approxi mately 40 degrees to place the broad surface of the wing of the affected ilium parallel with the plane of the IR. Support the elevated shoulder, hip, and knee on sandbags. • Adjust the position of the uppermost l i mb to place the ASISs in the same transverse plane (Fig. 7-67) . Center the I R a t the level o f the ASIS. • Shield gonads. Respiration: Suspend.
Image receptor: 24 x 30 cm length wi e
•
RPO and LPO positions Position of patient •
Place the patient in the supine position.
RAO and LAO positions Position of patient •
Position of part •
•
•
Position of part Center the sagittal plane passing through the hip joint of the affected side to the midline of the grid.
Place the patient in the prone position.
•
•
Center the sagittal plane pas ing through the hip joint of the affected side to the midline of the grid. Elevate the unaffected side about 40 de grees to place the affected ilium per pendicular to the plane of the I R . Have the patient rest o n the forearm and flexed knee of the elevated side. Adj ust the position of the uppermo t thigh to place the i l iac cre ts in the same horizontal plane. Center the IR at the level of the ASIS (Fig. 7-6 8 ) .
• ShieLd gonads. • Respiration: Suspend.
Central ray • Perpendicular to the midpoint of the I R
Structures shown The AP oblique image hows an unob structed projection of the ala and sciatic notches and a profile image of the acetab ulum (Fig. 7-69). The PA oblique image hows the i lium i n profile and the femoral head within the acetabulum (Fig. 7-70).
EVALUATION CRITERIA Fig. 7-67 AP oblique ilium, RPO.
, 388
..
�---
.
-
Fig. 7-68 PA oblique ilium, LAO.
The following should be clearly demon strated: • Entire i l ium • H ip joint, proximal femur, and sacroil iac joint AP oblique projection • B road urface of the il iac wing without rotation PA oblique projection • Ilium in profi le
I lium
Ala of Ilium
Greater sciatic notch Acetabulum
Femoral head Lesser sciatic notch
Fig. 7-69 AP oblique ilium, RPO.
Sacrum ilium
Sacroiliac joint
Acetabulum
Femoral head
Fig. 7-70 PA oblique ilium, LAO. 389
8
OUTLINE
§!GeI.- . -
-
SUM MARY O F PROJ ECTIONS
PROJ ECTIONS,
Page
•
I
I
Essential
Atlanto-occipital articulation
AP oblique
412
Atlanto-occipital articulation
PA
Dens
AP
41 3 414
• •
& M ETHODS
Projection
Anatomy
410
Position
Method
R and L head rotations
FUCHS Open mouth
Atlas and axis
AP
Atlas and dens
PA
41 7
Dens
AP axial oblique
R or L head rotations
418
Atlas and axis
Lateral
R or L
Cervical vertebrae
AP axial
Cervical vertebrae
Lateral
R or L
Cervical vertebrae
Lateral
R or L hyperflexlon or hyperextension
Cervical intervertebral foramina
AP axial oblique
RPO and LPO
Cervical intervertebral foramina
AP oblique
Hyperflexion and hyperextension
Cervical intervertebral foramina
PA axial oblique
RAO and LAO
430
Cervical vertebrae
AP
432
Cervical and upper thoracic vertebrae: vertebral arch (pillars)
AP axial
434
Cervical and upper thoracic vertebrae: vertebral arch (pillars)
AP axial oblique
R and L head rotations
435
Cervical and upper thoracic vertebrae: vertebral arch (pillars)
PA axial oblique
R and L head rotations
Cervlcothoraclc region
Lateral
R or L upright
TWINING
Cervicothoraclc region
Lateral
R or L recumbent
PAWLOW, MODIFIED PAWLOW
440
Thoracic vertebrae
AP
442
Thoracic vertebrae
Lateral
416
420 422 424 426
• • • •
427 428
•
POSITIONS
436 438
•
• •
JUDD KASABACH
GRANDY
OTTONELLO
R or L
Icons In the Essential column indicate projections that are frequently performed in the United States and Canada. Students should be competent in these projections.
PROJ ECTIONS,
448 452 454 456 458
• • •
460 462
•
462 i
l l I
II
!
I �
464 466
468 470 470 472 472 474
• • • • •
POSITIONS,
& M ETHODS
Lumbar-lumbosacral vertebrae
PA
Lumbar-lumbosacral
Lateral
R or L recumbent or upri ht
L5-S1 lumbosacral junction
Lateral
R or L
Zygapophyseal joints
AP obllque
RPO and LPO
Zygapophyseal joints
PA oblique
RAO and LAO
Intervertebral foramen: fifth-lumbar
PA axial oblique
RAO and LAO
Lumbosacral junction and sacroiliac Joints
AP axial
Lumbosacral junction and sacroiliac joints
PA axial
Sacroiliac joints
AP oblique
RPO and LPO
Sacroiliac joints
PA oblique
RAO and LAO
Pubic symphisis
PA
Sacrum and coccyx
AP axial (sacrum)
Sacrum and coccyx
AP axial (coccyx)
Sacrum and coccyx
Lateral (sacrum)
R or L
Sacrum and coccyx
Lateral (coccyx)
R or L
Sacral vertebral canal and sacroiliac joints
Axial
CHAMBERLAIN
NO LKE R and L bending
Lumbar Intervertebral disks
PA
Thoracolumbar spine: scoliosis
PA lateral
Thoracolumbar spine:
PA lateral
482
Lumbar spine: spinal fusion
AP
R and L bending
484
Lumbar spine: spinal fusion
Lateral
R or L hyperftexlon and hyperextension
476 478
•
480
•
KovAcs
WEIGHT- BEARING
FERGUSON
�I:��
ANATOMY
Vertebral Column The vertebral colulI1ll. o r spine. forms the central axis of the skeleton and is centered in the midsagittal plane of the posterior part of the trunk. The vertebral column has many function : it encloses and pro tects the spinal cord ; it acts as a support for the trunk; it supports the skul l superi orly ; and it provide for attachment for the deep muscles of the back and the rib lat erally. The upper l i mbs are supported in direct ly via the ribs, which articulate with the sternum. The sternum in turn articu lates with the houlder girdle. The verte bral column articulates with each hipbone at the acroil iac joints. This articu lation supports the vertebral column and trans mits the weight of the trunk through the hip joint and to the lower l imb . The vertebral column is composed of small segments of bone called vertebrae. Disks of fibrocartilage are interposed be tween the vertebrae and act as cu hions. The vertebral column is held together by l igaments, and it is joi nted and curved so that it has considerable flexibil ity and re i l ience.
The 24 vertebral egments in the upper three regions remain distinct throughout life and are termed the true or movable veltebrae. The pel v ic egments in the two lower regions are cal led false or fixed ver tebrae because of the change they undergo in adults. The acral segment u ual l y fu e into one bone called the sacrum, and the coccygeal egment , referred to as the coccyx. al 0 fu e into one bone.
In early life the vertebral column u ually consists of 33 small, irregularly shaped bones. These bones are divided i nto five groups and named according to the region they occupy ( Fig. 8- 1 ). The most uperior even vertebrae occupy the region of the neck and are termed cervical vertebrae. The succeeding 1 2 bones lie in the dorsal, or posterior, portion of the thorax and are called the thoracic vertebrae. The five ver tebrae occupying the region of the loin are termed lumbar vertebrae. The next five vertebrae, located in the pelvic region, are termed sacral vertebrae. The termjnal ver tebrae, also in the pelvic region, vary from three to five in number in the adult and are called the coccygeal vertebrae.
A
Cervical
{
B
Cervical curve (convex anteriorly)
{
Lordotic curve
Thoracic
Thoracic curve (concave anteriorly)
Kyphotic curve
Lumbar
Lumbar curve (convex anteriorly)
Lordotic curve
Pelvic curve (concave anteriorly)
Kyphotic curve
Sacrum
Coccyx
Fig. 8- 1 A, Anterior aspect of vertebral column. B, Lateral aspect of vertebral column. showing regions and curvatures.
394
Vertebral Curvature Viewed from the side, the vertebral col umn ha four curves that arch anteriorly and po teriorly from the midcoronal plane of the body. The cervical, thoracic, lum bar, and pelvic curves are named for the regions they occupy. In this text the vertebral curve are di cussed in reference to the anatomic posi tion and are referred to as " convex anteri orly" or "concave anteriorly." Because physician and surgeons eval uate the pine from the po terior a pect of the body, convex and concave terminology can be the exact opposite . For example, when viewed posteriorly, the normal l um bar curve can correctly be referred to as "concave posteriorly." Whether the curve i de cribed as "convex anteriorly" or " concave po teriorly," the curvature of the patient's pine is the ame. The cervical and lumbar curves, which are convex an teriorly, are called lordotic curves. The thoracic and pel vic curve are concave an teriorly and are called kyphotic curves (see Fig. 8- 1 , 8). The cervical and tho racic curve merge smoothly.
A
The lumbar and pelvic curves join at an obtuse angle termed the lumbosacral an gie. The acuity of the angle in the junction of these curves varies in different patients. The thoracic and pelvic curves are called primary curves because they are present at birth. The cervical and lumbar curves are called secolldary or compensatory curves becau e they develop after birth. The cervi cal curve, which is the least pronounced of the curves, develops when the child begins to hold the head up at about 3 or 4 months of age and begins to it alone at about 8 or 9 months of age. The lumbar curve devel ops when the child begin to walk at about I to I � years of age. The lumbar and pelvic curves are more pronounced in fe males, who therefore have a more acute an gie at the lumbosacral junction.
Any abnormal increase in the anterior concavity (or posterior convexity) of the thoracic curve i termed kyphosis (Fig, 8-2, 8). Any abnormal increa e in the anterior convexity (or po terior concavity) of the lumbar or cervical curve is termed lordosis, In frontal view the vertebral column varies i n width in several region ( ee Fig. 8- 1 ), Generally the width of the spine gradual ly increa es from the econd cervi cal vertebra to the superior part of the sacrum and then decreases sharply. A slight lateral curvature is sometimes pres ent in the upper thoracic region, The curve is to the right in right-handed persons and to the left in left-handed persons, For this reason, lateral curvature of the vertebral column is bel ieved to be the result of mus cle action and to be influenced by occupa tion. An abnormal lateral curvature of the spine is called scoliosis. Thi condition also causes the vertebrae to rotate toward the concavity, The vertebral column then develops a second or com pen atory curve in the oppo ite direction to keep the head centered over the feet ( Fig. 8-2, A ).
B
Scoliosis
Anterior view
lateral view
Fig. 8-2 A, Scoliosis, lateral curvature of the spine, B, Kyphosis, increased convexity of the thoracic spine. Lordosis, increased concavity of the lumbar spine,
395
Typical Vertebra A typical vertebra is composed of two main
parts-an anterior mass of bone called the body and a po terior ringlike portion called the vertebral arch (Figs. 8-3 and 8-4). The vel1ebral body and arch enclo e a pace called the vel1ebral foramen. In the articu lated column the vertebral foramina form the vertebral canal. The body of the vertebra is approxi mately cylindric in shape and i composed largely of cancellous bony tissue covered by a layer of compact ti ue. From the u perior a pect the posterior urface is flat tened, and from the lateral aspect the an terior and lateral surfaces are concave. The superior and inferior urface of the bodie are flattened and covered by a thin plate of articular cartilage. In the al1iculated spine the vertebral bodies are separated by intervertebral disks. These di k account for approxi mately one fourth of the length of the ver tebral col umn. Each disk ha a central mass of soft, pulpy, semigelatinous mate rial called the nue/eus pulposus, which is surrounded by an outer fibrocartilaginous disk called the annulus fibrosus. It is fairly common for the pulpy nucleus to rupture or protrude into the vertebral canal, thereby i mpinging on a pinal nerve. Thi condition i called herniated nucleus pul posus (HNP), or more commonly slipped disk. H N P most often occurs in the lumbar region as a result of improper body me chanic , and it can cau e considerable dis comfort and pain.
The vertebral arch (see Figs. 8-3 and 8-4) is formed by two pedicles and two laminae that supp0l1 four articular processes, two tran ver e proces es, and one spinous pro ces . The pedicles are hort, thick proce ses that project posteriorly, one from each side, from the superior and lateral parts of the posterior surface of the vertebral body. The superior and inferior surfaces of the pecti cJes, or root , are concave. These concavi ties are called vertebral notches. By articu lation with the vertebrae above and below, the notche form intervertebral foramilla for the tran mission of spinal nerves and blood vessels. The broad, flat laminae are ctirected po teriorly and medially from the pedicJes. The transverse processes project later ally and slightly posteriorly from the junc tion of the pedicJes and laminae. The spin ous process project posteriorly and i nferiorly from the junction of the laminae in the posterior midline. A congenital de fect of the vertebral column in which the lan1inae fail to unite posteriorly at the mid l ine is called spina bifida. In erious case of spina bifida the spinal cord may pro trude from the affected individual's body.
Spinous process Facet ------��.. Pedicle
Body
Vertebral foramen
Fig. 8-3 Superior aspect of a thoracic vertebra, showing struc tures common to all vertebral regions.
396
Four articular processes, two uperior and two inferior, ari e from the junction of the pedic\es and lami nae to articulate with the vertebrae above and below (see Fig. 8-4). The articulating surface of the four articular processes are covered with fibrocartilage and are called facets. In a typical vertebra, each superior articular process has an articular facet on it po te rior surface, and each illferior articular process has an articular facet on the ante rior surface . The planes of the facets vary in direction in the different regions of the vertebral column and often vary within the same vertebra. The articulations be tween the articular proces es of the verte bral arches are referred to as zygapophy seal joints. Some texts refer to the e joints a interarticular facet joints. The movable vertebrae, with the excep tion of the first and econd cervical verte brae, are similar in general tructure. However, each group ha certain di tin guishing characteristic that must be con sidered in radiography of the vertebral column.
Superior articular process Transverse process Spinous process
process
Fig. 8-4 Lateral aspect of a thoracic vertebra, showing structures
common to all vertebral regions.
Cervical Vertebrae The first two cervical vertebrae are atypi cal in that they are structurally modified to join the kull. The eventh vertebra is atypical also and sl ightly modified to join the thoracic spine. Atypical and typical vertebrae are described i n the fol lowing sections.
ATLAS The atlas, the first cervical vertebra, is a ringl ike structure with no body and a very hort pinous proce ( Fig. 8-5 ). The atlas consi ts of an anterior arch, a posterior arch, two lateral masses, and two trans verse processes. The anterior and poste rior arches extend between the lateral ma ses. The ring formed by the arches is divided i nto anterior and posterior por tions by a l igament called the transverse atlantal ligament. The anterior portion of the ring receives the dens (odontoid proce s ) of the axis, and the posterior por tion transmits the proximal spinal cord. The transver e proces e of the atlas are longer than those of the other cervical vertebrae, and they project laterall y and sl ightly inferiorly from the lateral ma ses. Each lateral mass bears a superior and an inferior articular process. The superior processes l ie in a horizontal plane, are large and deeply concave, and are shaped to receive the condyles of the occipital bone of the cranium.
AXIS
SEVENTH VERTEBRA
The axis, the second cervical vertebra (Figs. 8-6 and 8-7), has a strong conical process arising from the upper urface of its body. This process, called the dens or odontoid process, is received i nto the an terior portion of the atlantal ring to act as the pivot or body for the atlas. At each side of the dens on the superior surface of the vertebral body are the superior articu lar processes, which are adapted to join with the inferior articular processes of the atlas. These joints, which differ i n posi tion and direction from the other cervical zygapophyseal joints, are clearly v isual ized i n an anteroposterior ( A P) projection if the patient is properly positioned. The inferior articular processes of the axis have the same direction as those of the succeeding cervical vertebrae. The lami nae of the axis are broad and thick. The spinous process is horizontal in position.
The seventh cervical vertebra, termed the vertebra prominen , has a long, prominent spinous process that project almo t hori zontal l y to the posterior. The pinous proces of thi vertebra is easily palpable at the posterior base of the neck. It is con venient to use this process as a guide in lo cal izing other vertebrae.
Dens (odontoid process)
Superior articular
Inferior articular process
Transverse process
Facet Fig. 8-6 Anterior aspect of axis (C2).
Dens (odontOid process) ----",.�
Transverse foramen (for vertebral artery and vein)
Superior articular process and facet Lamina
Anterior arch
Superior articular process and facet
Transverse atlantal ligament
Fig. 8-5 Superior aspect of atlas (C l ).
Spinous process
process
Facet
Body Transverse foramen
Fig. 8-7 Lateral aspect of axis (C2).
397
TYPICAL CERVICAL VERTEBRA The typical cervical vertebrae (C3-C6) have a smal l, transversely located, oblong body with sl ightly elongated anteroinferior border (Figs. 8-8 and 8-9) . The result i anteroposterior overlapping of the bodies in the articulated column. The transverse processes of the typical cervical vertebra arise partly from the side of the body and part l y from the vertebral arch. The e processes are short and wide, are perfo rated by the transverse foramina for the transmission of the vertebral artery and vein, and present a deep concavity on their upper surfaces for the pas age of the spinal nerves. All cervical vertebrae contain three foramina: the right and left transverse foramina and the ver1ebral foramen.
The pedicles of the typical cervical ver tebra project laterally and po teriorly from the body, and their superior and in ferior vertebral notches are nearly equal in depth. The lami nae are narrow and thin. The spinous processes are short, have double pointed (bifid) tips, and are di rected posteriorly and slightly inferiorly. Their palpable tips l ie at the level of the inter pace below the body of the vertebra from which they arise.
The superior and inferior articu lar proce es are located posterior to the trans verse processes at the point where the pedi cles and laminae unite. Together the processes form short, thick columns of bone called articular pillars. The fibrocar ti laginous articulating surfaces of the ar ticular pil lars contai n facet . The zyga pophy eal facet joints of the econd through seventh cervical vertebrae lie at right angles to the midsagittal plane and are clearly demon trated in a lateral pro jection ( Fig. 8- 1 0, A ).
Spinous process with bifid tips
Vertebrol .. f'i__ foramen -...tfl
Superior articular process and facet
Pedicle
A
Transverse foramen (for artery and vein)
Body
Fig. 8-8 Superior aspect of typical cervical vertebra.
Superior artlculor process
Articular pillar
Lamina
Body
Spinous
Inferior articular process
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