Understanding Muscles: A practical guide to muscle function

Understanding

MUSCLES A practical guide to muscle function

Bernard Kingston

Iml

CHAPMAN iii HALL

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Unde standing MUSCLES A practical guide to muscle function Bernard Kingston For many it is a challenging task to learn and remember the functional anatomy of muscles. Understanding Muscles addresses this using an interactive learning approach where the reader is required to shade or highlight the muscles where indicated on skeletal outlines. A comprehensive introduction shows the reader how to make the most of this accessible book. Following this is a general chapter on muscles and movement. In subsequent chapters each muscle is detailed and placed in the context of the joint over which it operates. The key features of this text include: •

practical exercises and muscle tests to demonstrate the function of each muscle

•

clear explanatory diagrams to illustrate each muscle and its attachments

•

clear learning instructions and discussion points to

•

translation of the Latin names for all the muscles

be used when studying with a colleague covered This practical and informative book is essential for learning, revision and practice. It will feature on the reading list for students in phYSiotherapy, osteopathy, sports science, occupational therapy, chiropractic, nursing and sports medicine. Qualified practitioners in these areas will find this book an invaluable source of reference. Bernard Kingston is Senior Lecturer in Functional Anatomy and Clinic Tutor at the British School of Osteopathy, London, UK.

ISBN 0-412-60170-2

II I I 9 780412 601705

CHAPMAN &. HALL London· Weinheim . New York Tokyo· Melbourne· Madras Distributed in the United States by Singular Publishing Group Inc., San Diego, California ISBN 1 56593 123 8 (USA only)

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Understanding Muscles

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Understanding Muscles A

practical guide to muscle function

Bernard Kingston MA (Oxon), PGCE, DO, MRO Lecturer in Functional Anatomy, The British School of Osteopathy, London, UK Registered Osteopath

980381 CHAPMAN & HALL MEDICAL London· Weinheim . New York· Tokyo· Melbourne· Madras

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'What a piece of work is a man!' William Shakespeare Hamlet: Act 2, Scene 2

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Contents

Preface

ix·

Acknowledgements

xi

mustration acknowledgements

xiii

1

Introduction: how to use this book

2

Anatomical terminology and movements

3

Muscles and movement

4

The shoulder

5

The elbow

6

The wrist

59

7

The hand

71

8

The hip and pelvis

9

The knee

1

9

21

45

95

125

10

The ankle

11

The foot

12

The respiratory {and abdominal} muscles

13

The muscles of the vertebral column

14

The temporomandibular joint

141

153

References

167

187

215

Glossary of terms and abbreviations

Index

5

227

235

237

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x

Preface

undue force which might lead to injury should be avoided. If in doubt, avoid the muscle tests, or seek qualified advice first. Neither the author nor the publisher can be held responsible for any injury sustained while performing any tasks described in this book. It is difficult when writing a practical book on muscles to know what to leave out. This book deals only with voluntary skeletal muscle. Furthermore, it is deliberately concerned with those muscles which act on the main joints of the body. The reason for this is that the interactive approach which is adopted here tends to work best if the student can shade lines between attachment points passing over bony levers. This includes the majority of muscles in the human body. I felt that this approach might be less suitable for the more intricate muscles of the uro­ genital region, as well as the face, eye, tongue, throat and so on. I am keeping an open mind on this, and will consider the possibility of remedying this deficiency in the future. However, for the moment the book does not deal with every muscle in the human body, and I apologise for any irritation that this may cause. The fault lies entirely with my own judge­ ment on the practical scope of this particular work. Where omissions have occurred, I hope nevertheless that the reader will be encouraged to look at muscles in a different and more interactive way, and perhaps adopt the investigative approach which is used here. Finally, if the reader is able to gain as much insight and enjoyment from the reading as I have from the writing, then the task will undoubtedly have been worthwhile. I hope that this is the book that you have been waiting for. Bernard Kingston

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Acknowledgements

I should like to express my thanks and gratitude to the follow­ ing people for their help and support either as friends, col­ leagues, teachers or students. John and Dinah Badcock; Sally Champion; Simon Curtis; Jonathan Curtis-Lake; Dr Martin Collins; Maxine Dadson; Gabrielle Dowdney; Derrick Edwards;

Lisa

Fraley;

Laurie

Hartman; Alison Jesnick; Brian Joseph; Robin Kirk; Alain Lebret; Robin Lynam; Stephen Lusty; Lynne Maddock; Peter Mangan; Rosemary Morris; Hubert and Diana Moore; Doreen Ramage; Stephen Sandler; Christopher R.A. Smith; Steen Stef­ fensen; Catherine Walker; Brad Wilson; the staff at Chapman & Hall; and finally, all my past and present students at the British School of Osteopathy for their unwavering friendliness and good humour. Without them, this book would not have been possible.

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Illustration Acknowledgements

We would like to thank the following publishers for permission to adapt material. We made every effort to contact and acknow­ ledge copyright holders, but if any errors have been made we would be happy to correct them at a later printing. Green, J.H. and Silver, P.H.S. (1981) An Introduction to Human Anatomy, Oxford University Press, Oxford. Hertling, D. and Kessler, R. (1990) Management of Common Musculoskeletal Disorders 2nd edn, J.B. Lippincott Company, Philadelphia. Kapandji, LA. (1987) The Physiology of the Joints, Churchill Liv­ ingstone, London. Kapit, W. and Elson, L. (1977) The Anatomy Coloring Book, Harper and Row. Snell, R.S. (1995) Clinical Anatomy for Medical Students 5th edn, Little, Brown and Company, Boston. Williams and Warwick (eds) (1980) Gray's Anatomy 36th edn, Churchill Livingstone, London.

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Chapter 1

Introduction: How to use this book

The aim of this book is to encourage you to discover how and why certain muscles move the body in the way that they do. You will be encouraged to participate in the learning process by shading lines between the designated muscle attachments, so that the dynamic action of the muscle is appreciated. It is my belief, based on my experience as a teacher, that students learn the functions of muscles more effectively when they interact with a multi-dimensional diagram. All too often students are to be found gazing at an illustration where the details of a muscle (and often a large number of muscles) have been added. This is neither interactive nor stimulating, and the student does not find the muscle functions easy to learn or comprehend. This book adopts a different approach. Only the attachment points of an individual muscle are shown on a skeletal outline. The essential muscle details are given for reference purposes, and this is followed by a number of practical study tasks. In each case you will be encouraged to 'learn by doing' and par­ ticipate in the following activities: • Shading lines between the attachment points indicated,

and considering the muscle functions which are listed in the text.

• Either self-testing and/or observing the muscle functions

on your own body, or a colleague as appropriate. 'Colleague' can of course be taken to mean anyone who is suitable and willing, but obviously frail or otherwise unsuitable subjects should not be asked to participate, for proper reasons of safety. The normal rules of professional conduct and commonsense should apply.

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Intercostal nerves 2-5.

Function •

The attachment points suggest that ribs 2-5 will be elevated in deep inspiration, but there is some uncertainty over this I Gray's Anatomy, 1995).

Study task •

Shade lines between the attachment points and consider the muscle function.

Quadratus lumborum ('square­ shaped muscle of the low back')

Attachments • •

Iliolumbar ligament and posterior aspect of the iliac crest. Inferior border of the twelfth rib and TPs of T12 and L1-4.

NeIVe supply Ventral rami of T12; L 1-3, (4).

Functions •

As an accessory muscle of inspiration it fixes the twelfth rib,

• •

Bilaterally, is assists extension of the lumbar spine.

providing a stable border for the descending diaphragm. Unilaterally, it assists sidebending of the lumbar spine.

Study tasks •

Shade lines between the attachment points and consider the functions of the muscle.

•

Test the muscle by placing a colleague in the prone position with their extended legs slightly sidebent Palpate with one hand below their twelfth rib while your other hand prevents them from straightening their body. This test is limited only to the sidebinding function.

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The mechanism of breathing

Expiration In expiration the exhalation of air from the lungs occurs as a result of natural recoil, gravity and the graded relaxation of the muscles of inspiration. As with inspiration, there are a number of muscles whose attachments appear to be helpful in the res­ piratory process and yet whose role is still not fully substanti­ ated. A number of muscles would seem to assist quiet expiration, while forced expiration may require expulsive effort which recruits the powerful abdominal muscles anteriorly and latissimus dorsi posteriorly.

Movements of the thorax during expiration

Primary muscles

Descent of clavicle and upper ribs

Descent of sternum

•

intercostales interni (pp. 179-180)

•

transversus thoracis (pp. 180-181)

Accessory muscles

and reduction of AP diameter

Flexion of thoracic spine aids expUlsion

Ribs descend

8

•

serratus posterior inferior (p. 181)

•

latissimus dorsi (p. 182)

•

iliocostalis lumborum (p. 203)

•

longissimus thoracis (p. 201)

•

abdominal muscles (p. 182)

•

subcostales (p. 180)

Diaphragm returns to position of rest

StudytBsks •

Highlight the names of the features indicated including the names of the muscles.

•

Study the details of each muscle with reference to the page number given.

The primary muscles of expiration These muscles are always used, including during quiet breathing.

Note: Deep to this muscle lies the intercostalis intimus muscle ('deepest muscle between the ribs') which runs in the

Intercostales interni ('inner

same direction and appears to perform the same function. It

muscles between the ribs')

occupies the middle section of the intercostal rib space, but is

(Eleven on each side.)

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179

180

The respiratory (and abdominal) muscles

poorly developed in the upper ribs. The .ubcostal•• ('the muscles under the ribs') are also deep and variable fasciculi which are thought to help depress the ribs in expiration. There is, however, uncertainty about the precise role of some of these muscles (Gray's Anatomy 1995).

To sternum