Netter's Atlas of Human Neuroscience

EFACE "'"' S

":"i.las of Human Neuroscience combines

f'C'I)e~~ and beauty of Dr. Frank N etter's illu5tra­

;:)a)icting both regio nal and syste mic neuro­ 'r '.\ ilh updated info rm ation and beautiful new

n:o-ts to reflect our growing understanding of --e-g.ions and systems of the brain, the spinal ~.'j(j the periphery. This Atlas also includes new ~ns through the spinal cord and the brain ~ \'. e ll as coronal and horizontal sections cor­ "::O.,., ....-ith ,'vIRls. We have chosen to let the iIIustra­ :J'1J'\ ide the focal point for learning.. rather than

org. detailed written explanations th at cou ld - ..,:e fl 0 1 these LMNs by bra in stem and cortica l )per motor neuro ns (UMNs), and th e co ordin a­ 110 and modulation of UMN regulati on by the ~ebellu m and the basa l gangli a, and (3) pregan­ onie autonomic connections to peripheral tar­ ts through autonom ic ganglia, and the central O.IllS irom th e brain stem, the hypothalamus, and ;> limbic str uc tures that regulate and coordinate mautonomi c and neuroendocrine o utflow. A

Kough un derstand ing of these hi erarchies-as

~nted in the in troduction to the PNS-is the

InOation ior the rest of the Atlas.

The section on the PN S next offers a systematic collection of illustrations of roots, plexuses, and peripheral somatic nerves, w hich prov ides a smooth transition between th e central and the periphe ral aspects of neuroscience. The illustra­ tions of the major peripheral nerves are con­ ducive to acquiring a better un derstanding of neuropathies, w hich are so frequently enco untered in medical practice. 'vVe have tried to bring together the basics of periphera l nerve anatomy, fu nction, and cl inical deficits in as simple and suc­ cinct a fash ion as possi ble in the figure legen ds for the periph eral nerves. The section on the PNS next outlin es the o rgani­ Zation and the major d istribution networks of the auto nomic nefVOU5 system . These illustrations are important for many reasons, including understand­ ing auto nomic disorde rs and the effects o f a ho st of pharmacological agen ts that infiu ence th e auto­ nomic nervou s system and its associated adrener­ gic and cholinergi C receptors. In addition, w e are becoming increaSingly aware that maj or life stres­ sors and life style factOfs play an importan t role in the onset,. progressio n, and o utcome of atheroscle­ rosis and cardiovascular disease (including cere­ brovascular disease), cancer, diabetes, chronic pulm onary disease, and even neurodegenerative diseases and that these factors exert their phys io­ logical effect in large part th rough neural o utflow via the autonomic nervous system and v ia hypo­ thalamo-pituitary-neuroendocrine outflow and that they have an impact on cytokines, hormones, infl amm atory mediators, and a va riety of immune responses. The updates to our und erstanding of peripheral autonomic mechan isms include th e depiction of autonomic interactio ns with cells of the immune system and w ith metabo lic cells such as hepa tocytes and fat cells. ..,jj The brain stem is usua lly the " terra incogn ita" o f neuroscience cou rses and can be an exercise in memorization and m inutiae if not pro perly o rga­ nized. This Atlas provides the o rgani zatio n for rather st raightforward understanding of the brain stem, despite its com plexities and intricacies. The brain stem has six major components: (1) sensory nudei and their pathways- includin g secondary senso ry nuclei and pathw ays for incoming sensory information to th e brain stem (tri geminal, auditory, vestibul ar, taste, visual), as w ell as somato sen sory nuclei and chann els, (2) LMNs for the cranial nudei, and descending UMN chan nels that control

•

ClL or

-

->, telencephalon has fou r major func­ ov-ponenls-cerebral cortex, basal ganglia, i"Of"din sys tem, and o lfactory system- we -=c,..~",r . emp hasi ze th e ce reb ral co rtex anatomy .....-eGio ns in th e Regio nal N eurosc ience sec­ - ---... ,~ ~. "

c'

"

, go' ; '

.

/

::>':.~

t •

,

0,

" .

I, ,

I. Serial syna pse

• - t itie synapse

... L

u

~J~

Dendro­ de ndri tic;

'Y"'P" K. Inner plexiform la ye r of retin a i~ '

~

,,~.

r.')l. ~ .

~'a~gli'o n , '"

}~i~~cell ' t'in%%j')r) \

j

,.g9'

"

,._., " ,'/o'"::'e e"di oss

~ En(~psu l atE'd end ln ~ .......... Musck,: spindle

~~f!% · ','l.!.N

FIGURE 1.3: NEURONA L CEll TYPES _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ __ l ocal interneurons and projection neuro ns demon­ strate characteristic size, dendritic arbo rizatio ns, and axonal projections. In the eNS, glial cells (astrocytes, microglia, oligodendroglia) provide suppo rt, protection, and maintenance of neurons. Schwa nn cell s and satellite cells provide these func­ tions in the PNS. TIle primary sensory neurOns (blue) provide sensory transduction of in co ming

6

energy or stimuli into electrical signals that are conveyed into the eNS. The neuronal o utflow from the e NS is motor (red) to skeletal muscle fibers via neuromuscular junctions, o r autonomic preganglionic (red) to autonomic ganglia, w hose neurons inn ervate cardi ac mu scle, smooth mu scle, secretory gland s, metaboli c cells, or cell s of the immu ne system.

The ir Properties Structure

OVERVIEW OF THE NERVOUS SYSTEM

.-

J. Perki'ns M S. MFA

C: DN "....'"

~.

G LIAL CE LL TYPES _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ __

- - ,...- ~id e structural isolatio n of neurons _ -'-.a:pses. and they provide ioni c (K' ) ~=:a>a' trophic support. and suppo rt for __-','-'" ~ ;;naling functions to neurons. c.~ :ro-~ provide myelination o faxons in «roglia are scavenger cells that partici­ ~ X\ tosis. infla mmatory responses, - ~ JD: ¥J0 \\ th fac to r secretio n, and some

.....

immune reactivity in the e NS. Pe rivascular cells participate in similar activiti es at sites near the blo od vessels. Schwann ce ll s provide mye lination, ensheathment, tro ph ic suppo rt, and actions for grow th and repair for peripheral neurons. Activated T lymphocytes can enter and traverse the eNS for immune surveillance for a period of approximately 24 hours.

7

OVERVIEW OF THE NERVO US S) STEM

'\e urons and Their Pro pert:irs:-St ru ct ure

CENTRAL NERVOUS SYSTEM

PERIPH ERA L .' ERVO U S SYSTEM

Sensory neuro n

cell body

Pia m,lter

Oligo­ dendro cyte

~

SchWimn cells associate d w ith myelin sheaths 01 myelinated axons

f--- - - - ­·t-I­

Bouto ns of associati o n neuro ns synapsi ng

with preganglionic aulonomie neuron o f CwainSlem o r spinal cord

Schwa nn cells assoct' of peripher"t neufon,s

::i

or viscp.rai motor,)

""~

(sensory, somatic motor t beins surroutidec:/ by

:"

cytoplasm 01a neurilemmal (Schwarm) . cell ~'.

B. Myelinated 011(00.01 peripheral neuron

(sensory, somatic.motor of Ihetic

0 1 vi5c.ernl motor)

being surrounded by a wrapplng'oi cell memb~eoia

neiJ(ileml)'lal (~wann)

",Jl

c. Mye linated .uon

"1

of eNS neu rons being SUfm~lIldcO by il wrapping of cell

membrane of an oliKodendlOcyte.

;

1 -1 1:

:~

r

Unmyelinated axans

)

of e NS neurons ale leit unprotected.

,

'il

Axon O ligodendrocyte

FIGURE 1.6: DEVELOPME NT OF MYEliNATION AND AXON ENSHEATHMENT _ _ _ __ _ ng

\r\yelination is a cooperative interaction between the neuro n and its myelinating support cell. Unmyelinated peri pheral axons are invested with a 5ingle la yer of Schwann cell cytoplasm. When a peripheral axon of at least 1 ~m in diameter trig­ gers myelination, a Schwan n ce ll wraps many

layers o f ti ghtl y packed cell membrane around a single segment of that axon. The oligodendroglia I cell ex tends several arms of cytoplasm, whi ch then wrap multiple layers of tightly packed membrane around a single segment of each of several axons.

9

OVERVIEW OF THE NERVOUS SYSTEM

Neurons and Their Properties-Structure

Cell body oi an

"

(neurilemmal
'r po". lyn3Q\io.· ~I II depc>1aru • ...., .~

""''' (utrl'lll. .0..... in dire to ~ cb'i.I~ pm"_pl i~ cell. Th.. n',,/'"'' dfIxIbnUlion bo, . .. ~ noOo. oJ;i&o.ull..........~ dtvubnz;olion

fi"", .t"eic,h .... ~1II>o1d

.,

,,!

>
0 mY

Axop lns m

Ex tracellular

Intracellular potentia l +20 mY

po tentiil l - ~

mY

2

InlrM:ellul31 potffili.:!I -7S mV

Intrac e llular

pOlenlial (mY )

Resti ng polen!ial

-70 f---~;-t-'===--~--==

.,I

t

J, ~ tf. c I~ po ten!ial (mVI_5 1 _ _ _ _=~===~------ : ~. -.;::

Exlrace llular

0

----,\1') I

' - 1,OrnsoPc - '

,e

FIGU RE 1.13: PROPAGATION OF THE ACTION POTENTIAL _ _ _ _ _ _ _ _ _ _ _ __ W hen an AP is initi ated at a specific site o n the axona l membra ne (usually th e initial segm ent), the inward flow o f Na-l- alt ers the extracellular ion environment, causing a local flow of charge from adjacent regio ns of the axon. This induces a depo­ larized state in th e adjace nt node of Ra nvier or patch of axo nal membrane, bringing th at regio n to

thresho ld and resu lting in the reinitiation of th e AP. The presence of myelination alo ng axo nal seg­ ments resu lts in the reinitiatio n of the AP at the nex t node, thus hastening the velocity of conduc­ tio n of the AP. The resultant appearance of the AP skipping from node to node dow n the axo n is call ed sa ltatory cond ucti on.

17

OVERVIEW OF THE NERVOUS SYSTEM

A. Myelinated fibers

+ ;./:.J.}

L

, ..

Neurons and Their Properties-Electri ca l Properties

.. -

Site where ac tion potential is reinitiated

/

+

Node

B. Unmyelinated fibers

/l

C. Classification of nerve fibers by si;re and conduction velocity

12°i 1 10

1

100

~

M yejin.lledfibers/4 '

~ Alpha motor neurons to extlaiusal stria ted (somatic ) m usc le fibe rs (malOf end plates)

90

80

Gamma mOtor neurons to intrafusal l"ibers o f spindles

\

in striated muscle

~~ ° IIliN 1\'::.'::

Group I (Ao: fib ers) Ja fro m primary muscle

spindle endings: p roprioceptio n; Ib fro m Goigi tendon o rgans: p roprioception

70

Co nduction velocity 60 (meterslsec) 50

G roup 11 (AP libers) flOm secondary endings of muscle spindles: proprioception; from specialized

U,'U'PIOIS in skin and dee p ti ssues: touch, pressure

40

30

20 10

Group III (AS iibeTs) irom iree a nd from some sp ecialiled endings in mus$ory nn .

~~p " 11liN .. : ::,': \

FIGURE 1.18: FORAMINA IN THE BASE OF THE ADULT SKULL _ _ _ _ _ _ _ _ _ __ This illustration of the foramina in the ba se of the skull lists the major nerves and blood vesse ls that course through each opening. Press ure,

22

traction, or masses can damage structures travers­

ing in these tightly co nfined spaces.

I

-

ers-

OVERVIEW OF THE NERVOUS SYSTEM

---------------------------------------------

Brain Brain

i I margin of cerebrum

Frontal (Fl . irontop;llletal (FPJ and temporJI (T) opercula

'el' C~

!)

.,.,

'dJ.....

cor 28

Brain

OVERVIEW OF THE NERVOUS SYSTEM

Brain

Genu 01 corpus c.Jllosum

/;ep',"", pelludrlum Head o f caudale nucll'US

Anterior li mb _ Genu Posterior limb II

} 'nlernCl , capsu le

co rtex

I ( p

Pineal gland 1.1Ieral vemride CIUS 0 ; iornix

Hippocamp us

and fimbrr a

Spleniu m o f corpus callosum

\P,,,,,,.,ioc loccipital)

horn of faleral

ventricle

Cauda te { nucleus

Head _

_ -, 't .~- - -. ----- - --

lev~ ls of {A - - ­ ~ect10nS

------ ---- ­ B --- ------ ---- -

-\+ - -- -------

lentiform nudeus to p u tamen ) {globus p.-tllidus med"1'nte, ;o, n ucleus oi thal amus

i~'

Intcrv!3 nlrlculal foramen

Slri,l lermina lis A.nte:IOr commi~",u l e

Stria medu lJ.lris

Cingulate Rvrus

Imgli~eum,- ~ Corpu~ ctum p elludrlum

e>1l11c1e

o-.;.aple,us

/,Cnl'cm,,, of forn ix

/ ,,,to', , ,, tubercle

_"" , _etJ(al v. ,/

/

" " 0 terminalis

II" to"h" I"" " ad hesion medu ll,u is

lal~ral

geniculate body

Medial geniculate body

Brachium of inferior coliiculu s

-",-~ ,

Superior co llicu lus

Inferior colliculus

r, "Heral

.:..It:a.-ine sulcus - _/ ~;.....el

_

~~L

~MICANATOMY

________________________________________

.....:::-::>- 6 \. 'ew ed from above. The entire - brain, just late ral to the thalamus, Ed. the head of the ca uda te IIf"er,

secti oned, the corpus callosum

oorsaJ to the th alamus have been :he th ird ventricl e has been opened

sl.u ia ce. The pin eal gland is present ~.;~•. tlS"t

caudal to th e third ven tricl e; it "",...:""i..-1. a horm o ne that he lps regulate ~ . sleep, and immune responses.

The superior and in ferio r colliculi are shown, depicting the do rsal surface of the midbrain. O n the left, the tempo ral horn of the lateral ventricle, with the hippocampal formation, has been exposed to show the relationship of these struc­ tures to th e thalam us. The terminal vein and the choroid plexus acco mpany the stria term inali s alon g th e lateral margin of the thalamu s. The stria med ull aris runs alo ng the medial surfa ce of the dorsal tha lam Ll s.

33

OVERVIEW OF THE NERVOUS SYSTEM

Brain

3.d Internal medull':Hy

la mina

,

J ld ventricle

'-- Reticular nucleus o f rhalJmus

M idline (medim'--;

cerebellar l)edun cle

Superior me,,",,II,,yv',,.I"

Medi al e mo'o" ,r e -,

:-;

,,

Rhomhoid fossa of 4 th veonlricle - - - - ..,

f"",:~::;:::::;J~

ti

Cuneate

Gracile

Dorsal roots of I 5t spina l n. ((1 1

~

peduncle [II n.

I II

peduncle

°

~=~I~GIosS()Phary n 8eal (IX) and vagus (X l nn. HWoglossaltrigo ne I trigone AccesslXY (Xl) n.

tract

Anterior view

Optic

ill

1

Temp oral lone

Tuber

oop:,~,c:::~==::=t~~

Cerebral pi

Posterior pE'floralcd

substance

I

n.

~~1::J4=;::'~"'" UV ) n. --=~~~::,~~' {Vt) :~: o.n.

In

:....

I (VII) n.

Lateral genlculale Basilar

I

I.

,m,,,,_­

Middle cerebellar

(Villi

___

ped uncle - - - - Ii, VenTral roots oi lst spina l n . (C1 I

-

"cen-

Outer,

lala­

Ons

- - - -'k

FIGU RE 1. 3 ~ : BRAIN STEM SURFACE ANATOMY: PO STE RO LATERAL AND ANTERIOR VIEWS_ Top) Th e entire tel encephalo n, most of th e dien­ cep halo n, and th e cerebe llum are rem oved to show the dorsa l su rface of the b rain stem. Th e 3 cerebel­ lar peduncles (superior, middle, inferio r) are sec­ tioned, and the cerebellum is removed. The do rsal roo ts and the cranial nerves provide input to the sp in al cord and provid e input and output to the brain stem, respectively. The fourth nerve (troch lear) is the on ly cranial nerve to exit dorsa lly from the brain stem . The tubercles and trigones on the floor

of the fo urth ventricle are named for nu clei just benea th them. (Bottom) The left temporal lobe is di ssected to show the anterior (ventral ) surface of the brain stem. Th e cerebral ped uncles, caudal extensions o f the posterior limb o f the internal cap­ sule, ca rry corticospinal and corticobulbar fibers from the internal capsu le to the spinal cord and the brain stem, respectively. The decussation of the pyramids marks the bo undary between the ca udal medulla an d the cervica l sp inal cord.

35

OVERVIEW OF THE NERVOUS SYSTEM

Brain Stem and Cerebellum

Superior surface

~ Q u .,,: " .

"" "u

1"

L1cuna

";: ; ••-/;~- :.. ....,"' •. • ,..

. . . . . . ~. :::::::.==____~____ __ r.

".-~. p0campU5

---

HillPOc.:J mpus

lenous

one­ he

fal blood, lent II pres­

es.

'er the

is blood

ecfs

Ira l

sed

lation

-'-~ Piilmilt e r

- - : --

-

De ... tate g)'(U5 Suhirulum P.J ra hippo campal (.Ortex

'(,,;'=:,----:,.,;- - - fl1 10rhlll JI CO"ex

FfGURE 1.42 : VENTRICULAR ANATOMY _ _ _ _ __ _ _ _ _ _ _ _ _ _ _ _ __ The lateral ventricl es are (-shaped, reflectin g their dssociation w ith the develop in g telencep halon as it sweeps upward, back, and then dow n and forward dS the temporal lo be. The positio n of the lateral ventricles in relatio n to the head and body of the caudate nucleus is an important radio logical land­ mark in a va ri ety of co nditions (hydrocephalus, cau­ date atroph y in Huntington's disease, and shifting of the midlin e w ith a tumor). (SF fl ow s through the foram en of M o nro into the narrow third ventricle,

then in to th e ce reb ral aquedu ct and th e fourth ventricl e. Blockage of tlow in the aqu edu ct can pre­ cipitate int ernal hydrocephalu s, w il'h swelling of the ventricles above. The escape sites for (SF to flow into the subarachnoid (SA) space cisterns are the medial foramen o f M agendie and the la teral foramina o f Luschka, w here blocka ge of (S F tlow can occur. Th e choroid pl exu s, extending into the ventricl es, prod uces the CS F.

43

OVERVIEW OF THE NERVOUS SYSTEM ~Hi

PO;;\f . io . "iew

Ventricles and the Cerebrospinal Spinal Fluid

venlnclC'

Habenula. trigon!'

PUI\-jO,l'

l aterJI }

Geniculate bodies

....Iedial

Pine ,l l gl.lnd '

-

Supe rior colliculus Media n sulru s Tro ch lear (IV) nervl!---.. Superior medullary velum

Cere~lJar , ,o'd I~oondcs {"p

~-
ll tfll!one l

"-<J..:ifcorpus callosum

Prece nuallprerola ndic l, cerllral (rola nd ie)

and parielal b,"""h,, -~ lateral cerehrallsylvi an)

Inte rnal

11,,," ,,/1

c~ p,ul£

(anlerior li mb)

' -.;,.- 5epl\ lm pellucidum :>:-~"...- ROSTl um of corp us callosum

Temperal b ,."d' .,,-~

'"'.
;

-

FIGURE 1.52: COLOR ILLUSTRATION OF TERRITORIES OF THE CEREBRAL ARTERIES _ _ __ Th e specifi c mid lin e and lateral territo ri es of di stri­ bution of th e ACA, M CA, and PCA illustrate the exclu sive zo nes supplied by th ese major arteries

and make particularl y d ear the wa tershed zones at the junctions of th e majo r cerebral arteries.

.

53

OVERVIEW OF THE NERVOUS SYSTEM

Vasculature

Femoro cel"('b ral Angiography L>'.... I ... oj« "

o~

Vase!

-

f.......t ~~

~".:..IJlo...l. C.ilr> "", ,, , ~..,. I '

,;",1 A~:",c
(",-cb r. ,I"

foIGa "",' :'

I

/

D""'I> middle cereb, ~I ,. In/. lhaL'''·'OS1r h)lf' ""_

B;o,.a IY.lui ,,'_""," In!. hom o f l" lcd

(,-,r~he,,,.,,,,',,et,oall anastomosis _A"v,~ .eb..'

anastomosis

Section through thoracic spine

~_ ~~;~:.:~~::~~,:::: ~Q

I branchesa, from pial plexus

Central branches to right side of ,p;n" w,d -----A~r:5:

_,Cen'"

branches to left side of cord poste rior spinal a.

Anterior radicular ,,-- - - -

Pial arterial

_-Zo" supplied by pen etrating branches from pial plexus

p' e"'----.•,"1>.~'

.........:: ~~.~~'b..":~",",N~ ;-~

~

Sensory ne\Jron o f

dorsal spinal ganglion

Dorsal spinal ga nglion Spin al cord Sympa thetic tronk gan glion

~.>.< ___-;r ':'.,: : ~"

Visceral mOtOr neuron 01 sympa thetic ga nglion

,,~.;'·r.~~; Cortical p rimordium 01 suprarenal gland

4th week

Dorsal mesen tery Germinal epithelium

Chromaffin ce ll, suprarena l

or future gonad

medulla ce ll

Sero sal li nin g (peritoneum) 01 abdominal celom (peritoneal cavity)

Get

61hweek

-

and

,

Ja)

FIGURE 1.69: NEU RALTUBE DEVELOPMENT AND NEURAL CREST FORMATION _ _ _ _ __ Th e dorsal and ventral halves of the neural tube are separated by the sulcus limitans, an externa l protru­ sion from the ce ntral canal that demarcates the alar plate from the basal plate. This important landmark persists at some sites in the adult ventricu lar sys­ tem , The alar plate is the source of generation of many neurons w ith sensory function . The basal plate is the source o f generation of many neu ro ns

with motor or auto nomic function in the spinal cord and the brain stem. The neural crest cells at the edge of the neural fo lds unite to becom e a dorsal crest, th e neural crest above the neural tube. The neural tube and the neural crest separate from the originating ectoderm. The neural crest gives rise to many cell types in the periphery.

69

OVERVIEW OF THE NERVOUS SYSTEM

Developmental Neuroscience

mater

~

Ce ntral ca nal

zone

Ma rginal lonp (w hi le maile r)

(gray m (l ll e rj

B. Spinal cord a t J months Exlern al limiting

Pial

membrane

cell

\

Migra ti ng neu roblasts

_ _ rom~iiinc d

oi .>d,e ... 1mo:tlull~

~ ria mote, cell

late r

eculM

Iver

FIGURE 1.71: NEURAL TUBE AND NEURAL CREST DERIVATIVES _ _ _ _ __ __ _ __ Neural tube ependymal cells give ri se to neura­

blasts from which the ne urons of the eNS are

; pres.

derived. They also give rise to the glioblasts from

n the zone,

which the mature ependymal cells, astrocytes,

le ntal

,f the

and oligodendrogl ia are derived. Microglia, the "scavenger" cell s o f the eNS, are derived mainly fro m mesodermal precu rsors. Cells of glia l origin are the predominant ce lls that give rise to e NS tumors. Th e neural crest cells give rise to many

sensory neurons, postgan gli onic auto nomic neurons (sympathetic and parasympathetic), adrenal medullary chromaffin cells, pial and arach­ noid cells, Schwann cells (the supporting cells of the PNS), and other specialized cell types. Neural crest cells can be damaged selective ly in some disorders (e.g., familial dysautonomia) and also can give rise to specific tumo r ce ll types, such as pheochromocytomas.

peripheral neural structures, including primary 71

OVERVIEW OF THE NERVOUS SYSTEM

Developmental Neuroscience

•

Central nervous system at 28 days

Midbrain (mesencephalon)

Forebrain

Hindbrain (rhombencephalon)

{~___"

Optic vesi cle

Cervical flexure

E

E

I·

Spinal cord

'" M

/FO"b"" Forebrain (prosencephalon) ~

~--

Alar (rooO plate

..... Midbrain (mesencephalon)

Optic vesicle

~"" .....__Sulcus limitans

Hindbrain (rhombencephalon)

Opening of right Oplic vesicle

_

,

Basal plate / ' Spinal cord

~ 8asal plate

• I--- -­ Hindbrain

~ Sulcus limitans



:n:

.•

C"1

.... .:::-

72

-l

;cience

-

OVERVIEW OF THE NERVOUS SYSTEM

evelopmental Neuroscience

Cranial n. VII (Facia l) (sensory and

Saginill section Metencephalon ~ 'h, Ice re bellum, pons)

Hindbrain . VIII

Cranial n. VI (abducens) 'm'''o,, \

Thin root of myelencephalon ('!',"'«dUI, oblong,na)

(se nsory)

(raniill n. 'V~J',~~:~,:~" (sensory 0'11

Sulcus 'ti"

n. IX

Cran ia l n. IV (trochle;)r) 'm,,,oO'-

mOLOO

"it,""

MesencePhalOn \ Cerebral aqueduct

Cranial n. X

,Midb rain .i.

"w,"',

•

(se nory a nd motor )

Cranial n.11! (oculomotor) (moto r) - - - -

3rd ventricle Opening of right telen­ cephalic vesicle

(myelencephalon)

Coccygeal n. (sensory and motor)

Opening of right optic stalk

" (,m',,, termina li s frontal section (venl ralto sulcus lirnitans) Lamina ventricle terminalis / ' Telencephalic vesicle

//_ (,,,,,,t' verllricle

1st cervica l n. (sensory " " mo;tm)-1

15l sacral 11 . (sensory and

mo,",)' ­ -'." ,

1st lumbar n. (senSO ry

1st thoracic n. (Sensory

"d ~o'M"

"d moton-'

I aqueduct _ _ _ _ B,__,I plale

Central Nervous System: Crania l and Spina l Nerves at 36 Days

.--.J

1

(cerebellum, pons) - - ­ "h ventricle

Sensory neurons and gan glia from neura l crest

- - - Myelencephalon (medull a oblongatiJ) In sagittal and fron\JI sections: ~ Alar (roof) plate

t¥%:.& Basal plale

ventricle ' ­_ _ _ Spinal cord - - - - Central canal

FIGU RE 1.73: EARLY BRAIN DEVElOPMENT: THE 36-DAY-OLD EMBRYO _ _ _ _ _ _ __

- day 36, the prosencepha lo n begins to expand ":JOKIly as the future diencephalon (thalam us and ",alamus) and telencephalon (basal ganglia, ebrain. olfactory system" and cerebral _:~'''~/ in lat eral re('eS5

\l etacoele ..! th ventricle I

0141h

. Mage ndie)

'.--_ - Spinal cord

i I. .1l h vent ricl e

.u lcus

JryJ gyrus

CeOlral ca nal of spinal cord - -

-

­

' - -- - Central canal

dymailining of cavities of brain at 9 months >::: 0-","0.="'= _~-Trigem i nar (VJ n. and

~

..",.

Cortic ospi nal and cortico nuclear fi be r,

:---.~

~'"

.

gang lio n Median ra phe

_ _ _ _ _ _ _ _ _ _ _ _ _ _ Section through pons at level of trigeminal nerves In!. me dull ary ve lum Cho ro id plexus of 4 th ventricle

>m ....,. .t."'(

lei-

'. '

La teral cuneate tn r. cer~bell ar Post. spinoce rebellar trac t Ant spi nocerebellar Irac t ~ . . ;: •.'. Spi nal lemniscus (~i no thalamic tracts) Me di al lon gi tu dina l fascic ulus ~ Medial lem ni scus 4!ro. Section through medulla obI, Cen[ral canal ..........~ Hy poglossal nucleu s~ Post ~pi noc erebetla r lril C! ~~~

Dorsal vagal nud e us Solitary tract nucl e us Spinal tra ct a nd spinal nu cleus of tri ge minal n. Hypogiossoil t n ucleus In f. o livary nucl ei Hypoglossal (XII ,. .at level of inferior o livary nuclei - - - - - - - - - - - - - - ­ Fascic ulu s gracili s Gracile nucleu s Fascic ulus (unealus

Spinotha lam ictraclS ~ :~

An t spinoce rebellar trac t Medi al le mn iscus -

in allract ilnd Spi nal nucl e us of trigemin al n. Int arcuate fibers

- - - - - - - - - - Swion through medulla oblongata Spinal trac t a nd .,pinal nucle us of tri ge minal Po ~t. spinoce rebe ll a r tract

Spinothala mi c trac ts-= Pyramid and ant. cortkos pinal tlbers

Gracile nucleus Fascic ul\p.> cunealus Dors.:l l ho rn Lateroill corticospi na l tract

PyrOl i lani u~ Oor\,,1mOlar nucleus or" X H)'po~kJSS

Itoo'~!!lj!)n

~

in ;>1 coni (0) J..

~" I ~

-­

,. Pet!.in,

c,1!!I!'lI

Mu ,cI< \,,,",, i nlerc.ostal

memb rane on externa l inte rcostal m.

Transversus abdominis

Co llateral bra nc h

rejoin ing main ''','leiio' cutaneous br,1nch

'''''",,' cutilneous branch Jnd il nterior

cutaneous branc h Communica tin g branch

of interco stal n. Internal intercostal m.

fxteroal

-=01 "'ill n.

~::: ',"ot;: ':;:'::I~ I m. membmne

External

oblique m.

E 1.17: THORACIC NERVES _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ __ _ __

_ ")airs of thoracic nerves are derived from .;"aJ and ventral roots of their correspond ing ~. These nerves do not form plexuses; they e cu taneous branches to the thoracic def­ IE'5 anel send other sensory fi bers to deeper ;;:Iruc tures, vessels, the periosteum,

parieta l pleura, the peritoneum, and breast tissue. Th e th o racic nerves also send motor fibers to mus­ cl es o f the thoracic and th e abdominal walls and carry preganglionic and postganglionic sympa­ thetic nerve fibers into and ou t of the sympathetic cha in.

101

Peripheral Nervous System (PNS)-Somati
l.:.

.'lJJ part of

:' om T ~

Medial cutaneous nerve of forearm \C8, 11 )

'""\o:!.O.. !oculaneous ~g u s

( 'J­

( aiE'f1e ........

.....e

- B lrco,~"

Lateral cuta neous ne rve of forearm (CS, 6, !7l) (terminal part of muscu/a­ cutaneous nerve)

"­ Ulnar nerve (C8, T1)

---,-A.'---.."

r....

branch

Dorsal branch and dorsa l digital branches

Radial nerve Superficial branch and dorsal digital branches (C6, 7, 8)

/f'.I hna, digital branches

c- . C' Median nerve

C5

~~'- Proper pa lmar

~

C

....-,," _ :.JJ branches ~

C: - 8)

digital branches Nale: Division variable between ulnar and radial innervalion on dorsum 0 1 ha nd and often aligns wi th middle of 3rd digit instead of 4th digit as shown

:E 11.19: CUTANEOUS INNERVATION OF TH E UPPER LIMB _ _ _ _ _ __ _ _ __ -" eous innervatio n of the limb derives musculocutaneous, axillary, radial, dn d uln ar nerves. These nerves are the - bra nches of th e brachial plexus. Unlike the re rv e roofS, the cutaneous senso ry distribu-

·-if

tio n of these periph eral nerves to th e upper limb does not overlap. Thus, a peripheral nerve inj ury or compression results in a zone of anesthesia corre­

spondin g to its distribution.

REGIONAL NEUROSCIENCE Dorsa l scapular n('rve

Periphe ral Nervous System (PNS )-So ma tir: Dorsal Scapular Ner \l~ «(5 ), Suprascapular Nerve «(5, (6),

Suprascapular nerve

A)(iliary Nerve (C5, (6) and Radial Nerve «(5, (6, (7, (8; T1) Above Elbow (viewed from behind )

Supra5pil,,,tu s m.

/Deltoid m.

levator scapulae m.

(supplif'd alpaIOCYle~

Spleen Supenor afld inferior nle5el"llenc I/,J.ngfla

Mesen te rrc lymph nodc~ GALT (e. g., Peyer's patches l wil h

parasympa thetic intramural gangliJ.

J....----­ - --------- --- - --///:>';'-4'~ ~

" Plerygopalilline ganglion

I.acrimal glilnd~ Nasal m UC05.)1 gla nd~

Subma nd ibula r ganglion

Submandibular gland Sublingu.11 !!Iand

( rilni,JI n. V II

4--=-

... . atory - ~cleus

,-.

I'·

'~

",. (.-c:-:r~.::-,

I...~: .~ .. ,

Qli
FIGURE 11 .42: THORACIC SYMPATHETIC CHAI N AND SPLANCHNIC NERVES _ _ _ _ __ The sympathetic chain is a conection of sympa­ thetic ganglia that receive inpu t from the thora­ co lumbar preganglionic nerve fibers derived from the spinal cord_ The ganglia, interconnected by nerve trunks, are located in a paravertebral array from the neck to the coccygeal region. Postgan­ gli o ni c noradrenergic nerve fibers from the sympa-

126

Ihelic chain supply effecto r tissue in the periphery. Some preganglioni c nerve fibers do not synapse as they trave l through the sympathetic chain. These fibers co ntinue along th e splanchni c nerves to synapse in co llateral gangli a, wh ich supply noradrenergic innervation to effec tor ti ss ue in th e viscera.

REGIONAL NEUROSCIENCE

·pheral Nervous System (PNS)- Autonomic From hypoth alamic !

and higher centers !

,

\~~, ~~;t:~f~::;: to smooth mU$(le alld glan&;; alfer ent

i, , tracheobronchial muco~.a, and alv~oli) GI~ ,oph"y n"

Jescending tracts in spinal cord

--\ -

­

.. nerve (I X)

Affer ent nerves from 1t"C~~ n~e and sinuses (via ~ trigeminal (VI and glossopharyngeal [IX1 nerves) may also initiate renex~ in airway~

SuperiOl cervical sympathetic ganglion

'coo Symp"h.'lk nerves {adrenergic)

Caro tid

Larynx

body-\b-lfJJ

-~ ofacic

,a cord

,..--->.

art""

Sympathetic trunk -

--It

.athetic l'ibeN - -- - Preganglionic • • - - - - Postganglio nic ~""mpathetic

Cough receptors

Pulmonary p \ ,'"" "--

l'ibf:rs

- - - - Preganglionic - - - - - - Postganglionic ~ nt

fibers

·,energic lerminals (norepinephrine

I'd or epinephrine)

:-'"IOlinergic terminals (acetylcholine)

RE 11.43 : INNERVATION O F TH E TRACHEOBRONCHIAL TREE _ _ __ _ __ _ __ - 5\ mpa thetic

(noradrenergic) and parasympa­ M: cholinergic) innervation supply smooth -'e of th e tracheobron chial tree. Sympath etics e !rom th e sympatheti c chain, and parasympa­ - derive from vagal autonomic input to local lUral gangli a. Sympathetic influences result in -oc:hodilati on, and parasympathetic influences

result in bronchoco nstriction. Additional n euro~ peptidergic innerva tio n, some as co-localized o r in dependent autono mi c fibers an d some as pri· mary afferent fibers, a!so di stributes alo ng the epithelium and among the alveoli, where it ca n influence innate immune reactivity and the pro­ duct ion of infl amma tory media tors.

12 7

REGIONAL NEUROSCIENCE

Peripheral Nervous System (PNS)- Autonomic

Dorsal vagal

Su perior cervical sympathetic

Iract nucle us

t

tru nk ganglion

: ~J.

Superior cervical sympathe tic

'>'.

card iac nerve

Supe rior cervical vagal

cardiac branches Middle cervical sympalhe lic

tr unk ga nglion

Mid dle cervical sympathetic - - - -if(­

cardiac nerve

Verte bralgangl ;;,o:O:.::=======~~~J Ansa subclavia-

Cervicothoracic (5Ie))ale) ganglion

Ventral ramus o f T 1 - - - - - ­ (intercos ta l n.J

Inferior cervical sympalhelic--­

~

cardiac nerve

,'

2nd th oracic sympathet ic tru nk ganglion Thoracic vagal cardiac branch -

;:;;.:;

White ram i communicantes
corpora cavernosa of the clitoris, and supply the vestibular glands.

.....I Co,d

REGIONAL NEUROSCIENCE Nuclear cell columns

Laminae of Rexed

,-~-----------~------------~~~-------~,------~~

N udt:us posterior margin<JHs

(mllrginlI1 a l

\\,

reticlIl;Jr zan",

iof"mcdio lilleral cell o"iITln; sympathetic

:-:.lnglio nic neurons

~~iecliom('di(;les c:md Ruffin i terminals

- - AS and C tibers irom fre!? nerve

~nd ings

Alphil illo tor r'u=uron to extrafu sal

muscle fibe r end piOlte5 Gilmma motor neuron to inlraiu ;al muscle fiber end pla tes

II

(A ~)

--Intra(u sal muscle fib ers

/"

fiber irom fl o wer spra y e ndi ngs

" - yl plilleend lngs

la IAn) tIber from annulospiral endings

- - - - s h l ? ath , - - - - l vmph . ,pace Nudear bag fil ter

Detai l of muscle sp indle

~fp c lCuN "'--;,' ,:

' Nuclear ~isIJn Cf;". Tenoon organ aCli\B Ie\,

1/

Spinal trac t

C NV ~

'iF

Nudeus cuneatus -',\

~"",--.c;'r\- Tra c tu 5 soli tanus

Spinal nucleus

CN V

,

-

---f-- D o rsal m Olor

Nucleus ambiguus ---.I. - 't-__ Ven tral spinocerebellar lrael ./

SpinOl halamiC/

nucleus of X

-J- Nucleus eN Xli

'l

V"- Medial lo ngiludinal fasd culus

'tract ",""'eli",'" /~'l' - ---', Do rsal accesso ry olive

Medial accessory o live

Py ramid

pyramids" Nucleus solilarius

.I_"COW:~ ._ I 'Wi m

Section 2: Medulla- Level of the Dorsal Column Nuclei

FIGURE 11.63: BRAIN STEM CROSS-SECTIONAL ANATOMY _ _ _ _ _ __ _ _ __ _

150

REGIONAL NEUROSCIENCE

Sie m and Cerebellum

Nucleus runeatus

External (lateral) cu nea te nucle us Inferior cerebella r peduncle ~vit do rsal spinoce rebellar trac! ~

Tractus Level of section

Nucleus gracilis

r .

Nucleus S(IIit.Jrlius

/ - (:eo,,,1canal

.

nucleus

',. ~."l'1

X

Nucleus eN XII

' , ~

SOlitar~jUs: