Shoulder And Arm Muscles

Front 1

Infraspinatus

Back 1

O: infraspinatus fossa of scapula

I: greater tubercle of humerus

A: externally rotate and adduct shoulder; stabilize head of humerus in glenoid cavity

I: suprascapular nerve C4, 5, 6

Front 2

Teres minor

Back 2

O: lateral border of scapula

I: greater tubercle of humerus

A: externally rotate and adduct shoulder; stabilize head of humerus in glenoid cavity

I: axillary nerve C5, 6

Front 3

Teres major

Back 3

O: inferior angle and lateral border of scapula

I: crest of lesser tubercle of humerus

A: extend, adduct, and internally rotate shoulder

I: lower subscapular nerve C5, 6, 7

Front 4

Supraspinatus

Back 4

O: supraspinous fossa of scapula

I: greater tubercle of scapula

A: abduct shoulder; stabilize head of humerus in glenoid cavity

I: suprascapular nerve C4, 5, 6

Front 5

Subscapularis

Back 5

O: subscapular fossa of scapula

I: lesser tubercle of humerus

A: internally rotate shoulder; stabilize head of humerus in glenoid cavity

I: upper and lower subscapular nerve C5, 6, 7

Front 6

Serratus anterior

Back 6

O: external surfaces of ribs 1-9

I: anterior surface of medial scapular border

A:

-w/ ribs fixed = abduct, depress, and upwardly rotate scapula; hold medial border of scapula against rib cage

-w/ scapula fixed = may elevate thorax during forced inhalation

I: long thoracic nerve C5, 6, 7, 8

Front 7

Pectoralis minor

Back 7

O: ribs 3-5

I: medial surface of coracoid process of scapula

A: depress, abduct, and downwardly rotate scapula

-w/ scapula fixed = assist to elevate thorax during forced inhalation

I: medial and lateral pectoral nerves C6, 7, 8, T1

Front 8

Pectoralis major

Back 8

O: medical clavicle, sternum, and cartilage of ribs 1-6

I: crest of greater tubercle of humerus

A:

-all fibers = adduct and internally rotate shoulder; assist to elevate thorax during forced inhalation

-upper fibers = flex and horizontally adduct shoulder

-lower fibers = extend shoulder

I:

-upper fibers = lateral pectoral nerve C5, 6, 7

-lower fibers = medial and lateral pectoral nerves C6, 7, 8, T1

Front 9

Subclavius

Back 9

O: 1st rib and cartilage

I: inferior surface of clavicle

A: depress clavicle and draw it anteriorly; elevate first rib; stabilize sternoclavicular joint

I: subclavian nerve C5, 6

Front 10

Deltoid

Back 10

O:

-anterior fibers = lateral clavicle

-middle fibers = acromion

-posterior fibers = spine of scapula

I: deltoid tuberosity of humerus

A:

-all fibers = abduct shoulder

-anterior fibers = flex, internally rotate, and horizontally adduct shoulder

-posterior fibers = extend, externally rotate, and horizontally abduct shoulder

I: axillary nerve C5, 6

Front 11

Triceps brachii

Back 11

O:

-long head = infraglenoid tubercle scapula

-lateral head = posterior surface of proximal half of humerus

-medial head = posterior surface of distal half of humerus

I: olecranon process of ulna

A:

-all heads = extend elbow

-long head = extend and adduct shoulder

I: radial nerve of C6, 7, 8, T1

Front 12

Biceps brachii

Back 12

O:

-long head = supraglenoid tubercle of scapula

-short head = coracoid process

I: radial tuberosity of radius and aponeurosis of biceps

A: flex elbow; supinate forearm; flex shoulder

I: musculocutaneous nerve C5, 6

Front 13

Brachialis

Back 13

O: distal half of anterior surface of humerus

I: ulnar tuberosity and coronoid process

A: flex elbow

I: musculocutaneous nerve (small branch of radial nerve) C5, 6

Front 14

Coracobrachialis

Back 14

O: coracoid process

I: medial surface of mid-humeral shaft

A: flex and adduct shoulder

I: musculocutaneous nerve C6, 7

Front 15

Anconeus

Back 15

O: lateral epicondyle of humerus

I: olecranon process of ulna

A: extend elbow

I: radial nerve C7, 8

Front 16

What muscles are part of the rotator cuff?

Back 16

Teres minor, infraspinatus, supraspinatus, and subscapularis

Front 17

Which muscles contribute to shoulder flexion?

Back 17

-Upper fibers of pectoralis major

-Anterior fibers of deltoid

-Biceps brachii

-Coracobrachialis

Front 18

Which muscles contribute to shoulder extension?

Back 18

-Latissimus dorsi

-Teres major

-Lower fibers of pectoralis major

-Posterior fibers of deltoid major

-Long head of triceps brachii

Front 19

Which muscles contribute to shoulder adduction?

Back 19

-Latissimus dorsi

-Pectoralia major

-Teres major

-Teres minor

-Infraspinatus

-Long head of triceps brachii

-Coracobrachialis

Front 20

Which muscles contribute to shoulder abduction?

Back 20

-Deltoid

-Supraspinatus

Front 21

Which muscles contribute to shoulder internal rotation?

Back 21

-Latissimus dorsi

-Teres major

-Subscapularis

-Pectoralis major

-Anterior fibers of deltoid

Front 22

Which muscles contribute to shoulder external rotation?

Back 22

-Teres minor

-Infraspinatus

-Posterior fibers of deltoid

Front 23

Which muscles contribute to shoulder horizontal adduction?

Back 23

-Anterior fibers of deltoid

-Upper fibers of pectoralis major

Front 24

Which muscles contribute to shoulder horizontal abduction?

Back 24

-Posterior fibers of deltoid