Muscles of the Shoulder

Question 1

Attachments of deltoid

Answer 1

O: anterior fibres - anterior border lateral 1/3rd clavicle , middle fibres - outer margins of acromion, posterior fibres - lower border of spine of scapula

I: deltoid tuberosity of humerus

Question 2

Nerve supply of deltoid

Answer 2

Axillary nerve - C5, 6

Question 3

Action of deltoid

Answer 3

Abduct the arm

Anterior fibres - flex and medially rotate

Posterior fibres - extend and laterally rotate

Question 4

Function of deltoid

Answer 4

carrying bags

Question 5

Attachments: Subscapularis

Answer 5

O: medial 2/3rd subscapular fossa

I: lesser tubercle of humerus & the capsule

Question 6

Action of subscapularis

Answer 6

Strong medial rotator

Assists Adduction

Holds humeral head in glenoid fossa

Question 7

Function of subscapularis

Answer 7

Scratching back

Question 8

Nerve supply: Subscapularis

Answer 8

upper and lower subscapular nerves C5,6,7

Question 9

Attachments: Supraspinatus

Answer 9

O: medial 2/3rds supraspinous fossa

I: deep surface blends with JC, then inserts to UPPER facet of GREATER tubercle

Question 10

Nerve supply: Supraspinatus

Answer 10

Suprascapular nerve (C5, 6)

Question 11

Action of supraspinatus

Answer 11

Initiation of abduction Braces humeral head in glenoid fossa

Question 12

function of supraspinatus

Answer 12

side reaching

Question 13

Attachments of Teres Minor

Answer 13

O: upper 2/3rd of lateral border of scapula

I: inferior facet on greater tubercle of humerus

Question 14

Nerve supply: Teres Minor

Answer 14

Axillary Nerve

C5, 6

Question 15

Action of teres minor

Answer 15

Reinforces lower JC

Lateral rotation - in anatomical position

In abduction - Lateral rotation and adduction

Question 16

Function of teres minor

Answer 16

brushing hair

Question 17

Attachments of infraspinatus

Answer 17

O: medial 2/3rds infraspinous fossa

I: middle fact on greater tubercle of humerus and posterior JC

Question 18

Nerve supply of infraspinatus

Answer 18

suprascapular nerve C5, 6

Question 19

Action of infraspinatus

Answer 19

lateral rotation

Question 20

function of infraspinatus

Answer 20

brushing hair

Question 21

Attachments of serratus anterior

Answer 21

O: outer surfaces of upper 8 or 9 ribs and intercostal fascia

I: costal surface of medial border of scapula

Question 22

Nerve supply of serratus anterior

Answer 22

long thoracic nerve C5, 6, 7

Question 23

action of serratus anterior

Answer 23

protraction and lateral rotation of the scapula

Question 24

function of serratus anterior

Answer 24

punching

Question 25

attachments of pectoralis major

Answer 25

O: medial 1/2 anterior border of clavicle, anterior surface of clavicle and anterior surface of upper 6 CCs, 6th rib I: lateral lip of bicipital groove

Question 26

Nerve supply of pectoralis major

Answer 26

medial and lateral pectoral nerves C5-T1

Question 27

Action of pectoralis major

Answer 27

flexes, medially rotates and addicts the arm

Question 28

function of pectoralis major

Answer 28

punching

Question 29

attachments of coracobrachialis

Answer 29

O: apex of coracoid process I: medial side of shaft of humerus

Question 30

nerve supply to coracobrachialis

Answer 30

musculocutaneous nerve C6 and C7

Question 31

action of coracobrachialis

Answer 31

adducts and flexes the arm

Question 32

function of coracobrachialis

Answer 32

gripping object to trunk

Question 33

attachments of lattisimus dorsi

Answer 33

O: - via thoracolumbar fascia to spinous processes of T7-12, - all lumbar and sacral vertebrae, - supraspinous and interspinous ligaments, - posterior outer lip of iliac crest, - lower 4 ribs - inferior angle of scapula I: via long flat tendon with 180 degree twist to floor of bicipital groove of humerus

Question 34

Nerve supply of lattisimus dorsi

Answer 34

thoracodorsal nerve C6, 7, 8

Question 35

Action of lattisimus dorsi

Answer 35

adducts, medially rotates and extends the arms

Question 36

function of lattisimus dorsi

Answer 36

pushing up out of a chair

Question 37

attachments of teres major

Answer 37

O: lower third lateral border and inferior angle of scapula I: medial lip of intertubecular groove of humerus

Question 38

nerve supple of teres major

Answer 38

lower subscapular nerve C6, 7

Question 39

action of teres major

Answer 39

adducts and medial rotation

Question 40

function of teres major

Answer 40

scratching back