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HUMAN BIOLOGY – MODULE: MUSCULOSKELETAL ANATOMY

Student Manual

HLT42015 CERTIFICATE IV IN MASSAGE THERAPY

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Human Biology – Module MSA 1 V16.03 www.studymassage.com.au 1300 880 885

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CONTENT Assessment ........................................................................................................................ 6

Practical Assessment............................................................................................................................................... 6

The Skeletal System ....................................................................................................... 7

1. Types of Bones ................................................................................................................... 7

2. Appendicular and Axial Skeleton ............................................................................... 8

2.1 Axial Skeleton ................................................................................................................................................ 9

2.2 Appendicular Skeleton ............................................................................................................................ 14

3. Bone Markings ................................................................................................................ 19

3.1 Vertebrae ...................................................................................................................................................... 21

3.2 Pectoral Girdle ............................................................................................................................................ 22

3.3 Upper Limb .................................................................................................................................................. 25

3.4 Pelvic Girdle ................................................................................................................................................ 29

3.5 Lower Limb .................................................................................................................................................. 31

The Articular System .................................................................................................. 39

4. Classification of Joints .................................................................................................. 39

4.1 Fibrous Joints .............................................................................................................................................. 39

4.2 Cartilaginous Joints .................................................................................................................................. 39

4.3 Synovial Joints ............................................................................................................................................ 40

5. Types of Synovial Joints .............................................................................................. 41

5.1 Plane Joints .................................................................................................................................................. 41

5.2 Hinge Joints.................................................................................................................................................. 41

5.3 Pivot Joints ................................................................................................................................................... 41

5.4 Condyloid (Ellipsoid) Joints .................................................................................................................. 41

5.5 Saddle Joints ................................................................................................................................................ 42

5.6 Ball and Socket Joints .............................................................................................................................. 42

6. Synovial Joint Movements .......................................................................................... 43

6.1 General Movements ................................................................................................................................. 45

6.2 Special Movements ................................................................................................................................... 48

6.3 Additional Movements ............................................................................................................................ 53

7. Characteristics of Body Joints ................................................................................... 57

7.1 In Summary ................................................................................................................................................. 57

The Muscular System ................................................................................................. 61

8. Introduction to Skeletal Muscle ............................................................................... 61

8.1 Basic Structure of Skeletal Muscle ..................................................................................................... 61

8.2 Types of Skeletal Muscle ........................................................................................................................ 62



8.3 Types of Muscle Attachments .............................................................................................................. 62

8.4 Integration of Muscle Action ................................................................................................................ 62

8.5 The Role of Muscles in Movement...................................................................................................... 63

8.6 Types of Muscle Contractions .............................................................................................................. 64

8.7 Naming Skeletal Muscles........................................................................................................................ 65

9. Major Muscles of the Body ......................................................................................... 66

9.1 Muscles of the Upper Back .................................................................................................................... 69

9.2 Muscles of the Neck .................................................................................................................................. 72

9.3 Muscles of the Shoulder ......................................................................................................................... 75

9.4 Muscles of the Arm ................................................................................................................................... 82

9.5 Muscles of the Chest ................................................................................................................................. 89

9.6 Muscles of the Abdomen ........................................................................................................................ 93

9.7 Muscles of the Lower Back .................................................................................................................... 97

9.8 Muscles of the Buttock ..........................................................................................................................101

9.9 Muscle of the Posterior & Lateral Leg ............................................................................................105

9.10 Muscles of the Anterior and Medial Leg .......................................................................................112

Overview ....................................................................................................................... 119

10. Review ............................................................................................................................. 119

10.1 The Skeletal System ...............................................................................................................................119

10.2 The Articular System .............................................................................................................................124

10.3 The Muscular System ............................................................................................................................126

11. Muscle Groups .............................................................................................................. 127

11.1 Muscles of the Anterior Neck .............................................................................................................127

11.2 Deep Muscle Group of the Back .........................................................................................................127

11.3 Muscles of the Posterior Abdominal Wall .....................................................................................127

11.4 Muscles of the Anterior Abdominal Wall ......................................................................................127

11.5 Muscles of the Thorax involved in Respiration ..........................................................................128

11.6 Muscles of the Gluteal Region ............................................................................................................128

11.7 Muscles of the Scapular Stabilisation .............................................................................................128

11.8 Muscles of the Rotator Cuff Group ...................................................................................................128

11.9 Muscles which cross the Shoulder Joint ........................................................................................128

11.10 Muscles which cross the Elbow Joint ..............................................................................................131

11.11 Muscles of the Posterior Thigh ..........................................................................................................131

11.12 Muscles of the Medial Thigh ...............................................................................................................131

11.13 Muscles of the Anterior Thigh............................................................................................................131

11.14 Muscles which cross the Hip Joint ....................................................................................................131

11.15 Muscles of the Anterior and Lateral Lower Leg .........................................................................131

11.16 Muscles of the Posterior Lower Leg ................................................................................................131



12. Muscle Actions ............................................................................................................. 135

12.1 Muscles Acting on the Arm ..................................................................................................................135

12.2 Muscles Acting on the Leg ...................................................................................................................135



Assessment

Welcome to your Human Biology –Module: Musculoskeletal Anatomy Manual.

In this manual you will find details of the theory components of your subject which relate to

assessments you will then be required to complete or answer.

Assessments play an important role. At Evolve College they are not pressured or designed to create

stress. We implement assessments to support you in your learning. The assessments are a

demonstration to you, and to us, that you have learned what is needed to ensure you complete your

course with the readiness to work as a valued member of the industry. We structure the assessments

in a way that supports you.

Depending on the subject, the type and number of assessments will vary, and may include theory

assessments such as Multiple Choice, Short Answer, True/False questions; Matching Exercises;

Assignments, Project Reports and practical assessments such as Role plays and Demonstrations.

Access your assessments via the Student Portal - Student Login on the bottom of the Homepage.

Answers will only be accepted and recorded through the Student Portal.

Practical Assessment

This subject requires you to undertake several practical assessments. These will be in the form of role

plays, demonstrations and clinical massage treatments at Massage Practice 1.



The Skeletal System

1. Types of Bones

Bones are classified according to shape not size. The unique shape of each bone fulfils a particular need. For example, the femur (thigh bone) is designed to withstand great pressure and its hollow cylindrical shape provides maximum strength with minimum weight.

Type Description Examples

1. Long Considerably longer than they are wide. Consist of a shaft plus two ends.

Thigh Forearm

2. Short Roughly cubelike. Wrist Ankle

3. Flat Thin, flattened. Skull Ribs

4. Irregular Fit none of the above. Vertebrae Pelvis

3

4

1

2

3

4



2. Appendicular and Axial Skeleton

For the purpose of study, the 206 bones of the human skeleton are divided into 2 portions: the axial and appendicular skeletons.

The AXIAL SKELETON supports and protects the head, neck and trunk and consists of the bones related to the axis of the body. The axis is an imaginary longitudinal line that runs through the head and down to the space between the feet. This straight line runs vertically along the body's centre of gravity and is considered the centre of the human body.

The APPENDICULAR SKELETON produces most of the body's movements and consists of the bones of the upper and lower extremities (free appendages) and the bones (girdles) that anchor them to the axial skeleton.

- Color in the Axial Skeleton and the Appendicular Skeleton.

Axial Skelton

Midline



2.1 Axial Skeleton

1. Skull

The adult human skull rests on the superior end of the vertebral column and contains several cavities that house the brain and sensory organs.

a. Cranial Bones - are all interlocked by sutures and enclose and protect the brain and the sensory organs of sight, hearing and balance.

i. Frontal bone / forehead forms the forehead and roof of the nasal cavity.

ii. Parietal bones (2) form superior sides of the cranium and the roof of the cranium.

iii. Temporal bones (2) form inferior sides of the cranium and part of the cranial floor.

iv. Occipital bone forms the posterior portion of the skull and the prominent portion of the base of the cranium.

v. Sphenoid bone is the "keystone" of the cranial floor as it articulates with all other cranial bones and forms the anterior base of the cranium.

vi. Ethmoid bone forms the roof of the nasal cavity.

b. Facial Bones - form the framework and basic shape for the face.

i. Maxilla / upper jaw (2) articulates with every bone of the face.

ii. Palatine bones (2) form the posterior portion of the hard palate which separates the upper nasal cavity from the lower oral cavity.

iii. Zygomatic bones / cheekbones (2) articulates with the temporal bone forming the zygomatic arch.

iv. Lacrimal bones (2) are the smallest bones of the face and allow the passage of tear ducts into the nasal cavity.

v. Nasal bones / nose (2) forms the bridge of the nose.

vi. Inferior Nasal Concha (2) form portions of the lateral walls of the nasal cavities and allows for circulation and filtration of air before it passes into the lungs.

vii. Vomer bone forms the inferior and posterior part of the nasal septum.

viii. Mandible / lower jaw is the only moveable bone of the skull.

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- Referring to your DVD color and label in the parts of the Skull represented by the three views below.

Anterior View

Lateral View

Inferior View

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2. Vertebral Column and Vertebrae

The Vertebral Column is commonly called the "backbone/spine" and along with the spinal cord is referred to as the Spinal Column. The linking of the vertebrae through intervertebral discs, interlocking processes and binding ligaments permits limited movement between vertebrae but extensive movements of the entire vertebral column.

a. Cervical Vertebrae (7) form the flexible framework of the neck region and support the head (C1 - C7). Two specialised cervical vertebrae are the Atlas (C1) and the Axis (C2).

b. Thoracic Vertebrae (12) serve as attachments for the ribs (T1 - T12).

c. Lumbar Vertebrae (5) are the largest vertebrae and enable attachment of powerful

back muscles (L1 - L5).

d. Sacrum (5 fused = 1) is a triangular, wedge-shaped bone providing strong foundation for the pelvic girdle.

e. Coccyx (4 fused = 1) is a rudimentary, reduced bony structure.

- Referring to your DVD, label and color in the parts of the vertebral column.

3. Thoracic (Rib) Cage

The Thoracic Cage is involved directly in the mechanics of breathing, encloses and protects the thoracic viscera and also supports the pectoral girdle and upper extremities.



a. Sternum / Breastbone forms the anterior midline of the upper thorax and attaches to the costal cartilages of the first seven ribs.

The Sternum consists of the: i. Manubrium

ii. Body iii. Xiphoid Process

b. Ribs (12 pairs) attach posteriorly to a thoracic vertebrae and anteriorly.

The ribs consist of: i. True Ribs (first 7) attached directly to the sternum.

ii. False Ribs (8th, 9th & 10th) attach indirectly to the sternum. iii. Floating Ribs (11th & 12th) have no association with the sternum.

- Referring to your video clips, label and colour in the parts of the thoracic cage.



4. Middle Ear Ossicles

The middle ear ossicles are the smallest bones in the body and are technically considered a separate group of bones - apart from the axial and appendicular skeletons, but placed in the Axial classification for convenience.

These bones are named for their shape: a. Malleus / hammer b. Incus / anvil c. Stapes / stirrup

5. Hyoid

The Hyoid bone is unique among all bones of the skeletal system in that it is the only bone that does not articulate directly to any other bone. It is located in the neck between the mandible and the larynx (voice box).

Hyoid Bone



2.2 Appendicular Skeleton

1. Pectoral (Shoulder) Girdle

The Pectoral Girdle is non-weight bearing and provides attachment of many muscles that move the arm allowing great mobility. It is not a complete girdle because it attaches to the axial skeleton at only one point which is at the sternum.

a. Clavicle / collarbone binds the shoulder to the axial skeleton and is responsible for maintaining the normal height of the shoulder.

b. Scapula / shoulder blade is a large, flat triangular bone and has 15 muscles attached to

it.

- Referring to your video clips, label and colour in the parts of the shoulder girdle (Note: the diagram is an anterior view of the right pectoral girdle).



2. Upper Extremities

The two appendages attach to the shoulder and consist of the arm, forearm wrist and hand.

a. Humerus / upper arm is the longest and largest bone of the upper extremity and articulates with the glenoid fossa of the scapula.

b. Ulna is the lower arm on the little finger side, ie. medial side.

c. Radius is the lower arm on the thumb side, ie. lateral side.

d. Carpals / wrist bones are arranged in two transverse rows of four each.

Proximal Row - lateral to medial i. Scaphoid - shaped like a boat

ii. Lunate - half-moon shaped surface iii. Triquetrium - shaped like a right triangle iv. Pisiform - shaped like a pea

Distal Row - lateral to medial i. Trapezium - "a little table"

ii. Trapezoid - "table-shaped" iii. Capitate - has rounded head iv. Hamate - has curved, hooklike process called

the hamulus e. Metacarpals / hand bones are numbered 1-5 from

the thumb (lateral) side.

f. Phalanges / fingers consist of 14 bones forming a total of 5 digits.

- Referring to your video clips, label and colour in the carpal bones shown above (Note: the diagram is a palmer/anterior view of the left hand).

- Referring to your video clips, label and colour in the parts of the upper limb (Note: the diagram is an anterior view of the right upper limb.)



3. Pelvic Girdle

The Pelvic Girdle formed by the union of 2 Ossa Coxae. Each Os Coxa develops as three separate bones and are fused together in the adult. However they are considered separate for descriptive purposes.

a. Ilium / hip is the large superior portion b. Ischium / sitting bone is the inferior and posterior portion c. Pubis / pubic bone is the inferior and anterior portion

The Pelvis itself is a basinlike bony structure which consists of the Pelvic Girdle (2 Ossa Coxae) and the sacrum and coccyx of the vertebral column and the symphysis pubis.

- Referring to your video clips, label and color in the parts of the pelvic girdle shown below (note: the diagram includes the sacrum and the coccyx which are part of the vertebral column).

Anterior View



4. Lower Extremities

The two appendages attach to the pelvis and consist of the thigh, leg, ankle and foot.

a. Femur / thighbone is the longest, heaviest and strongest bone of the body.

b. Patella / kneecap is a small triangular bone which protects the knee joint.

c. Tibia / shinbone is the larger of the two bones of the leg.

d. Fibula / splint bone is a long, narrow bone parallel and lateral to the tibia.

e. Tarsals / ankle bones consist of seven bones: i. Talus - the only tarsal bone involved in forming the

ankle joint ii. Calcaneus / heel bone - the largest of the tarsal bones

and posterior to the talus iii. Navicular - boat-shaped and anterior to the talus. iv. 4 Distal bones of the ankle consisting of (medial to

lateral): - 1st, 2nd & 3rd Cuneiform (wedge-shaped) - Cuboid (anterior to the Calcaneus)

f. Metatarsals / foot bones are numbered 1-5 from the big toe (medial) side.

g. Phalanges / toes consist of 14 bones forming a total of 5 digits.

- Referring to your video clips, label and colour in the tarsal bones shown above (note: the diagram is a dorsal/superior view of the right foot).

- Referring to your video clips, label and colour in the parts of the lower limb (Note: the diagram is an anterior view of the right lower limb).



Tally the total number of bones found in the Axial Skeleton and Appendicular Skeletons by

totalling up the number of individual bones found in each region.

Axial Skeleton

Skull 22

Cranial ? Frontal ? Parietal ? Temporal ? Occipital ? Sphenoid ? Ethmoid ?

Facial ? Maxilla ? Palatine ? Zygomatic ? Lacrimal ? Nasal ? Inferior Nasal Concha ? Vomer ? Mandible ?

Middle Ear Ossicles 6 Malleus ? Incus ? Stapes ?

Hyoid 1

Vertebral Column 26 Cervical ? Thoracic ? Lumbar ? Sacrum ? Coccyx ?

Thorax 25 Sternum ? Ribs ?

Total no. of bones 80

Appendicular Skeleton

Pectoral Girdle 4 Clavicle ? Scapula ?

Upper Extremity 60 Humerus ? Ulna ? Radius ? Carpal ? Metacarpal ? Phalanges ?

Pelvic Girdle 2 Os Coxa ?

Lower Extremity 60 Femur ? Patella ? Tibia ? Fibula ? Tarsal ? Metatarsal ? Phalanges ?

Total no. of bones 126

Total Number of bones in the body: Axial Skeleton: 80 Appendicular Skeleton: 126 206



3. Bone Markings

Skeletal Terms (refer to diagram following for examples)

1. Tubercle

a small eminence or swelling ie. a small bump, eg. bump on lateral humerus

2. Tuberosity

a small rounded eminence ie. a knob, eg. bump on front of the tibia below knee

3. Trochanter

a large bony eminence, eg. bump on the side of femur below hip

4. Foramen

an opening or hole, eg. opening at base of the pelvis

5. Spine

a bony process, especially if long and relatively narrow, eg. spine of scapula

6. Process

a projection from a structure, eg. sideways projection of vertebrae

7. Fossa

a pit or depression in a structure, eg. depression on anterior surface of ilium

8. Cavity

a socket, eg. cavity of the eye

9. Groove

any furrow or elongated depression ie. a channel, eg. groove on front of humerus

10. Crest

a ridge-like bony process, eg. ridge along the top of pelvis

11. Body

the main section of a bony part, eg. body of sternum

12. Notch

an indentation forming a curvature in a bony structure, eg. notch at top of manubrium

13. Angle

an angle or corner, eg. angle at top of scapula

14. Border

a reasonably straight section of bone ie. a margin, eg. border on side of scapula

15. Head

a head or top, eg. head of fibula

16. Neck

a narrowing below the head, eg. neck of fibula before becoming shaft

17. Condyle

a rounded, cartilage covered bony eminence for articulation with another bone ie. knuckle-like, eg. condyle at base of femur which articulates with top of tibia

18. Epicondyle

a bony protuberance above a condyle of a bone which does not participate in

articulation, eg. are immediately above condyle of femur



Note: 5 is not shown because it is located on the posterior aspect.

4

2

3

7

8

12

1

11

6

10

14

9

13

16

15

17

18



3.1 Vertebrae

1. BODY

anterior weight bearing portion of the vertebrae

2. SPINOUS PROCESS a single midline posterior projection of the vertebrae

3. TRANSVERSE PROCESS

a projection extending from the lateral aspect of the vertebrae

2

1

3

Anterior Aspect

Superior Aspect

Inferior Aspect

Posterior Aspect

2

1

3

Posterior Aspect

Anterior Aspect

Superior View of Vertebrae

Lateral View of Vertebrae



3.2 Pectoral Girdle

CLAVICLE

1. STERNAL END cone shaped medial end which attaches to the manubrium of the sternum

2. ACROMIAL END lateral flattened end which articulates with the acromion of the scapula

SCAPULA

1. SUPERIOR BORDER shortest, sharpest border above the spine of the scapula

2. MEDIAL BORDER parallels the vertebral column

3. LATERAL BORDER abuts the armpit

4. GLENOID CAVITY small, shallow fossa which articulates with the humerus of the arm

5. SUPERIOR ANGLE where the medial and superior borders meet

6. INFERIOR ANGLE where the medial and lateral borders meet

7. SPINE sharp, prominent ridge on the posterior surface

8. ACROMION PROCESS large anterior projection at lateral end of spine of scapula which represents the tip of the shoulder

Anterior View of the Right Vertebrae

Superior Aspect

Inferior Aspect

Lateral Aspect

Medial Aspect

1 2



9. CORACOID PROCESS projects anteriorly from the superior scapular border

10. SUPERIOR NOTCH medial to the coracoid process attachment to the scapula

11. SUPRASPINOUS FOSSA large, shallow depression above the spine

12. INFRASPINOUS FOSSA large, shallow depression below the spine

13. SUBSCAPULAR FOSSA concavity of the anterior scapular surface

14. SUPRAGLENOID TUBERCLE bump above the glenoid cavity

15. INFRAGLENOID TUBERCLE bump below the glenoid cavity

Posterior Aspect

Lateral View of Right Scapula

Anterior View of Right Scapula

13

6

12

2

8

4

15

3

9

14

10

5

1

11

Superior Aspect

Inferior Aspect

Anterior Aspect

Posterior View of the Right Scapula



Inferior Aspect

Superior Aspect

Lateral Aspect

Medial Aspect

5

9 8

1

4

6

3 2

7

11

12

15

14



3.3 Upper Limb

Humerus

Proximal End

1. Head smooth and hemispherical, proximal end of humerus

2. Neck slight constriction immediately below the head

3. Greater Tubercle inferior and lateral to the acromion process

4. Lesser Tubercle inferior and medial to the acromion process

5. Intertubercular Groove between the greater and lesser tubercle also referred to as the bicipital groove

Shaft

6. Deltoid Tuberosity roughened attachment site midway down the shaft on the lateral side

Distal End

7. Trochlea a medial pulley-shaped condyle, articulates with the ulna

8. Capitulum a lateral ball-like condyle, articulates with the radius

9. Medial Epicondyle projection superior to trochlea

10. Lateral Epicondyle projection superior to capitulum

11. Coronoid Fossa a depression above the trochlea on the anterior surface, articulates with the coronoid process of the ulna during elbow flexion (ie. when bending the elbow)

12. Olecranon Fossa a deep depression above the trochlea on the posterior surface, articulates with the olecranon process of the elbow during elbow extension (ie. when straightening the elbow).



Inferior Aspect

Anterior View of the Right Humerus

Posterior View of the Right Humerus

Lateral Aspect

Superior Aspect

Medial Aspect Lateral Aspect

1

4 3

5

2

6

11 12

10 10 9

7 7 8



Forearm

Ulna (Proximal End)

13. Trochlea Notch the deep concavity of the ulna

14. Radial Notch small articular depression on lateral side of coronoid process

15. Olecranon Process prominent posterior process which creates the point of the elbow

16. Coronoid Process prominent anterior process below trochlea notch

Radius (Proximal End)

17. Head end of radius and shaped like the end of a spool of thread

18. Neck slight constriction immediately below the head

19. Radial Tuberosity a rough projection just distal to the head also referred to as the bicipital tuberosity

Ulna & Radius (Distal End)

20. Styloid Process of Ulna the medial projection

21. Styloid Process of Radius the lateral projection



Anterior View of the Right Radius & Ulna

Posterior View of the Right Radius & Ulna

Superior Aspect

Medial Aspect

Inferior Aspect

Lateral Aspect

20

21 21

Ulna

15

17

18

19

Ulna

Radius

Lateral Aspect

13

16

14

17

18

19

Radius



3.4 Pelvic Girdle

Ilium

1. Iliac Crest thickened superior margins of the ilium

2. Anterior Superior Iliac Spine (ASIS) a blunt projection which terminates the iliac crest anteriosuperiorly and is presented as prominent anterior landmarks at the level of the waistline

3. Posterior Superior Iliac Spine (PSIS) a blunt projection which terminates the iliac crest posteriosuperiorly and is presented as distinct dimples in the skin at the base of the lower back

4. Anterior Inferior Iliac Spine (AIIS) less prominent projection below ASIS

5. Posterior Inferior Iliac Spine (PIIS) less prominent projection below PSIS

6. Greater Sciatic Notch deep indentation just inferior to the PIIS

7. Iliac Fossa concavity of the medial surface of ilium

Ischium

8. Ischial Spine medial projection into the pelvic cavity

9. Lesser Sciatic Notch slight indentation just inferior to the ischial spine

10. Ischial Tuberosity a rough and grossly thickened inferior surface of the ischium

Pubis

11. Pubic Crest thickened anterior border of the body (medial portion) of pubis

a. Acetabulum - a deep hemispherical socket formed on the lateral surface of the coxal bone, represents the point of fusion of the ilium, ischium and pubis

b. Ilium - large flaring bone that forms the major portion of the coxal bone c. Ischium

arc shaped bone that forms the posterioinferior part of coxal bone d. Pubis - V- shaped bone that forms the anterior portion of coxal bone e. Obturator Foramen - large opening of the coxal bone formed by the pubis and

ischium.

Lateral View of the

Right Ossa Coxae (Pelvis)

a

b

d c

e



Lateral View of the Right Ossa Coxae (Pelvis)

1

3

5

6

8

9

10

2

4

11

7

Note: located on the medial aspect

Inferior Aspect

Anterior Aspect

Posterior Aspect

Superior Aspect



3.5 Lower Limb

Femur

Proximal End

1. Head ball-like end of femur

2. Neck

a short section from the head angling laterally to join the shaft

3. Greater Trochanter lateral site of the junction of the neck and shaft

4. Lesser Trochanter

medial site of the junction of the neck and shaft

5. Gluteal Tuberosity small rough area on shaft posteriosuperiorly

6. Linea Aspera

long vertical ridge on posterior surface of shaft

Distal End

7. Medial Condyle large rounded medial projection which articulates with the tibia

8. Lateral Condyle

large rounded lateral projection which articulates with the tibia

9. Medial Epicondyle flanks the medial condyle superiorly

10. Lateral Epicondyle

flanks the lateral condyle superiorly Note: The medial and lateral condyles of the femur are often referred to as femoryl condyles.

Anterior View of the

Right Femur



Superior Aspect

Inferior Aspect

Lateral Aspect

5

6

10

8

3

9

7

1

4

Medial Aspect

Note: 5 is on the posterior surface

Note: 6 is on the posterior surface

2

X



Lower Leg: Tibia and Fibula

Proximal End (Tibia)

1. Medial Condyle concave surface on medial end of tibia

2. Lateral Condyle

concave surface on lateral end of tibia

3. Tibial Tuberosity large, rough projection just inferior to the condyles on the anterior surface

Proximal End (Fibula)

4. Head upper end

5. Neck

a short section from head which joins to the shaft

Distal End (Tibia & Fibula)

6. Medial Malleolus projection on the tibia which forms the medial bulge of the ankle

7. Lateral Malleolus

projection on the fibula which forms the lateral bulge of the ankle



- The bone markings below can be identified through surface anatomy palpation. See if you can feel for these structures on someone while they are in the two positions suggested.

Inferior Aspect

Superior Aspect

Anterior View of the Right Tibia & Fibula

Lateral Aspect

5

4

2

7

3

6

1

Medial Aspect

Fibula Tibia



Prone

1. Occiput 2. C1 - C7 Nuchal Ligament 3. C7 Spinous Process 4. T3 Spinous Process (Spine of Scapula) 5. T7 (Inferior Angle) 6. T12 7. Medial Border 8. Superior Angle 9. Lateral Border 10. Lumbar Vertebrae 11. Iliac Crest (b/w L4 & L5) 12. PSIS 13. Greater Trochanter 14. Sacrum

Sitting

Shoulder & Arm

1. Acromion Process 2. Clavicle - medial 2/3rds convex; lateral 1/3 concave 3. A/C Joint 4. Coracoid Process 5. Greater Tubercle 6. Lessor Tubercle 7. Intertubercular Groove 8. Deltoid Tuberosity 9. Olecranon Process 10. Medial & Lateral Epicondyles 11. Olecranon Fossa 12. Radial Head 13. Styloid Processes 14. Pisiform 15. Scaphoid

Leg

1. Femoral Condyles 2. Head of Fibula 3. Knee joint line 4. Tibial Tuberosity 5. Malleolus



Becoming familiar with the bone names and bone marking terms will take some time. Please

use the diagrams below to test yourself.

It is important that you are confident with the bones and their markings and have a good understanding of their locations throughout the body before continuing to the next section.







The Articular System

Joints, or articulations, are sites where two or more bones meet. Our joints secure our bones together and allow our skeleton of rigid bone to be mobile. With the exception of the hyoid bone of the neck, every bone in the body forms a joint with at least one other bone.

4. Classification of Joints

Joints may be classified structurally or functionally. Structural classification focuses on the material binding the bones together and whether or not a joint cavity is present. Functional classification is based on the amount of movement allowed at the joint. There are three types of joints - Fibrous, Cartilaginous and Synovial. In general, fibrous joints are immoveable and all synovial joints are freely moveable. However, cartilaginous joints have both rigid and slightly moveable examples.

4.1 Fibrous Joints

Bones are joined by fibrous tissue and no joint cavity is present. The amount of movement allowed depends on the length of fibres uniting the bone and most fibrous joints permit essentially no movement.

4.2 Cartilaginous Joints

Bones are joined by cartilage and also lack a joint cavity, permitting only slight movement.

Sutures which join the flat bones of the skull together are examples of fibrous joints.

Intervertebral discs are an example of a cartilaginous joint.



4.3 Synovial Joints

Joints in which the articulating bones are separated by a fluid-containing joint cavity permitting substantial freedom of movement.

Structural (Shape) Functional (Movement)

1. Fibrous Immoveable

2. Cartilaginous Slightly Moveable

3. Synovial Freely Moveable

Most joints in the body are Synovial Joints. Shown here is the elbow joint.

The structure of a synovial joint is shown below. By referring to the textbook label its features.

We will now look at the different types of Synovial Joints found in the body (Structure). Because they make up most of the joints in the body they are responsible for most of its movements.

Examining the structure of synovial joints will help us understand the types of Joint Movements (Function) that are then possible.

In Summary:



5. Types of Synovial Joints

5.1 Plane Joints

Allow only short slipping or gliding movements as the articular surfaces are essentially flat.

5.2 Hinge Joints

Consists of a convex or cylindrical projection of one bone fitting into a concave surface or cylindrical groove of another. Motion is along a single plane and is similar to that of a door hinge.

5.3 Pivot Joints

Consists of a rounded or conical end of one bone which protrudes into a "sleeve" of another. Therefore allowing only the movement of one bone around its own long axis or against the other bone.

5.4 Condyloid (Ellipsoid) Joints

Consist of an articular surface of one bone fitting into a complementary concavity in another. The important characteristic is that both articulating surfaces are oval. This biaxial joint permits all angular motions.

Between the Carpal Bones. Hence, referred to as Intercarpal Joints.

The Knee joint and Elbow joint are typical Hinge Joints.

You have the ability to rotate your forearm due to the pivoting action of the radius on the ulna at the elbow. Hence this joint is known as the radioulnar joint.

You are able to move your wrist freely because of this joint. It is located between the radius (which you will notice is very wide at the distal end) and the carpal bones. Hence, the wrist joint is referred to as the radio-carpal joint.



5.5 Saddle Joints

Resemble condyloid joints but they allow greater freedom of movement. This is due to each articular surface having both concave and convex areas, ie. shaped like a saddle.

Note: The Condyloid and Saddle joints are similar in both their structure (shape) and their function (movement).

5.6 Ball and Socket Joints

Are the most freely moveable synovial joints. Universal movement is allowed due to the spherical head of one bone articulating with the concave socket of another.

You will notice that your thumb has an excellent range of movement due to being a saddle joint. The joint is between the carpal bone and metacarpal bone and is therefore referred to as the carpo-metacarpal joint.

The hip joint (shown) and the shoulder joint are the only two ball and socket joints in the body. They provide the greatest range of movement of any joints.



6. Synovial Joint Movements

Range of motion of synovial joints varies from slipping movements only to movements in and around all planes of space and axes.

Anatomical Position

The Anatomical Position is a standard body position that provides an initial reference point to help describe body parts and position accurately. Most directional terminology used in these notes and the accompanying text book refer to an individual's body as if it were in the anatomical position, regardless of its actual position. If you get confused about a particular body position or directional term always refer back to the anatomical position, because this is your starting point - in this position all joints are in EXTENSION, ie. they are straight. From this position, where the joints are extended (straight) you can then examine the movement in question. You will note that many body system charts depict the body in this position. The anatomical position is with:

- the body erect - head, eyes and toes forward - upper limbs by the sides - palms facing forward

Other positions used in anatomical description: Prone lying face down Supine lying face up Neutral the position adopted by a body part midway between two opposite positions Resting the position adopted by the body or body part where its mass is supported by an external force, eg. lying in bed or sitting in a chair Note: It is important to use the anatomical position as the point of reference in

determining specific directions of movement of joints.

Midline of the Body

On occasions the term “Midline” will be referred to when describing other body positions or directions. The midline is an imaginary line that passes through the middle of the body. Not unlike the body’s plumbline used in posture analysis.

Anatomical Position

In the anatomical position all joints are in extension (ie. straight) eg. the knee is in extension, so is the hip, also the shoulder and the head, etc.

Midline



The Synovial Joint Movements are as follows:

a. Flexion

b. Extension

c. Abduction

d. Adduction

e. Circumduction

f. Rotation

g. Supination

h. Pronation

i. Inversion

j. Eversion

k. Plantar Flexion

l. Dorsiflexion

m. Protraction

n. Retraction

o. Elevation

p. Depression

q. Ulnar Deviation

r. Radial Deviation

s. Opposition

t. Gliding

u. Lateral Flexion

v. Hyperextension

General Movements

Specific Movements

Additional Movements



6.1 General Movements

There are six general movements generated by the body. They make up most of the movements produced by synovial joints.

a. Flexion

is movement that decreases the angle of a joint and brings the two articulating bones closer together.

b. Extension

is movement that increases the angle of a joint.

Flexion bends the elbow. The angle between the forearm bones (radius & ulna) and humerus decreases.

Extension straightens the elbow. The angle between the forearm bones (radius & ulna) and humerus increases and the arm returns to the anatomical position. Remember: all joints are in extension in the anatomical position – that is, they have an angle of 180 degrees.

Hinge Joints can only perform flexion and extension movements due to their “hinge” design.

For Example: The Elbow Joint.

Flexion bends the knee. The angle between the lower leg bones (tibia & fibula) and femur decreases.

Extension straightens the knee. The angle between the lower leg bones (tibia & fibula) and femur increases, returning the leg back to the anatomical position. In this position the angle is 180 degrees, ie. straight.

For Example: The Knee Joint.

Extension

Extension Flexion

Flexion



c. Abduction

is movement of a limb away from the midline or median plane of the body and along the frontal plane.

d. Adduction

is movement of a limb toward the midline.

Condyloid Joints (eg. your knuckle joint) and Saddle Joints (eg. your thumb joint) can not only perform flexion and extension but they can also perform abduction and adduction.

For Example: The Shoulder Joint.

For Example: The Hip Joint.

Abduction

Abduction takes the arm sideways, away from the midline of the body. Think “abduct” = take away

Adduction

Adduction brings the arm sideways, towards the midline of the body. Think “adduct” = add to body

Abduction Adduction



e. Circumduction

is movement in which the limb describes a cone in space and the distal end moves in a circle.

f. Rotation

is the turning movement of a bone around its own axis.

Turning the arm in is called Internal or Medial Rotation. Turning the arm out is called External or Lateral Rotation.

You have the ability to turn your head to the left and right (ie. saying “NO”) because of the pivot joint between C1 and C2.

Circumduction is actually a combination of the previous four movements - Flexion, Extension, Abduction and Adduction. So, if a joint can do these four movements, then it can also do Circumduction.

For Example: The Shoulder Joint can perform Flexion, Extension, Abduction and Adduction and can therefore combine these movements to create Circumduction.

For Example: The Shoulder Joint.

For Example: Rotation of the Head/Neck.

External Rotation

Internal Rotation



6.2 Special Movements

As well as the general movements there are a number of Special Movements that the body can perform. They are called special movements because they are only performed in certain parts of the body.

g. Supination

refers to movement of the forearm so the palm faces anteriorly or superiorly.

h. Pronation

refers to movement of the forearm so the palm faces posteriorly or inferiorly.

As you can see from the diagram on the left, the radius (shaded) crosses over the ulna to perform pronation. When returning back to the neutral or anatomical position it is known as supination. What is actually happening is that the radius is rotating on the ulna at the elbow joint, ie. the radio-ulnar joint is a pivot joint therefore enabling rotation to occur. As can be seen from the diagram on the right, a palm up position is supination and palm down pronation.

This movement only occurs in the forearm.



i. Inversion

refers to movement of the foot so the sole is turned medially

j. Eversion

refers to movement of the foot so the sole is turned laterally

Note: In the anatomical position the foot is neither inverted or everted, ie. it is in a neutral position.

k. Plantar Flexion

refers to movement of the ankle so the toe's point inferiorly

l. Dorsiflexion

refers to movement of the ankle so the toe's point superiorly

Note: In the anatomical position the foot is in Dorsiflexion.

Approx. 90% of ankle injuries are inversion injuries where the person rolls over on their ankle, the foot turning inwards/medially.

Inversion Eversion

This movement only occurs at the foot/ankle.

Dorsiflexion occurs when you point your toes up.

Planter Flexion occurs when you point your toes down.

This movement only occurs at the foot/ankle.



m. Protraction

refers to the anterior movement of the mandible/scapula in a transverse plane.

n. Retraction

refers to the posterior movement of the mandible/scapula in a transverse plane.

“Squaring up the Shoulders” involves retracting the scapulas back towards each other.

Propelling or reaching the arm forward involves protracting the scapula.

These two movements only occur at the scapula and mandible.

Projecting the jaw forward is known as protraction.

Returning the jaw backward is known as retraction.



o. Elevation

refers to movement superiorly of the mandible/scapula along a frontal plane.

p. Depression

refers to movement inferiorly of the mandible/scapula along a frontal plane.

Elevation of the scapula is required when attempting to carry something on your shoulders.

Depression of the scapula is to apply a counter-force to your body weight when using crutches.

Drooping the shoulders actually depicts a depressed state and involves depression of the scapula. The opposite is raising the shoulder which requires elevation of the scapula.

These two movements only occur at the scapula and mandible.

Dropping the jaw is known as depression.

Clenching the teeth represents elevation.

Dropping the jaw also typifies a depressed state.



q. Ulnar Deviation

is movement of the hand away from the midline along the frontal plane and towards the ulna side.

r. Radial Deviation

is movement of the hand away from the midline along the frontal plane and towards the radial side.

s. Opposition

refers to contacting of the thumb with the other fingertips on the same hand.

Ulnar Deviation is a deviation of the hand towards the Ulna (ie. little finger side).

Radial Deviation is a deviation of the hand towards the Radius (ie. thumb side).

Note: When referring to movements of the hand, the midline is the imaginary line passing through the middle of the hand

Ulnar deviation may also be referred to as adduction and radial deviation abduction when the reference point becomes the midline of the body.

This movement only refers to the hand and involves the wrist joint.

Midline

Opposition enables us to perform very fine and intricate movements such as threading a needle.



6.3 Additional Movements

t. Gliding

is a back-and-forth and side-to-side movement of one surface over another surface.

u. Lateral Flexion

a sideways movement of the body away from the midline and along the frontal plane (Sideways Bending = Lateral Flexion).

Note:

Lateral Flexion movements occur in relation to the axial skeleton (ie. trunk and head).

When this movement occurs at the appendicular skeleton (ie. limbs) it is known as abduction.

Lateral Flexion of the Head to the left

Lateral Flexion of the Trunk to the left

Midline

Plane joints found at the wrist (Intercarpal joints, ie. between the carpal bones) and the ankle (Intertarsal joints, ie. between the tarsal bones) produce gliding movements.



v. Hyperextension

a movement beyond extension.

Note:

Most joints in the body that can perform Extension can also perform Hyperextension.

Can you think of some joints that cannot go beyond the extended position?

Elbow Knee

Trunk Extension Trunk Hyperextension

Trunk Flexion

Shoulder

Trunk

Head/Neck

Hip

Shoulder Extension

Neck/Head Hyperextension

Shoulder Hyperextension

Hip Hyperextension

Neck/Head Flexion

Hip Flexion

Hip Extension

Shoulder Flexion

Note: Wherever possible talk about a movement in relation to the Joint rather than the Body Part. eg. The terms “Shoulder and Hip Flexion” are used rather than “Arm and Leg Flexion”.



Let’s look at some of the joint movements discussed and apply them to some of the hand movements.

Flexion and Extension of the Wrist occurs at the Radio-Carpal Joint.

Flexion of the Wrist.

Extension of the Wrist.

Flexion and Extension of the Fingers occurs at the Inter-Phalangeal Joints (ie. between the phalanges).

This is the only paired movement that can occur at this joint because it is a Hinge Joint.

Flexion of the Fingers. Extension of the Fingers.

Abduction and Adduction of the fingers occurs at the Knuckle Joint – referred to as the Metacarpo- Phalangeal Joint (ie. between the Metacarpals of the hand and the proximal Phalange.

This joint is a Condyloid Joint. This is why it can do not only flexion/ extension but also abduction/adduction (which equals circumduction).

Abduction of the Fingers. Adduction of the Fingers.

Midline

Midline

Deviation of the Hand occurs at the Wrist, ie. Radio-Carpal Joint.

Which movement is easier to perform - ulnar or radial deviation?

Ulnar Deviation of the Hand (Adduction).

Radial Deviation of the Hand. (Abduction).

Midline Midline



Let’s now expand our thinking to look at a body that is in a different position to the anatomical position. What joint movements have occurred resulting in this change in position?

Anatomical Position

Different Position

Always refer back to the anatomical position to aid your understanding.

1. Trunk Flexion

2. Head Flexion

3. Hip Flexion (Left)

4. Knee Flexion (Left)

5. Foot Planter Flexion (Left)

6. Elbow Flexion (Left)

7. Wrist Flexion (Left)

Note:

The Right Hip has also gone into slight Flexion because of the Trunk Flexion.

Right Knee has remained in Extension. Right Ankle is in Dorsiflexion.

1

7

6

5

4

3

2



7. Characteristics of Body Joints

Let’s summarise what we have covered so far in this subject.

7.1 In Summary

Fibrous Joints

Allow virtually no movement (immoveable). Examples are sutures of the skull and distal tibiofibular joint.

Cartilaginous Joints

Allow only a very small amount of movement (slightly moveable). Examples are the intervertebral discs and the pubic symphysis.

Synovial Joints

Synovial Joints consist of six types of joints, varying from some movement (Plane Joints) through to a wide range of movement (Ball and Socket Joints). Let’s look at this group more closely.

Synovial Joints - Plane

Allow a gliding movement.

Examples are the intercarpal joints which form the wrist and the intertarsal joints which form the ankle and the proximal tibiofibular joint (assists in allowing some twisting of the knee joint).

Note: An exception is the acromioclavicular joint (ie. AC joint at the tip of shoulder) which is a modified plane joint. When the AC joint is used in combination with the sternoclavicular joint (which is a saddle joint) flexion/extension movements occur. The flexion/extension movements at this joint occurs in two different planes and are called elevation/depression and protraction/retraction of the shoulder - however we will discuss this movement in relation to the scapula (ie. elevation/depression and protraction/retraction of the scapula).

Synovial Joints - Hinge

Allow a flexion and extension movement.

Examples are elbow, knee and interphalangeal joints.

Note: The temperomandibular joint (jaw) in a modified hinge joint - the flexion/extension movements at this joint occurs in two different planes and are called elevation/depression and protraction/retraction of the jaw.

Note: The talocrural joint (between the talus and the tibia/fibula) is a hinge joint which permits

an up & down flexion/extension movement known as dorsiflexion/plantarflexion of the foot.



Note: The subtalar joint (between the talus and the calcaneus) is a hinge joint which permits a

sideways flexion and extension movement known as inversion/eversion of the foot.

Synovial Joints - Pivot

Allow a rotation movement.

Examples are the atlantoaxial joint of the neck (between C1 and C2) and the proximal radioulnar joint (at the elbow enabling pronation/supination of the forearm).

Synovial Joints - Condyloid

Allows flexion and extension and also abduction and adduction (plus circumduction since this movement is a combination of the previous four movements).

Examples are the metacarpophalangeal joint (knuckles) and the radiocarpal joint (wrist).

Synovial Joints - Saddle

Allows the same movements as given for the Condyloid, however a greater range is permitted due to its slightly different structure.

Examples are the carpometacarpal joint (1st digit), ie. the base of the thumb and the sternoclavicular joint (modified arrangement).

Note: Some text books indicate the thumb as being the only saddle joint in the body.

Synovial Joints - Ball and Socket

Allows all six general movements of the body - flexion and extension, abduction and adduction, circumduction and finally rotation.

There are only two Ball and Socket joints in the body - the shoulder and the hip.



Using your manual and any other learning resources that you may have available, complete the

following table.

Note: Ignore the functional joint terms used, ie. diathrotic, synarthrotic, etc.

Joint

Articulating bones

Type of joint

Movements allowed

1 Skull cranial and facial bones

2 Temporomandibular synovial - hinge joint (modified)

3 Atlanto-occipital flexion/extension lateral flexion circumduction

4 Atlantoaxial between the atlas and axis

5 Intervertebral between adjacent vertebral bodies

6 Vertebrocostal between vertebrae and ribs

7 Sternoclavicular synovial - saddle (shallow)

8 Sternocostal gliding

9 Acromioclavicular acromion process of scapula and clavicle

10 Glenohumeral (Shoulder)

synovial - ball and socket

11 Elbow ulna and radius with humerus

12 Radioulnar (proximal)

rotation to allow pronation and supination

13 Wrist (Radiocarpal)

synovial - condyloid

14 Intercarpal adjacent carpals

15 Base of thumb (carpometacarpal of digit 1)

synovial - saddle

16 Knuckle (metacarpophalangeal)

synovial - condyloid



Joint

Articulating bones

Type of joint

Movements allowed

17 Finger (interphalangeal)

flexion/extension

18 Sacroiliac sacrum and coxal bone

19 Pubic symphysis cartilaginous

20 Hip (coxal)

flexion/extension abduction/adduction circumduction rotation

21 Knee (tibiofemoral)

synovial - hinge

22 Ankle (talocrural)

tibia and fibula with talus

23 Ankle (subtalar)

talus and calcaneus

24 Intertarsal gliding

25 Tarsometatarsal synovial - plane

26 Metatarso- phalangeal

metatarsal and proximal phalanx

27 Toe (interphalangeal)

flexion/extension



The Muscular System

8. Introduction to Skeletal Muscle

8.1 Basic Structure of Skeletal Muscle

1. Belly

constitutes the bulk of the muscle

2. Attachments

the ends of a muscle consisting of connective tissue (tendon) attachments consist of the ORIGIN and INSERTION

ORIGIN

the fixed attachment and is usually the proximal end

this end does not move during muscle contraction

INSERTION

the moveable attachment and is usually distal end

this end is the end that moves during muscle

contraction

3. Fascia

the layer of fibrous tissue covering and protecting the muscle

4. Tendon

the cord of dense fibrous tissue which attaches the muscle to bone

Introduction to

Skeletal Muscles

9. Major Muscles of

The structure of skeletal muscle as shown enables it to produce forceful contractions.

This is one of the major functional distinctions between skeletal muscle and other muscle tissue types (ie. cardiac and smooth muscle).

1

3

4

2 - Insertion

2 - Origin



8.2 Types of Skeletal Muscle

There are four main types of skeletal muscle based on the patterns resulting from the arrangement of fibres.

1. Parallel

the long axis of the muscle fibres run with the longitudinal axis of the muscle and the muscle is either straplike or fusiform.

2. Pennate

the muscle fibres are short and are attached obliquely to a central tendon running the length of the muscle.

3. Convergent

the muscle has a broad origin and its fibres converge towards a single tendon.

4. Circular

the muscle fibres arrange to form a circle and the muscle is always found around external openings to control opening/closing.

8.3 Types of Muscle Attachments

Muscles are attached to bone (or other structures) directly or indirectly.

1. Direct Attachment

the fascia of the muscle attaches to the bone or cartilage.

2. Indirect Attachment

the fascia extends beyond the muscle as a tendon (ropelike) or an aponeurosis (flat, broad), anchoring the muscle to bone, cartilage or fascia of other muscles. Most muscles attach indirectly.

8.4 Integration of Muscle Action

A muscle will be in one of three states:

Contracted: muscle shortens and a joint is moved with the two bones coming closer together

Relaxed: muscle is in neutral, ie. at rest

Stretched: muscle lengthened due to opposing muscle contraction



8.5 The Role of Muscles in Movement

Muscles can’t push, they can only pull as they contract, so most

often body movements are the result of the activity of pairs or

teams of muscles acting together or against each other. Muscles

are arranged on the skeleton in such a way that whatever one

muscle (or group of muscles) can do, another group of muscles

can reverse. Because of this, muscles are able to bring about an

immense variety of movements. A muscle can be termed one of

the following depending on its role within a particular movement:

1. Prime Mover (Agonist)

the primary muscle effecting a desired joint movement When several muscles are contracting at the same time, the muscle that has the major responsibility for causing a particular movement is called the prime mover (this physiologic term has been borrowed by the business world to label a person who gets things done).

2. Antagonist

the muscle which opposes a certain movement Muscles that oppose or reverse a movement are antagonists. When a prime mover is active, its antagonist is stretched and relaxed.

3. Fixator

a muscle that stabilises a joint during movement Fixators are specialized synergists. They act to hold a bone still or to stabilize the origin of a prime mover so all the tension can be used to move the insertion bone. The postural muscles stabilising the vertebral column are fixators, as are the muscles anchoring the scapula to the thorax.

4. Synergist

a muscle which assists in performing the desired joint movement Synergists are muscles that help prime movers by producing the same movement, or by reducing undesirable or unnecessary movement. When a muscle crosses two or more joints, its contraction will cause movement in all joints crossed unless synergists are there to stabilize them. For example, the finger flexor muscles cross both the wrist and the finger joints. You can make a fist without bending your wrist because synergist muscle stabilize the wrist joints and allow the prime mover to act on the finger joint.

In summary, although prime movers seem to ‘get all the credit’ for causing certain movements, the actions of antagonists and synergists muscles are also important in effecting smooth, co-ordinated and precise movements.

MUSCLES

PULL THEY DON’T

PUSH.

This is an important concept when learning about muscular action in the body.

Antagonists can be prime movers in their own right.

For example, the biceps of the arm (prime mover of elbow flexion) is antagonized by the triceps (a prime mover of the elbow extension).



8.6 Types of Muscle Contractions

There is actually three types of ways a muscle can contract to produce force. In each case the muscle is pulling on one bone in relation to another bone in an attempt to move the joint that the muscle has crossed.

Remember that the movement created could be any of the joint movements already discussed, e.g. flexion/extension, abduction/adduction, etc.

1. Concentric Contraction

this is a muscle contraction where the muscle shortens during contraction.

this is the common type of contraction that we are all familiar with and has been previously demonstrated in the diagram shown earlier.

an example of this is doing elbow flexion with a weight in your hand - this would involve the biceps performing a concentric contraction (refer to earlier diagram)

2. Eccentric Contraction

this is a muscle contraction where the muscle actually lengthens during contraction.

to understand how this is possible you need to remind yourself that muscles pull they don’t push.

an example of this is doing elbow extension with a weight in your hand - this would involve the biceps performing an eccentric contraction (refer to earlier diagram and imagine a weight being lowered by the arm); being able to guide the weight down carefully would involve the biceps lengthening but having to also contract.

3. Isometric Contraction

this is a muscle contraction where the muscle actually remains the same length during contraction.

using the example of the weight in your hand - an isometric contraction of the biceps would occur if you were to simply hold the weight in a stationary position; you know you are still contracting the biceps because after a period of time your muscle begins to tire.



8.7 Naming Skeletal Muscles

To help in your learning of the major muscles in the body it is valuable to understand that many of the muscles are named according to a number of criteria. Each criteria focuses on a particular structural or functional characteristic of the muscle.

1. Location of the muscle

Some muscle names indicate the bone or body region with which the muscle is associated,.eg. intercostal muscles – inter (between) costal (ribs)

2. Shape of the muscle

Some muscles have a distinctive shape,. eg. deltoid (triangle),trapezius (trapezium/diamond)

3. Relative size of the muscle

Individual muscles within some muscle groups are defined according to their relative size, eg. gluteus maximus (large), medius (medium) & minimus (small) or peroneus longus (long) & brevis (short)

4. Direction of muscle fibres

Some muscles are named according to the direction of their muscles fibres. The direction is in reference to an imaginary line which is usually the midline of the body or the longitudinal axis., eg. rectus (straight) abdominis & transverse (transverse/ diagonal) abdominis or external (outside) oblique and internal (inside) oblique

5. Number of origins

Part of the muscle’s name can indicate the number of origins (or heads) that particular muscle has, eg. biceps (2 heads) brachii, triceps (3 heads) brachii, quadriceps (4 heads)

6. Location of the muscle’s origin and/or insertion

Some muscles are named according to where they attach, e.g. sternocleidomastoid - sterno (sternum) cleido (clavicle) mastoid (mastoid process of skull)

7. Action of the muscle

An action word may be part of the muscle name, indicating the main action the muscle is involved in, e.g. adductor longus – performs adduction

Note: Often several of the above criteria are combined in the naming a muscle.eg. extensor carpi radialis longus



9. Major Muscles of the Body

9.1 Muscles of the Upper Back

Trapezius (Upper, Middle & Lower) Rhomboids Levator Scapulae

9.2 Muscles of the Neck

Sternocleidomastoid Scalenes (Anterior, Middle & Posterior) Splenius Capitus

9.3 Muscles of the Shoulder

Deltoid Rotator Cuff: Supraspinatus, Infraspinatus, Teres Minor, Subscapularis Teres Major

9.4 Muscles of the Arm

Biceps Brachii Triceps Brachii Brachialis Brachioradialis Coracobrachialis Forearm Flexors & Extensors

9.5 Muscles of the Chest

Pectorals: Pectoralis Major (Clavicular & Sternal), Pectoralis Minor Serratus Anterior Diaphragm Intercostals: External & Internal

9.6 Muscles of the Abdomen

Abdominals: Rectus Abdominis, External Oblique, Internal Oblique, Transverse Abdominis

Iliopsoas

9.7 Muscles of the Lower Back

Latissimus Dorsi



Erector Spinae Quadratus Lumborum

9.8 Muscles of the Buttocks

Gluteals: Gluteus Maximus, Gluteus Medius, Gluteus Minimus Piriformis

9.9 Muscles of the Posterior & Lateral Leg

Hamstrings: Biceps Femoris, Semitendionosus, Semimembranosus Tensor Fascia Latae Gastrocnemius Soleus Peroneus

9.10 Muscles of the Anterior & Medial Leg

Quadriceps: Rectus Femoris, Vastus Lateralis, Vastus Medialis & Vastus Intermedius Sartorius Adductors (Magnus, Longus & Brevis) Pectineus Gracilis Tibialis Anterior



The major muscles of the body will now be examined in some detail. Below is a discussion of the format used to help you in your studies.

Biceps Brachii The biceps brachii is the most familiar muscle of the forearm because it bulges when the elbow is flexed. It originates by two heads from the shoulder girdle and inserts into the radial tuberosity. This muscle is the powerful prime mover for flexion of the forearm and acts to supinate the forearm. The best way to remember its action is that it ‘turns the corkscrew and pulls the cork’.

Looking at the above information you will be able to get a grasp of the movements an individual muscle is responsible for in the body. In the case of Biceps Brachii shown above, when the Moveable End (Insertion) moves closer to the Fixed End (Origin) during a Concentric Contraction (ie. shortening of the muscle), one of the movements resulting is FLEXION of the ELBOW.

PLEASE NOTE: In working out a muscle’s action you must consider 2 things: 1. Muscles only pull they don’t push (so refer to point 3 and imagine the insertion being pulled

closer to the origin). 2. Always visualise the action based on the muscle shortening, ie. the resultant action is based on a

concentric contraction.

9. The fixed attachment of the muscle. 8. The moveable attachment of the muscle. 7. The movements that the muscle can perform. PM = Prime Mover

Origin

Supraglenoid tubercle of scapula (long head) Coracoid process of scapula (short head)

Insertion

Radial/Bicipital tuberosity of radius

Action

Shoulder: Flexion Elbow: FlexionPM Forearm: Supination

1. Name of Muscle

2. A brief description of Muscle

3. Attachments connected by a line to help show the “line of pull” of the muscle – the muscle action can therefore be understood.

4. Attachments marked on the bones, ie. origin and insertion.

6. The superficial part of the muscle is highlighted. If this diagram is not shown then there is no superficial aspect to the muscle, ie. the entire muscle is deep to other superficial muscles.

5. The entire muscle is shown here on the body. Please note that this is not a superficial view as shown in point 6. Refer to this in conjunction with points 3 & 4.



9.1 Muscles of the Upper Back

Trapezius

The trapezius muscles are the most superficial muscles of the posterior neck and upper trunk. When seen together, they form a diamond or kite shaped muscle mass. Their origin is very broad; each runs from the occipital bone of the skull down the vertebral column to the end of the thoracic vertebrae. They then flare laterally to insert on the scapular spine and clavicle. The trapezius muscles extend the head (thus are antagonists of the sternocleidomastoid. They also can elevate, depress, retract and stabilize the scapula.

Origin Occipital bone Nuchal Ligament C1- C7 Spinous Processes C7 - T12

Insertion Spine of Scapula Acromion Process of Scapula Lateral 1/3rd of Clavicle (continuous insertion - big V)

Action Scapula: Depression (Lower Fibres) Retraction (Middle Fibres) Elevation (Upper Fibres) Rotation Head: Extension PM



Rhomboids

A rectangular muscle lying deep to the trapezius between the scapula and the vertebral column.

Origin Spinous processes C7 - T5

Insertion Medial border of scapula - from inferior angle to spine of scapula

Action Scapula: Elevation Retraction



Levator Scapulae

A straplike muscle located deep to the trapezius at the back of the neck. Commonly associated with muscular tension of the posterior neck, particularly when rotation is involved.

Origin Transverse processes C1 - C4

Insertion Medial border of scapula from superior angle to the spine of sapula

Action Scapula: Elevation Head: Lateral flexion Rotation



9.2 Muscles of the Neck

Sternocleidomastoid

The paired sternocleidomastoid muscles are two headed muscles, one found on each side of the neck. Of the two heads of each muscle, one arises from the sternum and the other arises from the clavicle. The heads fuse before inserting into the mastoid process of the temporal bone. When both sternocleidomastoid muscles contract together, they flex your neck. (It is this action of bowing the head that has led some people to call these muscles the “prayer” muscles.) If just one muscle contracts, the head is rotated toward the opposite side. In some difficult births, one of these muscles may be injured and develop spasms. A baby injured in this way has torticollis or wryneck.

Origin Manubrium of sternum Medial 1/3rd of clavicle

Insertion Mastoid process of temporal bone

Action Head: Flexion (both) PM Lateral flexion (one) - to same side rotation (one) - to opposite side



Scalenes

A group of three muscles (anterior, middle and posterior) located more laterally than anteriorly on the neck and deep to the sternocleidomastoid.

Origin Transverse processes of cervical vertebrae

Insertion Ribs 1 and 2

Action Ribs: Elevation Neck: Flexion, Rotation



Splenius Capitus

Known as the “bandage muscle” because it covers and holds down deeper posterior neck muscles. Lies beneath the upper trapezius.

Origin Nuchal Ligament Spinous processes of upper thoracic vertebrae Insertion Mastoid process of temporal bone

Action Head: Extension Lateral Flexion



9.3 Muscles of the Shoulder

Deltoid (Anterior, Middle & Posterior)

The deltoids are fleshy, triangle shaped muscles that form the rounded shape of your shoulders. Because they are so bulky, they are a favorite injection site when relatively small amounts of medication (less than 5ml) must be given intramuscularly (into muscle). The origin of each deltoid winds across the shoulder girdle from the spine of the scapula to the clavicle. It inserts into the proximal humerus. The deltoids are the prime movers of the arm abduction.

Origin Spine of scapula Acromion process of scapula Lateral 1/3rd of clavicle (continuous insertion - big V)

Insertion Deltoid tuberosity of humerus

Action Shoulder: Flexion (Anterior) PM Medial Rotation (Anterior) Abduction (Middle) PM Extension (Posterior) PM Lateral rotation (Posterior)





Rotator Cuff Muscles

The shoulder joint allows a large range of mobility at the expense of stability. Four muscles known as Rotator Cuff muscles are responsible for pulling the humeral head into the scapular socket during shoulder movements. The musculotendinous (“rotator”) cuff created by these muscles enables the prime movers of the shoulder (pectoralis major, deltoid and latissimus dorsi) to do their work.

Rotator Cuff - Supraspinatus

Important muscle in stabilising the shoulder joint located on the posterior aspect of the scapula deep to the trapezius.

Origin Supraspinous fossa of scapula

Insertion Greater tubercle of humerus -superior aspect

Action Shoulder: Abduction

Note: muscle runs under acromion process.



Rotator Cuff - Infraspinatus

Helps to hold the head of the humerus in the glenoid cavity, partially covered by the deltoid and trapezius.

Origin Infraspinous fossa of scapula

Insertion Greater tubercle of humerus - middle aspect

Action Shoulder: Lateral rotation PM



Rotator Cuff - Teres Minor

A small, elongated muscle lying inferior to infraspinatus and may appear inseparable from that muscle.

Origin Lateral border of scapula - upper 2/3rd

Insertion Greater tubercle of humerus - inferior aspect

Action Shoulder: Lateral Rotation PM



Rotator Cuff - Subscapularis

Forms part of posterior wall of axilla and located on anterior surface of scapula.

Origin Subscapular fossa of scapula

Insertion Lesser tubercle of humerus

Action Shoulder: Medial rotation PM



Teres Major

Thick, round muscle located inferior to Teres Minor and also helps form posterior wall of axilla.

Origin Lateral border of scapula - lower 1/3rd

Insertion Intertubercular groove of humerus

Action Shoulder: Adduction Extension Medial Rotation



9.4 Muscles of the Arm

Biceps Brachii

The biceps brachii is the most familiar muscle of the forearm because it bulges when the elbow is flexed. It originates by two heads from the shoulder girdle and inserts into the radial tuberosity. This muscle is the powerful prime mover for flexion of the forearm and acts to supinate the forearm. The best way to remember its action is that ‘it turns the corkscrew and pulls the cork’.

Origin Supraglenoid tubercle of scapula (long head) Coracoid process of scapula (short head)

Insertion Radial/Bicipital tuberosity of radius

Action Shoulder: Flexion Elbow: Flexion PM Forearm: Supination



Triceps Brachii

The triceps muscle is the only muscle fleshing out the posterior humerus. Its three heads arise from the shoulder girdle and proximal humerus and it inserts into the olecranon process of the ulna. Being the powerful prime mover of elbow extension, it is the antagonist of the biceps brachii.

Origin Infraglenoid tubercle of scapula (long head) Posterior aspect of humerus (lateral and medial head)

Insertion Olecranon process of ulna

Action Shoulder: Adduction Extension Elbow: Extension PM

Long

Medial

Lateral



Brachialis

Strong muscle deep to biceps brachii on distal humerus.

Origin Distal 1/2 of anterior humerus

Insertion Coronoid process of ulna

Action Elbow: Flexion PM



Brachioradialis

Prominent muscle of the lateral forearm.

Origin Lateral aspect of distal humerus (supracondylar ridge)

Insertion Styloid process of radius

Action Elbow: Flexion



Coracobrachialis

Small, cylindrical muscle located underneath Deltoid and Pectoralis Major.

Origin Coracoid process of scapula

Insertion Medial aspect of humerus

Action Shoulder: Flexion Adduction



Forearm Flexors

Group of muscles on the anterior forearm.

Origin Medial epicondyle of humerus

Insertion Carpals, metacarpals and phalanges - anterior aspect

Action Wrist: Flexion PM Fingers: Flexion PM



Forearm Extensors

Group of muscles on the posterior forearm.

Origin Lateral epicondyle of humerus

Insertion Carpals, metacarpals and phalanges - posterior aspect

Action Wrist: Extension PM Fingers: Extension PM



9.5 Muscles of the Chest

Pectorals: Pectoralis Major (Clavicular and Sternal)

The pectoralis major is a large fan-shaped muscle covering the upper part of the chest. Its origin is from the shoulder girdle and the first six ribs. It inserts in the proximal end of the humerus. This muscle forms the anterior wall of the axilla and acts to adduct and flex the arm.

Origin Medial 2/3rd of clavicle Sternum Ribs 1-6


Action Shoulder: Flexion PM Adduction PM Medial rotation

Clavicular Fibres

Sternal Fibres



Pectorals: Pectoralis Minor

A flat, thin muscle directly beneath and obscured by the Pectoralis Major.

Origin Ribs - 3, 4 and 5 - anterior surface

Insertion Coracoid process of scapula

Action Scapula: Protraction Depression Ribs: Elevation (Inspiration)



Serratus Anterior

Lies deep to the scapula and inferior to the pectoral muscles on the lateral rib cage. The last section of the muscle on the lateral aspect is superficial. Referred to as the boxer’s muscle due to its ability to protract the humerus (scapula) as is required when a boxer propels his arm forward when executing a punch.

Origin Ribs - 1- 8, anteriolaterally

Insertion Medial border of scapula

Action Scapula: Protraction Rotation



Diaphragm

A broad muscle forming the floor of the thoracic cavity and is the primary muscle involved in respiration.

Intercostals: External & Internal

The intercostal muscles are deep muscles found between the ribs. The external intercostals are important in breathing because they help to raise the rib cage for breathing air in. The internal intercostals depress the rib cage, which helps to move air out of the lungs when you exhale forcibly.

Origin Inside rim of ribs

Insertion Central tendon

Action Respiration

Origin Inferior border of rib above

Insertion Superior border of rib below

Action Inspiration

Refer to comments on Video clips.

External Intercostals

Origin Superior border of rib below

Insertion Inferior border of rib above

Action Expiration (forced)

Refer to comments on Video clips.

Internal Intercostals



9.6 Muscles of the Abdomen

Abdominals: Rectus abdominis

The paired straplike rectus abdominis muscles are the most superficial muscles of the abdomen. They run from the pubis to the rib cage, enclosed in an aponeurosis. Their main function is to flex the vertebral column. They also compress the abdominal contents during defecation and childbirth and are involved in forced breathing.

Origin Pubic bone

Insertion Xiphoid process Ribs 5, 6 and 7

Action Trunk: Flexion



Abdominals: External Oblique

The external oblique muscles are paired superficial muscles that make up the lateral walls of the abdomen. Their fibres run downward and medially from the last eight ribs and insert into the ilium. Like the rectus abdominis, they flex the vertebral column but they also rotate the trunk and bend it laterally.

Origin Lower 8 ribs

Insertion Linea Alba via abdominal aponeurosis

Action Trunk: Flexion Rotation



Abdominals: Internal Oblique

The internal oblique muscles are paired muscles deep to the external obliques. Their fibres run at right angles to those of the external obliques. They arise from the iliac crest and insert into the last three ribs. Their functions are the same as those of the external obliques.

Abdominals: Transverse Abdominis

The transverse abdominis is the deepest muscle of the abdominal wall and has fibres that run horizontally across the abdomen. It arises from the lower ribs and iliac crest and inserts into the pubis. This muscle compresses the abdominal contents.

Origin Thoraco-lumbar fascia iliac crest


Action Trunk: Flexion Rotation

Refer to comments on video clips.

Refer to comments on video clips.

Origin Thoraco-lumbar fascia iliac crest


Action Trunk: Acts as a girdle



Iliopsoas

A composite of two closely related muscles (iliacus and psoas major) whose fibres run under the inguinal ligament. An important flexor of the hip.

Origin Iliacus - iliac fossa Psoas - lumbar vertebral bodies, anterior surface

Insertion Lesser trochanter of femur

Action Hip: Flexion PM



9.7 Muscles of the Lower Back

Latissimus Dorsi

The latissimus dorsi is the large, flat muscle pair that covers the lower back. It originates on the lower spine and ilium and then sweeps superiorly to insert into the proximal end of the humerus. These are very important muscles when the arm must be brought down in a power stroke, as when swimming or striking a blow, hence referred to as the ‘swimmer’s muscle’.

Origin Spinous processes T6 - T12 Lumbar vertebrae, sacrum and iliac crest via thoraco-lumbar fascia


Action Shoulder: Extension PM Adduction PM Medial Rotation



Erector Spinae

The erector spinae is a prime mover of back extension. Because these paired muscles are deep muscles of the back. Each erector spinae is a composite muscle consisting of three muscle columns (Spinalis, Longissimus and Iliocostalis) that collectively span the entire length of the vertebral column. These muscles not only act as powerful back extensors ('‘erectors'’), but they provide resistance that helps control the action of bending over at the waist. Following injury to back structures, these muscles go into spasms, a common source of lower back pain.

Origin Many and varied

Insertion Many and varied

Action Trunk: Extension

1. Spinalis 2. Longissimus 3. Iliocostalis

1 2 3



2

1

3

P a g e | 1 0 0 E V O L V E C O L L E G E


Quadratus Lumborum

A fleshy muscle found in the lumbar region deep to the erector spinae and extremely important in stabilising and supporting the lower back.

Origin Iliac crest

Insertion Transverse processes L1 - L5 12th Rib

Action Trunk: Lateral Flexion

E V O L V E C O L L E G E P a g e | 1 0 1


9.8 Muscles of the Buttock

Gluteals: Gluteus maximus

The gluteus maximus is a superficial muscle of the hip that forms most of the flesh of the buttock. It is a powerful hip extensor that acts to bring the thigh in a straight line with the pelvis. Although not very important in walking, it is probably the most important muscle for extending the hip when power is needed, as when climbing stairs and when jumping. It originates from the sacrum and iliac bones and runs to insert to the gluteal tuberosity of the femur.

Origin Iliac crest of pelvis Sacrum Coccyx

Insertion Gluteal tuberosity of femur Lateral condyle of tibia via iliotibial band

Action Hip: Extension PM lateral rotation



Gluteals: Gluteus medius

The gluteus medius runs from the ilium to the femur, beneath the gluteus maximus for most of its length. The gluteus medius is a hip abductor and is important in steadying the pelvis during walking. The gluteus medius is an important site for giving intramuscular injections, particularly when more than 5ml is administered. Although it might appear that the large, fleshy gluteus maximus that forms the bulk of the buttock mass would be a better choice, notice that the medial part of each buttock overlies the large sciatic nerve; hence this area must be carefully avoided. This can be accomplished by mentally dividing the buttock into four equal quadrants. The upper outer quadrant then overlies the gluteus medius muscle, which is usually a very safe site for an intramuscular injection.

Origin Ilium

Insertion Greater trochanter of femur

Action Hip: Abduction PM Medial rotation



Gluteals: Gluteus minimis

The smallest and deepest of the gluteal muscles.

Origin Ilium

Insertion Greater trochanter of femur

Action Hip: Abduction Medial rotation



Piriformis

A pyramidal muscle located deep to the gluteals and opposite the greater sciatic notch. Often associated with sciatic nerve problems due to being in close proximity to this nerve. In a small percentage of people the nerve actually innervates this muscle, such clients are particularly susceptible to sciatic pain if muscle tension exists in this region of the body.

Origin Sacrum (opposite greater sciatic notch)

Insertion Greater trochanter of femur - superior aspect

Action Hip: Abduction Lateral rotation



9.9 Muscle of the Posterior & Lateral Leg

Hamstrings: Biceps femoris

The muscles forming the muscle mass of the posterior thigh are the hamstrings. The group consists of three muscles: the biceps femoris, semimembranosus and semitendinosus, which originate on the ischial tuberosity and run down the thigh to insert on both sides of the proximal tibia. Their name comes form the fact that butchers use their tendons to hang ‘hams’ (consisting of thigh and hip muscles) for smoking. These tendons can be felt at the back of the knee.

Origin Ischial tuberosity of pelvis (long head) posterior aspect of femur (short head)

Insertion Lateral condyle of tibia Head of fibula

Action Hip: Extension PM Knee: Flexion PM

Long Head

Short Head



Hamstrings: Semitendinosus

The muscles forming the muscle mass of the posterior thigh are the hamstrings. The group consists of three muscles: the biceps femoris, Semimembranosus and Semitendinosus, which originate on the ischial tuberosity and run down the thigh to insert on both sides of the proximal tibia. Their name comes from the fact that butchers use their tendons to hang ‘hams’ (consisting of thigh and hip muscles) for smoking. These tendons can be felt at the back of the knee.

Origin Ischial tuberosity of pelvis

Insertion Medial condyle of tibia




Hamstrings: Semimembranosus

The muscles forming the muscle mass of the posterior thigh are the hamstrings. The group consists of three muscles: the biceps femoris, Semimembranosus and Semitendinosus, which originate on the ischial tuberosity and run down the thigh to insert on both sides of the proximal tibia. Their name comes from the fact that butchers use their tendons to hang ‘hams’ (consisting of thigh and hip muscles) for smoking. These tendons can be felt at the back of the knee.

Origin Ischial tuberosity of pelvis

Insertion Medial condyle of tibia




Tensor Fascia Latae

A small bulky muscle on the proximal anterolateral aspect of the thigh which runs into the iliotibial tract laterally as a tendinous band to the knee. The TFL muscle has been placed in this section of the notes due to the lateral location of its tendon. However, it could more accurately be described as being anterior muscle due to muscle itself being predominantly located on the anterior aspect of the thigh.

Origin ASIS of pelvis

Insertion Lateral condyle of tibia via iliotibial band

Action Hip: Flexion Abduction Medial rotation



Gastrocnemius

The gastrocnemius muscle is a two bellied muscle that forms the curved calf of the posterior leg. It arises by two heads, one from each side of the distal femur and inserts through the large Achilles (calcaneal) tendon into the heel of the foot. It is a prime mover for plantar flexion of the foot; for this reason it is often called the ‘toe dancer’s’ muscle. If its insertion tendon is cut, walking is very difficult. The foot drags because the heel cannot be lifted.

Origin Condyles of femur (ie. femoryl condyles)

Insertion Calcaneus via achilles tendon

Action Knee: Flexion Ankle/Foot: Plantar flexion PM



Soleus

Deep to the gastrocnemius and is also important in plantarflexion of the foot.

Origin Posterior aspect of tibia and fibula

Insertion Calcaneus via achilles tendon

Action Ankle/Foot: Plantarflexion PM



Peroneus

The three peroneus muscles of this group are found on the lateral part of the leg. They arise from the fibula and insert into the metatarsal bones of the foot. The group as a whole plantar flexes and everts the foot.

tendon continues underneath foot

inserts on underside of foot at site of 1st cuniform & 1st metatarsal

Origin Head and upper portion of fibula

Insertion Medial foot - posterior aspect

Action Ankle/Foot: Plantarflexion Eversion



9.10 Muscles of the Anterior and Medial Leg

Quadriceps: Rectus Femoris

The quadriceps group consists of four muscles – the rectus femoris and three vastus muscles – which flesh out the anterior thigh. The vastus muscles originate from the femur; the rectus femoris originates on the pelvis. All four muscles insert into the tibial tuberosity by the patellar tendon. The group as a whole acts to extend the knee powerfully, as when kicking a football. Because the rectus femoris crosses two joints, the hip and the knee, it can also help to flex the hip. The lateral vastus and rectus femoris are sometimes used as intramuscular injection sites, particularly in infants, who have poorly developed gluteus muscles.

Origin AIIS of pelvis

Insertion Tibial tuberosity via patellar tendon

Action Hip: Flexion Knee: Extension PM



Quadriceps: Vastus Medialis (1)

Vastus Lateralis (2)

Vastus Intermedius (3)

The quadriceps group consists of four muscles – the rectus femoris and three vastus muscles – which flesh out the anterior thigh. The vastus muscles originate from the femur; the rectus femoris originates on the pelvis. All four muscles insert into the tibial tuberosity by the patellar tendon. The group as a whole acts to extend the knee powerfully, as when kicking a football. Because the rectus femoris crosses two joints, the hip and the knee, it can also help to flex the hip. The lateral vastus and rectus femoris are sometimes used as intramuscular injection sites, particularly in infants, who have poorly developed gluteus muscles.

Origin Anterior aspect of femur

Insertion Tibial tuberosity via patellar tendon

Action Knee: Extension PM

1 2

3



Sartorius

Compared to other thigh muscles, described here, the thin, straplike sartorius muscle is not too important; but since it is the most superficial muscle of the thigh it is rather hard to miss. It runs obliquely across the thigh from the anterior iliac crest to the medial side of the tibia. It is a weak thigh flexor. The sartorius is commonly referred to as the ‘tailors’ muscle because it acts as a synergist to bring about the cross-legged position in which old time tailors are often shown.

Origin ASIS of pelvis

Insertion Medial condyle of tibia (pes anserine)

Action Hip: Flexion Abduction Lateral rotation Knee: Flexion (ie. cross leg position)



Adductors: Adductor Brevis (1)

Adductor Longus (2)

Adductor Magnus (3)

Large muscle mass consisting of three muscles forming the medial aspect of the thigh. Strain or stretching of this muscle group is called a “pulled groin”.

Origin Pubic bone

Insertion Linea Aspera of femur

Action Hip: Adduction PM Lateral Rotation

1

2 3

2

3

1



Pectineus

A short, flat muscle overlying the adductors on the proximal thigh.

Origin Pubic bone

Insertion Linea Aspera of femur

Action Hip: Adduction



Gracilis

A long, thin superficial muscle running the full length of the medial thigh.

Origin Pubic bone

Insertion Medial condyle of tibia (pes anserine)

Action Hip: Adduction



Tibialis Anterior

Superficial muscle of the anterior leg parallels laterally the sharp anterior margin of the tibia.

Origin Lateral condyle and upper 2/3rd of tibia

Insertion Medial foot - anterior aspect

Action Ankle/foot: Dorsiflexion PM Inversion



Overview

This subject will assist you in getting an overview of Musculoskeletal Anatomy.

Rather than examining each individual section in isolation (as is done with the multiple choice questions), this overview attempts to bring the information together for you by examining muscles in groups and reviewing their actions.

To effectively study this section you will need to have a good understanding of Musculoskeletal Anatomy - The Skeletal System, The Articular System and The Muscular System.

10. Review

Having read the content of this manual and completed all the multiple choice questions, you may then wish to review the entire subject again. You may find that you see some of the course content in a different light and gain a greater understanding of Musculoskeletal Anatomy.

Let’s begin by reviewing Musculoskeletal Anatomy - The Skeletal System.

10.1 The Skeletal System

Keep in mind that the bones within the skeletal system are classified according to their shape and not their size. So a long bone, consisting of a shaft and two ends, can be found within your fingers (phalanges) and also found within your thigh (femur). Regardless of size, it is the shape that is important. In these examples, they both have a shaft and two ends. Whereas with a short bone, if you actually remove the shaft and bring the two ends together, you essentially get a roughly cube-like shape. A good example is the bones within the wrist (carpals). A flat bone, referring to the bone being thin and flattened, are bones like those found within the skull (ie. parietal and frontal bones). An irregular bone is any bone that doesn’t fit into one of the other three categories - so they are not a long bone, short bone or a flat bone; hence you have the term irregular bone. As the term would suggest, they are usually fairly odd in their shape. Perhaps the most immediate example that comes to mind is the vertebrae.

With regard to the skeleton, it can be broken up into appendicular and axial skeleton. Keep in mind that the appendicular skeleton is primarily involved in movement, hence you are talking about the limbs and also the girdles which are attached to the limbs - so you have the upper limb with the shoulder girdle and you have the lower limb with the pelvic girdle. The girdles certainly have a role to play in encouraging movement by the attached limbs. The axial skeleton on the other hand is the part of the skeleton which revolves around the vertical axis of the body hence the term axial skeleton. Given its position within the skeletal structure of the body you can understand that it is primarily involved in protection. We have involved here the skull, the thorax and the vertebral column.

Let’s now look at, just briefly, the bones found in each of these two categories.



Axial Skeleton

Let’s start by looking at the axial skeleton and firstly the skull bones.

The skull can be primarily be broken up into two sections: cranial bones and facial bones. The cranial bones consist of the frontal bone, parietal bones, temporal bones, occipital bone, sphenoid bone and ethmoid bone. With regard to your learning, it is particularly important that you know where the frontal, parietal, temporal and occipital bones are. Due to their location, they are the most relevant to the massage therapist. The second category, facial bones, consist of the maxilla, palatine bones, zygomatic bones, lacrimal bones, nasal bones, inferior nasal concha, vomer and mandible. Keep in mind that as a massage therapist, the important bones here are the maxilla which is the upper jaw; the zygomatic which is the cheek; the nasal bone, which is of course, the nose; and the mandible, which is the lower jaw. You had an activity in your part 1 manual which involved you colouring in the parts of the skull. It’s a good idea to complete this activity if you haven’t already done so.

If we move on to the vertebral column and vertebrae you see there in your manual a side on (lateral) view of the vertebral column. Notice the curvature changes as you go into each region of the vertebral column.

So we start with the cervical vertebrae and in particular it is important to note that the first two are special cervical vertebrae hence they have individual names, the atlas, think of the Greek God Atlas who held the world on his shoulders and hence you have this vertebrae (the atlas holds the head upon the vertebral column). The second vertebrae is the axis and it is called the axis because it has a little bony protrusion going up vertically which penetrates into the atlas and as a result the joint between these two bones is able to rotate. These two vertebrae represent C1 & C2, the remaining cervical vertebrae make up C3 - C7. The slight forward curvature of the neck encompasses these seven vertebrae. As you can appreciate, these small vertebrae of the neck have a crucial role to play in the integrity of the head and neck musculature. Their alignment is important given that they are the link between the head and the thoracic vertebrae below which have the luxury of being connected to the thorax. The complexity of the musculature around the neck region provides the necessary reinforcement to an otherwise potentially vulnerable area of the body. Palpation along the posterior neck confirms this as it is difficult to single out individual spinous processes due to the ligamentous structures and muscle tissue so tightly supporting the region.

Each thoracic vertebrae aligns itself with a rib of the thoracic cage. T1 with rib 1, T2 with rib 2, and so on down to T12 meeting with the 12th rib. The thoracic region of the vertebral column depicts a change to a backward curvature as can be seen side on in the diagram in your manual. An excessive posterior curvature in this region is known as kyphosis and is depicted by a ‘hump back’. The spinous processes of these vertebrae are the most palpable of the back vertebrae, however developing a good sensitivity in the hands when locating them still requires practice.

Continuing inferiorly, we come to the lumbar vertebrae. Their large size is testament to their role as an import support structure for the upper body. Although consisting of only 5 vertebrae they can play havoc with anyone suffering a lower back complaint. The closer the vertebrae is to the sacrum the greater the possibility that it may be contributing to possible pain and discomfort. This is understandable given that the common problem associated with back pain is lordosis or excessive forward curvature of the spine. In such a position, greater stress is placed on these vertebrae, particularly lower down at L4 & L5.

The sacrum fits nicely into the space between the left and right ossa coxae. Although actually 5 bones, given they are fused we tend to view them as a single entity. This wedged shape bone provides a strong foundation for the pelvic girdle.

Finally, the 4 fused coccyx bones, representing the tail bone. Often out of sight and out of mind, until of course we have been sitting on a hard seat for any length of time or have had the unfortunate fall onto



our rear! Although only small, the coccyx has an important role to play in maintaining the overall ‘plumbline’ of the vertebral column as well as ensuring that the head (at the opposite end of the vertebral column), ‘feels connected’ with the rest of the body.

The thoracic (rib) cage is involved directly in the mechanics of breathing and protects the underlying internal organs. It also provides the support required to the pectoral girdle and hence the connecting upper limbs. The two main sections are the sternum consisting of the manubrium - sternal body - xiphoid process and the 12 pairs of ribs.

The remaining bones of the Axial Skeleton are the middle ear ossicles and the hyoid bone. Although these bones are not relevant when referring to the function of the Axial Skeleton, for convenience we will place them in this category.

Appendicular Skeleton

We will begin with the upper extremity and its point of origin, the pectoral (shoulder) girdle. The pectoral girdle consist of the clavicle anteriorly and scapula posteriorly. It does not include the humerus as is often mistakenly thought. The combination of both these two bones provides a unique arrangement for the integration of muscles around the shoulder joint.

The most proximal bone of the upper limb (ie. upper arm) is the humerus. Moving distally we have the radius and the ulna within the forearm. Keep in mind that the radius is on the thumb side and in reference to the anatomical position this is on the outside (lateral side). Then we have the carpals within the wrist. For ease of identification we can place these bones into two rows with four in each row. Starting with the proximal row first, lateral to medial, we have the scaphoid, lunate, triquetrium and pisiform. Then distally, starting laterally then going medially, we have trapezium, trapezoid, capitate and hamate. Moving further distally towards the hand, we have the bones of the hand itself known as the metacarpals (‘meta’ meaning after) followed by the bones within the fingers known as the phalanges. Keep in mind that each finger has three phalanges and the thumb has two, making up a total of 14 within each hand. The large number of bones found within the hand (and as a result the high number of joints created) enables us to perform a diverse range of specific and integrated movements.

At the lower extremity, the point of origin will be the pelvic girdle. The pelvic girdle is basically broken up into three bones, although the pelvic girdle itself is one distinct bone. The upper part is the ilium. When you put your hands on your hips you are putting them on your ilium and in particular the bone marking known as the iliac crest. The ischium is the lower (inferior posterior) portion and often referred to as the ‘sitting bone’ as it bears much of the weight of the pelvis when in the sitting position. The pubis is the front lower (anterior posterior) part which houses the pubic area. If you join those three bones together you get what is referred to as an ossa coxae. So, more correctly speaking, when linking together the left and right ossa coxae you form the pelvic girdle.

If we now continue on to the lower extremity. First of all starting at the origin (ie. hip), the most proximal bone is the femur (thigh bone). Followed by the patella, which is the kneecap; the tibia, which is the shinbone and the fibula, which is often referred to as the splint bone. The bones within the ankle are called tarsals. They are made up of the talus which is the one closest to the top of the ankle; in underneath (inferiorly) and representing the heel bone is the calcaneus. Then we have the navicular along with 4 distal bones which are the 1st, 2nd and 3rd cuneiform and the cuboid. In particular, be aware of the location of the talus and calcaneus. Then we have the metatarsals, the bones within the foot itself, followed by, once again, the phalanges for the toes.

Make sure you look at a breakdown of the axial and appendicular skeleton according to numbers to help with your understanding. You actually have an activity in your first manual whereby we are asking you to see if you can number the bones within each of these two regions. As is indicated, the total number of bones that you should calculate for the axial skeleton is 80. The total number for the appendicular skeleton is 126. For an overall total of 206.



Bone Markings

What we have here is skeletal terms which are common throughout the body and some of these terms are only found in particular regions. We have what is called a tubercle, a tuberosity and a trochanter. Think of these as bumps and for simplicity think of the tubercle as being a small bump, a tuberosity a medium sized bump and a trochanter a large bump and there are examples given there on a diagram. A foramen is an opening or a hole; a spine being a bony process; a process is a projection; a fossa is a pit or depression; a cavity is like a socket; a groove; a crest; a body is the main part of the bone; a notch which is a indentation or a curve within the bone; an angle is where the bone turns sharply; a border is any straight section of bone; a head is as we see a head being - the start of a bone; a neck is as we understand neck to be - the narrowing below the head; a condyle - a rounded projection; and, a epicondyle being the narrowing before the condyle.

We will now have a look at particular bones in the body and special bone markings for revision.

Vertebrae

Keep in mind the vertebrae has three main sections that we want you to learn. That is the body, which is what each vertebrae sits on top of to create the vertebral column. The spinous process, if you feel down the back of your spine you will feel projections going out posteriorly – that’s the spinous processes. Transverse processes, the projections going out sideways, ie. transversely. You can’t feel these, but you can certainly feel the spinous processes.

Pectoral Girdle

The pectoral girdle, keep in mind again, is made up of simply the clavicle and scapula. The clavicle simply has two markings on it. The medial end known as the sternal end, because it attaches to the sternum and the lateral end is known as the acromial end because it attaches to the acromion process of the scapula, which we will be looking at next.

Scapula

The scapula as you can see is very detailed and part of the reason is because of its odd shape. It is shaped like that to allow all of these markings to exist on it for bone attachment. So what we have got first of all is the superior, medial and lateral borders. So there are three borders on the scapula. Then there is a glenoid cavity and that is where the upper limb inserts to create the shoulder joint. We have two angles; there is a superior angle and an inferior angle. There’s a spine and you will get to know that marking very well because it is a prominent bony marking on the upper back. Then we have two processes, an acromion process and a coracoid process. The acromion process is actually the tip of the shoulder. If you were to feel out along the tip of your shoulder to the end of your shoulder, you will feel a bony projection which is the acromion process. The coracoid process on the other hand is a finger-like projection coming through anteriorly just below the clavicle at the front of your chest. The superior notch is not one that we are going to refer to much, but this is a little notch found just to the side of the coracoid process. There are three fossas: a supraspinous fossa (supra means above/spinous comes from spine/fossa means a depression). So, in other words it is a depression above the spine of the scapula. So you can see that quite readily if you look at the spine of the scapula, when looking above you will notice a large area which is represented by the supraspinous fossa. Infraspinous fossa is obviously found below the spine of the scapula, so it is a depression below the spine of the scapula. And the third fossa is subscapular fossa (‘sub’ meaning underneath) and that‘s what it is, it is underneath the scapula, ie. it is on the anterior aspect of the scapula. And finally there are two tubercles: there is a supraglenoid tubercle (‘glenoid’ coming from glenoid cavity/‘supra’ meaning above), so it is a tubercle or a bump above the glenoid cavity; and infraglenoid tubercle is obviously the bump below the glenoid cavity.

Upper Limb



The upper limb, starting from the shoulder itself, we have the humerus and let’s look at the proximal end first, in other words the end closest to the shoulder/origin of the limb. We have a head which fits into glenoid cavity of the scapula. It then narrows to the neck. Then either side of the neck you have bumps - a greater tubercle and a lesser tubercle. The greater tubercle is on the lateral aspect just below the acromion process of the scapula. The lesser tubercle is on the medial aspect. In between the two tubercles you have the intertubercular groove (‘inter’ meaning between/’tubercular’ in reference to the left and right tubercles). Then we have the shaft. On the shaft on the lateral aspect about a third to a half of the way down there is a roughened area which is known as the deltoid tuberosity. If we now look at the distal end you will see that the shaft flares to become what’s known as the medial and lateral epicondyle (‘epi’ meaning above). Then it becomes the rounded projections at the end which are known as the condyles which have particular names known as the trochlea and the capitulum. The trochlea is the knuckle-like shaped projection which meets the ulna on the medial side of the elbow. The capitulum is the round ball-like projection which meets the radius on the lateral side of the elbow. You will notice that there is a depression on the front and the back of the humerus at the distal end. These depressions are known as the coronoid fossa and the olecranon fossa. The coronoid fossa being on the anterior aspect and the olecranon fossa being on the posterior aspect.

We will now move onto the ulna and the radius.

First of all with regard to the ulna, there is a trochlea notch. The word trochlea has been presented here again because this notch fits into the trochlea of the humerus as just mentioned above, hence the word trochlea notch. Then we have a radial notch. The radial notch is the carved out area of the ulna in which the head of the radius fits into, therefore the term ‘radial’ notch. Then we have the olecranon process which is actually the point of your elbow. So when you lean on your elbow you are actually leaning on your olecranon process. Then we finally have the coronoid process which is the prominent process just distal to the trochlea notch on the anterior aspect. Keep in mind that the coronoid process, when you bend your elbow, locks into the coronoid fossa (anteriorly). And when you straighten your elbow the olecranon process locks into the olecranon fossa (posteriorly).

Let’s look at the radius. We have the head of the radius which rotates within the radial notch of the ulna. We have the neck of the radius beyond which can be found a roughened area called the radial tuberosity. If we look down to the distal end of the ulna and radius, the width of the wrist can be designated by the styloid processes of the ulna and the radius.

Pelvic Girdle

The pelvic girdle consists of a socket which is the acetabulum. The three parts of the ossa coxae, as mentioned before, are the ilium, ischium and pubis. And there is a large opening at the base formed by the junction of the ischium and pubis known as the obturator foramen.

Let’s look at each individual bone within the pelvic girdle.

First of all the ilium. The ilium consists of the iliac crest, as mentioned before, when you put your hands on your hips you are putting your hands on your iliac crest. The iliac crest runs from the front (anteriorly), goes along the side of the body (laterally) and then heads right around to the back (posteriorly). In line with the top of your pants and possibly just in underneath your belt line you can palpate a bony protrusion or projection called the anterior superior iliac spine or ASIS for short. ‘Anterior’ meaning the front, ‘superior’ meaning it’s the one above, ‘iliac’ coming from ilium, ‘spine’ meaning it is a projection. So if we have a superior projection then we must have an inferior one and we do, it is called the anterior inferior iliac spine or AIIS. That cannot be palpated; it is deep to the front of the hip. If we then track backwards, we will come to the end of the iliac spine posteriorly where we get a projection again called the posterior superior iliac spine or PSIS. That can be palpated; they look like two dimples on the surface of the body level with the start of the sacrum. Below that then, of course, must be an inferior projection which is called the posterior inferior iliac spine or PIIS which is deep and cannot be palpated We also have a greater sciatic notch which can’t be palpated and



iliac fossa which can’t be palpated. We move onto the ischium. We have the ischial spine which cannot be palpated, followed by the lesser sciatic notch which cannot be palpated and then we have the ischial tuberosity which can be palpated. That’s the large bony projection at the base of the buttocks. And at the front we have the pubic area designated by the pubic crest or pubic bone as can be palpated above the genitalia.

Lower Limb

With the femur, we have at the proximal end the head followed by the neck, followed by a large projection on the outside which can be palpated called the greater trochanter. On the inside, difficult to palpate is the lesser trochanter. Just at the base of the buttocks we have the gluteal tuberosity and we also have posteriorly, running down the length of the shaft of the femur the roughened ridge known as the linea aspera (linea = line/aspera = rough). At the distal end we have two condyles, a medial and a lateral condyle. They’re the large rounded projections which make up the superior part of the knee joint. As previously discussed with the humerus, prior to the condyles we have the epicondyles, medial and lateral.

If we then move onto the bones of the lower leg, we have the tibia and fibula. The tibia is the shin bone and everyone has probably knocked their shin bone on something at some stage. It is particularly sensitive because the bone is very close to the surface of the lower leg and creates quite an edge anteriorly along its length. It can be palpated quite readily. We have the medial and lateral condyle with regard to the tibia and then at the front of the tibia we have an obvious bump just below the patella called a tibial tuberosity. If we now look at the fibula. The fibula consists of the head of the fibula which can be palpated quite easily on the lateral side of the lower leg - make sure you are laterally when palpating as it is on the side of the leg just below the knee joint. Then we have the neck. As you palpate off the head down towards the neck you lose the fibula due to superficial muscles covering the shaft all the way down to the ankle. Distally, at the ankle we have the malleolus on the fibula, the lateral malleolus, or what is referred to as the ankle on the outside. Then on the inside we have a medial malleolus which is part of the bony projection of the tibia and is the ankle on the inside.

Let’s now review Musculoskeletal Anatomy - The Articular System.

10.2 The Articular System

Classification of Joints

Firstly, classification of joints. Keep in mind that there are three types of joints in the body and they are classified according to their structure. Fibrous joints, a typical example are the sutures of the skull. Cartilaginous joints, think of cartilage and a good example is the cartilage between the vertebrae of the vertebral column and thirdly the synovial joints. Most of the joints in the body are synovial joints and they house synovial fluid within a joint capsule.

So what we will do is particularly look at synovial joints because they are the most relevant joint to us as massage therapists and most of the joints in the body, as mentioned, are synovial joints. So there are six types of synovial joints. First of all a plane joint is simply a synovial joint which moves side to side or slides or slips and a good example are the joints found within the wrists and the ankles. In other words the intercarpal joints of the wrist and the intertarsal joints of the ankle. Moving on to the next one, the hinge joint. Think of it as a door hinge, it typically just bends and straightens. Good examples are the knee and the elbow. The pivot joint does what the word says, it pivots or rotates and a good example is, as mentioned before, the joint between the atlas and the axis, which allows you to rotate/turn your head from side to side. Another good example is the rotation of the forearm where the radius rotates in relation to the ulna. Condyloid or ellipsoid joint is a joint which provides a greater range of movement than a hinged joint. It not only can bend and straighten, but it can also move sideways. A good example of that is your knuckles. Your knuckles can bend and straighten the fingers as well as enabling you to spread your fingers sideways. Another good example is at the wrist joint between the radius and the carpal bones, ie. the radio-carpal joint, thereby enabling a greater



freedom of movement of the wrist. Saddle joints - there is only one true saddle joint in the body and that is the joint at the base of the thumb. The saddle joint is very similar to the condyloid joint, except that the movement created is much better, ie. a greater range of movement is permitted. So with this joint you can also do the bending and straightening and the sideway movements. You would agree that the movement of your thumb is much freer than the movements of your fingers. Ball and socket joint - there are two within in the body. One found at the shoulder and one found at the hip. These create by far the greatest movement of any joint. They are designed to encourage full range of motion around the joint.

Synovial Joint Movements

Let us now look at some joint movements created by synovial joints. It is really important that you always refer back to the anatomical position, particularly if you’re a little bit confused about what type of movement may be happening at a given joint. Always refer back to the anatomical position because when the body is in this position, all joints are in extension, i.e. they are considered to be straight. So when keeping that in mind, starting from the anatomical position, you can work out more often than not, the movements occurring at most of the joints in the body.

Let’s look first of all at flexion and extension. Flexion is when you bend your elbow; extension is simply when you straighten your elbow. When you bend a joint it is flexion, when you straighten it, it is extension. Next is abduction/adduction. With abduction think of abduct, if you abduct someone you take them away, that’s what you are doing in this situation, you are taking the limb away from the midline of the body. With adduction, think of add, adding the limb back to the midline of the body, ie. bringing it back in. A combination of those four movements gives you circumduction. You can create a flexion/abduction/adduction/extension movement all in the one motion which creates a cone-shaped movement known as circumduction. This is distinctly different from rotation – this is where the limb remains in a stationary position and simply rotates around its own axis. You can do this also by turning your head sideways as in saying no. Those six movements are the general movements within the body.

There are more specific movements found in particular areas of the body. A common one is supination/pronation of the forearm. What happens is the radius rotates or pivots so that it turns across the ulna into a pronation position or a palms-down, ‘patting the dog’, position. Returning the radius back into a palm-up position is supination. In the anatomical position, the forearm is in supination. Inversion/eversion and plantar flexion/dorsiflexion all relate to the foot. When you typically roll-over onto the outside of your ankle you are going into an inverted position. It is much more difficult to roll over on your ankle into an everted position. In the anatomical position the foot is neither inverted or everted, it is in a neutral position in relation to this movement. Plantar flexion is when you point your toes down; dorsiflexion is when you point your toes up. In the anatomical position the foot can be referred to as being in dorsiflexion or in a neutral position, ie. neutral being neither dorsiflexed or plantarflexed. Protraction/retraction and elevation/depression relate to the skull and scapula. Protracting the scapula means bringing the scapula forwards as in reaching for the salt ‘n’ pepper on the table, ie. the scapula moves anteriorly. Retraction is when you are bringing your arm back. In other words, retracting the scapulars back towards each other. A little like ‘coming to attention’ where you straighten your body up, ie. the scapula moves posteriorly. In the anatomical position the scapulars are neutral in relation to these movements, however they could well be protracted or retracted in a person’s normal postural position due to muscle tightness and postural deviations, ie. the person could be quite restricted in their muscle tone in the chest area, thereby pulling the scapula forward into a protracted position (ie. rounded shoulders), which for them is their ‘normal’ body position. Elevation is when you shrug your shoulders upwards and depression is when you drop your shoulders back down. In effect, your scapula is moving upwards (superiorly) in elevation and downwards (inferiorly) in depression. In the anatomical position one would expect that the scapulars would be in depression due to gravity acting on the body. However, in the example of a highly tensed individual depicted by tightening within the neck and shoulders, the scapulars could well be permanently raised into an elevated position (ie. hunched shoulders) and may represent the



person’s ‘normal’ postural position. Deviation relates to movement of the wrist away from the midline of the body. Ulnar deviation is where the hand deviates to the ulna side, ie, medially. Radial deviation is where the hand deviates to the radial side, ie. laterally. In the anatomical position the hand is neutral in relation to these movements. Opposition is simply contacting opposite thumb and finger.

Regarding the additional movements, gliding if you can recall, is a slipping and sliding movement, such as found within the wrists and the tarsals. When considering lateral flexion let’s discuss this movement with regard to the axial skeleton. If you do a sideways movement of the axial skeleton for example, where your trunk moves sideways or your head moves sideways, then that can be commonly referred to as a sideways bend. In other words lateral flexion = sideways/bend. This is distinctly different when looking at the appendicular skeleton, ie. sideways movement by the limbs is referred to as abduction. Lateral flexion and abduction are movements where a body part undertakes a deviation away from the midline of the body. In the anatomical position there are no deviations occurring, ie. the body is in a neutral position. When considering hyperextension, keep in mind that there are some joints in the body that not only extend, but have the ability to hyperextend. In other words, they can move beyond extension. For example your head, you can tilt your head forward into flexion (chin to chest), then return/extend it back to the neutral or anatomical position which is extension, then you can drop your head back behind you (eyes to ceiling) which is hyperextension.

The purpose of learning about bones and bone markings in Musculoskeletal Anatomy - The Skeletal System and joint movements in Musculoskeletal Anatomy - The Articular System, is to allow you to then use that information, together with the muscles in Musculoskeletal Anatomy - The Muscular System, so that you can get a greater understanding of the workings of the Musculoskeletal System.

Let’s now review Musculoskeletal Anatomy - The Muscular System.

10.3 The Muscular System

Let’s begin by looking at a muscle. A muscle has two ends. One end is the origin or fixed end which is usually the proximal end and the other end is the insertion or moveable end which is usually the distal end. It is important that you have a good concept of which end is the origin and which end is the insertion. Because if you don’t, it is very difficult to understand what movements a specific muscle can do. So let’s take that one step further by looking at the different types of muscle contractions there are in the body. A muscle can perform a contraction where the muscle length shortens. That’s called a concentric contraction. A muscle can contract where it actually lengthens during contraction and that’s called an eccentric contraction. A muscle can also contract where it doesn’t change in length during contraction and that is called an isometric contraction.

What we’re doing in terms of having an understanding about the movement that a muscle may produce is keeping in mind that we are always referring to a concentric contraction, ie. when the muscle shortens in length. So in other words, when the insertion moves closer to the origin. Keep in mind that the origin is the fixed end, theoretically it does not move. The insertion is the moveable end, it moves. So in a muscle contraction, the insertion moves closer to the origin. As a result the muscle shortens, producing a concentric contraction. So the muscle may actually be involved in producing an eccentric contraction or an isometric contraction, but we don’t look at these movements when deciding on a muscle’s action. A good way to think of this is that muscles pull, they don’t push. So if you can think of a muscle pulling on its insertion so the insertion gets closer to the origin, then all you do is think of, okay, what movement has that produced? Your answer will then be the action for that muscle.

Keep in mind that what we are doing also is looking at muscles in terms of four different categories. They can be a prime mover, or what is called an agonist, in a particular movement at a joint. It can be an antagonist. In other words, it opposes a particular movement. Now the word “opposes” in some way has a negative connotation to it. What’s actually happening there is that it is providing the opposite movement which is important when you consider that muscles never work in isolation. So, if



a prime mover on one side of the body is contracting to create movement at the joint, its opposing muscle (agonist) on the opposite side of the body will be inhibited (ie. it will be prevented from contracting to perform the opposite movement). This ensures an effective joint movement by the prime mover. Although we are looking at them in isolation to gain an understanding of their individual actions, in general everyday movements, many muscles are acting at once to create an endless array of bodily positions. A fixator is a muscle that simply supports or stabilisers a particular part of the body to thereby enable other muscles to work satisfactorily. It will often be contracting isometrically (ie., its length doesn’t change during the contraction) to help ‘hold’ the bodypart in a certain position. And finally, a synergist is simply a helper. It assists the prime mover in performing a particular movement.

It is worthwhile at this stage in elaborating on the layout of the muscles of the body found in your notes. Using the biceps brachii example shown in your Musculoskeletal Anatomy - The Muscular System manual, you have the name of the muscle given, then a brief description of the muscle. You have in a table format the origin, insertion and action. Keep in mind that the origin is the fixed end and that’s shown in the diagram in terms of the points of attachment. Then you have the insertion and there is a diagram showing the points of attachment. Then the action can be determined by looking at the line of pull which is shown there in a diagram as well. Looking at the line of pull which is (point 3), just imagine that the insertion is moving closer to the origin. As a result what is going to happen is the elbow is going to bend, or in other words, flex. Hence the action at the elbow for the biceps brachii is flexion. It will also do some flexion of the shoulder and because it attaches to the radius, it will also create supination of the forearm when the forearm is in a pronation position. So try and avoid rote learning this or recalling it off by heart. See if you can, 1. imagine where the muscle is located in the body, 2. have an understanding of its origin and insertion and 3. then work out what the action is based on the muscle pulling the insertion closer to the origin.

Let’s now look at the additional notes that you have received in this manual.

11. Muscle Groups

First of all, muscle groups. List the muscles found within the following categories. So what we are going to do here is look at just the major muscles within each area.

11.1 Muscles of the Anterior Neck

With muscles of the anterior neck we have sternocleidomastoid and scalenes and you may even include upper trapezius because the upper trapezius does run forward a little bit and can be seen anteriorly. However, trapezius is considered to be a posterior muscle.

11.2 Deep Muscle Group of the Back

Muscles deep to the back - the erector spinae group.

You have got spinalis, longissimus and iliocostalis. It is not necessary to know specifically origin insertions for these groups due to the complexity of these muscles, simply using the term ‘many and varied’ is satisfactory.

11.3 Muscles of the Posterior Abdominal Wall

If you were to imagine projecting your vision through the abdomen to the back wall of the abdomen you would be able to see the iliopsoas muscle (which consists of the iliacus and the psoas) and the quadratus lumborum.

11.4 Muscles of the Anterior Abdominal Wall



In other words the abdominal muscles, you have the rectus abdominis which runs straight down the middle, then layer upon layer (superficial to deep) are the external oblique, internal oblique and transverse abdominis.

11.5 Muscles of the Thorax involved in Respiration

So of course we have the diaphragm mainly involved here. Also the intercostal muscles - the internal and external intercostal muscles between the ribs. You may also have in there the scalenes which attaches to the first and second rib, pectoralis minor which attach to the third, fourth and fifth rib and pectoralis major which attaches to the first 6 ribs, hence they will all act on the rib cage.

11.6 Muscles of the Gluteal Region

We have the gluteals themselves, the gluteus maximus, medius and minimus and of course piriformis, one of the eight lateral rotators of the hip.

11.7 Muscles of the Scapular Stabilisation

So what you are really talking about here are muscles which run from the scapula to the axial skeleton. If they’re going from the scapula to the humerus, they’re really not going to be involved in stabilising the scapula due to the fact that the anchor point is on a moveable limb.

Whereas if they can anchor to the axial skeleton, then it provides an excellent anchor point for providing stabilisation to the scapula. So these muscles are particularly good in their role as fixators within the body.

So we have, of course, levator scapulae going from the medial border of the scapula near the superior angle and heading up and anchoring to the transverse processes of the cervical vertebrae. We have the trapezius which runs along the spine of the scapula, acromion process & lateral clavicle and heads across to provide a lengthy anchor point from the skull - along the spine - to T12. The rhomboids are found between the medial border of the scapula and the vertebral column. Pectoralis minor is found on the anterior aspect of the body and travels from the coracoid process of the scapula and attaches to ribs three, four and five. And finally anterior serratus, which comes from the medial border, tracks between the scapula and the thorax posteriorly and heads laterally, wrapping around the rib cage and attaching to the lower eight ribs, anterior-laterally.

11.8 Muscles of the Rotator Cuff Group

Think of rotator meaning the muscles being involved in rotation and these muscles are primarily involved in the rotation of the shoulder. ‘Cuff’ coming from the fact that the muscles in combination create a musculotendinous cuff to thereby hold the head of the humerus into the socket of the shoulder.

So what we have got here is ‘S’ stands for supraspinatus, ‘I’ for infraspinatus, ‘T’ for teres minor and ‘S’ for subscapularis. As a group, they are involved in holding the upper limb into the socket created by the scapula, as well as assisting in much of the rotation movements of the shoulder. So group by which these muscles are named, rotator cuff, gives a clear message of the role of this group, ie. rotation and support.

11.9 Muscles which cross the Shoulder Joint

Muscles which cross the shoulder joint can be studied in two ways.



Firstly, by looking at all of the muscles that are attached to the upper limb and then deciding which ones track across the shoulder joint, or secondly, by looking at the muscles that attach to the scapula and looking at which ones track across the shoulder joint and attach to the upper limb.

Study Method #1

Okay, well let’s start by looking at the upper limb and discussing the muscles which attach to the humerus.

We have got the SITS muscles: supraspinatus, infraspinatus and teres minor attaching to the greater tubercle of the humerus. Then we have subscapularis, the last one of the SITS muscles attaching to the lesser tubercle of the humerus.

We have the triceps which attaches to the humerus at the olecranon process and the posterior shaft. However, the biceps doesn’t attach to the humerus, so we need to leave that one out at the moment. The deltoid attaches to the humerus at the deltoid tuberosity on the lateral shaft.

Latissimus dorsi attaches to the humerus at the intertubercular groove along with teres major and pectoralis major. So there are three muscles attaching to the intertubercular groove.

We also have brachialis attaching to the shaft anteriorly and brachioradialis attaching to the shaft distally. And we also have coracobrachialis attaching to the shaft medially.

Review

So re-capping the muscles attaching to the humerus, we have the SITS muscles (the four rotator cuff muscles), triceps, deltoid, latissimus dorsi, teres major, pectoralis major, brachialis, brachioradialis and coracobrachialis. Which of these muscles cross the shoulder joint? Well the four SITS muscles do because they have an important role to play in stabilising the shoulder joint and they do this by attaching to the scapula. The triceps does because the long head of the triceps attaches to the scapula just below the glenoid cavity. The deltoid does because it attaches to both the scapula and the clavicle. Latissimus dorsi does because it tracks posteriorly and attaches along the distal half of the vertebral column. Pectoralis major does as it tracts anteriorly across to the clavicle, sternum and ribs. Brachialis doesn’t because it tracks down to the forearm. Brachioradialis doesn’t because it also tracks down to the forearm. Coracobrachialis does as it tracks anteriorly and attaches to the coracoid process of the scapula. So we have 10 out of the 12 muscles mentioned which are attached to the humerus and then cross the shoulder joint to attach onto the pectoral girdle or the axial skeleton. Circle the 10 muscles on your list which cross the shoulder joint.

Study Method #2

If we now look at the second method which involves examining the muscles attaching to the scapula. We will then repeat the exercise and look at which muscles travel from the scapula, cross the shoulder and attach to the humerus.

So we’ve got once again the SITS muscles that are attached to the scapula. We have the supraspinatus attaching on the superior-posterior aspect in the supraspinous fossa. Infraspinatus attaching on the posterior-inferior aspect in the infraspinous fossa. Teres minor attaching on the lateral margin of the posterior scapula, at the inferior angle end and blending closely with infraspinatus. Subscapularis attaching on the anterior aspect in the subscapular fossa.

Triceps attaches on the inferior lip of the glenoid cavity identified as the infraglenoid tubercle. The long head of the biceps attaches to the superior lip of the glenoid cavity identified as the supraglenoid tubercle. The short head of the biceps attaches to the coracoid process.



The deltoid attaches to the spine of the scapula & acromion process (along the inferior margin) and the trapezius also attaches to the spine of the scapula & acromion process (along the superior margin).

Interestingly, as the latissimus dorsi travels transversely from the back across towards its insertion point on the humerus, it makes slight attachment onto the inferior angle of the scapula (this point of attachment is neither referred to as a point of origin or insertion).

Teres minor attaches to the lateral border of the scapula, above teres major, at the axilla end.

Pectoralis minor attaches to the coracoid process. Coracobrachialis also attaches to the coracoid process.

Anterior serratus attaches to the medial border of the scapula from the underside (anterior aspect). Levator scapulae attaches to the medial border between the level of the spine of the scapula and the superior angle. The rhomboids also attaches to the medial border, below the levator scapula, between the level of the spine of the scapula and the inferior angle.

Which of these muscles cross the shoulder joint and which attach to the axial skeleton?

Review

Let’s again list the muscles in a column (List 2) and then take note of where they go.

All the SITS muscles cross the shoulder joint as they head towards their attachment onto the humerus, so does the triceps and the biceps. The deltoid also crosses to the shoulder joint. However the trapezius doesn’t cross the shoulder joint, from the scapula and clavicle it travels inwards towards the skull and vertebrae column. Latissimus dorsi crosses the shoulder joint to attach onto the humerus and teres major travels along with latissimus dorsi to the humerus also. Pectoralis minor however, attaches to ribs 3 - 5. Coracobrachialis crosses the shoulder joint, attaching to the humerus. Anterior serratus attaches to the ribs. Levator scapulae attaches to the cervical vertebrae (transverse processes) and the rhomboids attach to C7 through to T5 (spinous processes).

So out of the 15 muscles that we have listed that attach to the scapula, there are five that don’t cross the shoulder joint. And what are they? Trapezius, pectoralis minor, anterior serratus, levator scapulae and the rhomboids. And keep in mind that if you look back at the muscles we listed that are involved in scapular stabilisation, these five muscles are the muscles mentioned.

In Summary

So in summary, of the muscles that attach to the scapula, if they don’t go across the shoulder joint and attach to the upper limb to create movement of the shoulder, then they will be going to the axial skeleton to act as stabilisers of the scapula.

Keep in mind, that when we were reviewing muscles which attach to the humerus (List 1), we didn’t mention the biceps, because the biceps doesn’t attach to the humerus (it attaches to the radius in the forearm), however it does cross the shoulder joint. So we need to add the biceps brachii as an ‘extra’ on List 1.

Also when we’re looking at muscles which attach to the scapula (List 2), we didn’t include pectoralis major (it attaches to the clavicle, sternum and ribs), however it does cross the shoulder joint, so we need to include pectoralis major as an ‘extra’ on List 2.

You will notice from your two lists that each group has 10 muscles plus 1 extra that needed to be added for a total of 11. In the case of the humerus being our starting point (List 1) we needed to add the biceps. In the case of beginning with the scapula (List 2), we needed to add pectoralis major.



11.10 Muscles which cross the Elbow Joint

Anteriorly we have the biceps, the brachialis, the brachioradialis and the forearm flexors. Posteriorly we have the triceps and the forearm extensors.

11.11 Muscles of the Posterior Thigh

As a muscle group we have the hamstrings, consisting of the biceps femoris, semitendinosus and semimembranosus.

11.12 Muscles of the Medial Thigh

Muscles of the medial thigh consist of the pectineus, the adductor group - adductor magnus, adductor longus and adductor brevis and the gracilis.

11.13 Muscles of the Anterior Thigh

Muscles of the anterior thigh consist predominantly of the quadriceps group - rectus femoris, vastus medialis, vastus lateralis and vastus intermedius. We can also include tensor fascia latae - although the fascia tracks laterally along the thigh ending below the knee, the muscle belly sits anteriorly at the hip. Sartorius, originating from the same position, sits medially to tensor fascia latae and tracks across the thigh ending medially below the knee.

11.14 Muscles which cross the Hip Joint

Let’s just look at the major muscles here. So we have iliopsoas, rectus femoris within the quadriceps group, tensor fascia latae & sartorius. We have all three hamstring muscles - biceps femoris, semitendinosus & semimembranosus, as well as the three gluteal muscles - gluteus maximus, gluteus medius & gluteus minimus. We also have three adductor muscles - adductor magnus, adductor longus & adductor brevis and finally gracilis.

11.15 Muscles of the Ante rior and Lateral Lower Leg

Within the anterior group we have the tibialis anterior. Within the lateral lower leg group we have the peroneus group and in particular we are referring to peroneus longus.

11.16 Muscles of the Posterior Lower Leg

And finally, with regard to muscles of the posterior lower leg, we have gastrocnemius and soleus.



. See how many of these muscles you can recall by listing them below.

1. Muscles of the Anterior Neck [2]

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2. Deep Muscle Group of the Back [3]

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3. Muscles of the Posterior Abdominal Wall [2]

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4. Muscles of the Anterior Abdominal Wall [4]

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5. Muscles of the Thorax involved in Respiration [5]

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6. Muscles of the Gluteal Region [4]

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7. Muscles of Scapular Stabilisation [5]

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8. Muscles of the Rotator Cuff [4]



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9. Muscles which cross the Shoulder Joint [11]

LIST 1 LIST 2 Humerus [10] Scapula [15]

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10. Muscles which cross the Elbow Joint [6]

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11. Muscles of the Posterior Thigh [3]

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12. Muscles of the Medial Thigh [5]

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13. Muscles of the Anterior Thigh [6]

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14. Muscles which cross the Hip Joint [14]

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15. Muscles of the Anterior & Lateral Lower Leg [2]

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16. Muscles of the Posterior Lower Leg [2]

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12. Muscle Actions

To complete our overview of Musculoskeletal Anatomy let’s specifically look at the muscles and categorise them according to their actions.

12.1 Muscles Acting on the Arm

Let’s begin with the first table - muscles acting on the arm.

Pectoralis major is a prime mover in shoulder flexion and also in adduction (write ‘PM’). It’s also involved in medial rotation (so you can give medial rotation a tick). Latissimus dorsi is a prime mover in shoulder extension; it is also a prime mover in shoulder adduction along with pectoralis major. You now have ‘PM’ written twice under the adduction column for the shoulder joint - this indicates that you can have more than one muscle being a prime mover in a given movement. In the case of these two muscles, pectoralis major acts anteriorly in adduction and latissimus dorsi posteriorly in adduction. Latissimus dorsi is also involved in medial rotation. The deltoid is a very busy muscle because there are three parts to it and it’s the most prominent muscle on the shoulder. It’s a prime mover in flexion because of the anterior fibres, it’s a prime mover in extension because of the posterior fibres and it’s a prime mover in abduction because of the middle fibres. It is also involved in assisting the rotator cuff muscles in medial/internal rotation (anterior fibres) and lateral/external rotation (posterior fibres). Subscapularis is the prime mover in medial rotation and is assisted by latissimus dorsi and the posterior deltoid as already mentioned. Supraspinatus also assists the deltoid in abduction. Infraspinatus and teres minor, together, are the prime movers in lateral rotation. Notice that the prime movers in rotation (medial and lateral) of the shoulder, are the responsibility of the rotator cuff muscles. Teres major, its movements are exactly the same as latissimus dorsi because it runs beside and follows the same line as latissimus dorsi, also inserting onto the intertubercular groove. It acts as a synergist in each of the movements - extension, adduction and medial rotation. Coracobrachialis assists in flexion and adduction. Although only weak, biceps assists in flexion of the shoulder.

We will now move on to the column for action of the elbow joint. Continuing with biceps brachii, it is a prime mover in flexion of the elbow. Referring momentarily back to the shoulder joint, the triceps assist in extension and adduction of the shoulder (due to its attachment onto the infraglenoid tubercle of the scapula). With regard to the elbow, being the only muscle on the posterior aspect of the humerus, the triceps is the prime mover in extension of the elbow. Brachialis is also a prime mover in flexion of the elbow along with biceps brachii (brachialis promotes a line of pull on the ulnar side of the forearm and biceps brachii promotes a line of pull on the radial side). Brachioradialis is a strong muscle and assists in flexion of the elbow. The forearm flexors are obviously involved in flexion - flexion of the wrist and fingers; and the forearm extensors are involved in extension of the wrists and fingers.

12.2 Muscles Acting on the Leg

Let’s now move on to the second table - muscles acting on the leg.

Rectus femoris, which is the main quadriceps muscle, is the only one of the four which actually crosses the hip joint, attaching to the AIIS. It is involved in the flexion of the hip, however, suprisingly enough it is not considered a prime mover in hip flexion. It also acts on the knee joint and is a prime mover in extension of the knee along with the remaining quadriceps muscles, ie. the vastus muscles (vastus medialis, vastus lateralis and vastus intermedius). The vastus muscles obviously don’t act on the hip joint because they don’t cross the hip joint. Iliopsoas (consisting of two muscles - iliacus and psoas) is actually the prime mover of hip flexion. Sartorius assists in flexion of the hip, abduction of the hip and lateral rotation of the hip. The muscle is most active when all three movements are performed together to depict a cross legged position, which also includes flexion of the knee. It is a weak flexor of



the knee. So just think of a cross legged position and in that position you have the hip in flexion, abduction and lateral rotation, along with flexion of the knee. Tensor fascia latae assists in flexion, abduction and medial rotation of the hip. The adductors are prime movers obviously in adduction, bringing the leg back into the midline and assists lateral rotation - keep in mind the adductors run towards the femur and attach to the posterior aspect of the femur along the linear aspera, therefore producing a lateral rotation. Both pectineus and gracilis assist in adduction of the hip. The gluteus maximus, the main gluteal muscle, is a prime mover in extension of the hip and assists in lateral rotation. Gluteus medius is a prime mover in abduction and assists in medial rotation. Piriformis is a synergist and assists in abduction and lateral rotation. The hamstrings are the only muscle group on the posterior thigh and as a group are the prime movers in hip extension as well as knee flexion. Gastrocnemius assists in knee flexion as it crosses the knee joint and is a prime mover in plantar flexion. Soleus is also a prime mover in plantar flexion. The gastrocnemius acts from the attachment at the femur and the soleus acts from the attachment at the tibia/fibula. Peroneus assists in plantar flexion and eversion. And tibialis anterior does the opposite movements to peroneus, being a prime mover in dorsiflexion and assisting in inversion.

It is recommended that you review the above information a number of times to help reinforce your understanding and to assist you in your overview of Musculoskeletal Anatomy.

- Refer to the tables below and try to recall the actions of individual muscles using the concept of muscles pulling rather than pushing, ie. so that the insertion gets closer to the origin. If you think the muscle is a Prime Mover put ‘PM’ in the relevant column. For example, if you think the pectoralis major is a prime mover in flexion of the shoulder (ie. primarily responsible for the movement) then put ‘PM’ in the flexion column for this muscle. If you don’t think it is a prime mover but it does assist in the movement (ie. it’s a synergist) then simply tick the flexion column. If you do not consider it to be involved in the movement at all then leave the column blank.

10. Overview

Before you begin

Let’s review



Table 1 - Muscles acting on the Arm

Action of the

Shoulder Joint Action of the Elbow Joint

Action of the Wrist/Finger

s

Flex Ext Abd Add MR LR Flex Ext Flex Ext

Pectoralis Major

Latissimus Dorsi

Deltoid

Subscapularis

Supraspinatus

Infraspinatus

Teres Minor

Teres Major

Coracobrachialis

Biceps Brachii

Triceps Brachii

Brachioradialis

Forearm Flexors

Forearm Extensors



Table 2 - Muscles acting on the Leg

Action of the

Hip Joint

Action of the Knee

Joint

Action of the Ankle Joint

Flex Ext Abd Add MR LR Flex Ext Dor Plan Inv Ever

Rectus Femoris

Vastus Muscles

Iliopsoas

Sartorius

TFL

Adductors

Pectineus

Gracilis

Gluteus Maximus

Gluteus Medius

Piriformis

Hamstrings

Gastroncnemius

Soleus

Peroneus

Tibialis Anterior

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