Muscles of the shoulder

Question 1

What two classifications can the shoulders muscles be divided into?

Answer 1

extrinsic- originate from torso and attach to the bones of the shoulder (clavicle, scapula, humerus)
intrinsic- originate from the scapula and/or clavicle and attach to the humerus

Question 2

what are the two superficial muscles?

Answer 2

trapezius and latissimus dorsi

Question 3

origin of the trapezius

Answer 3

skull, nuchal ligament and spinous processes of C7-T12

Question 4

insertion of trapezius

Answer 4

clavicle, acromion and scapula spine

Question 5

innervation of the trapezius

Answer 5

accessory nerve (motor)
proprioceptor fibres from C3 and C4 spinal nerves

Question 6

functions of the trapezius

Answer 6

upper fibres of trapezius- elevate scapula and rotate it during abduction
middle fibres of trapezius- retract the scapula
lower fibres of trapezius- pull the scapula inferiorly

Question 7

origin of latissimus dorsi

Answer 7

T7-T12, iliac crest, thoracolumbar fascia and 3 pairs of inferior ribs

Question 8

insertion of latissimus dorsi

Answer 8

intertubercular sulcus of the humerus

Question 9

innervation of latissimus dorsi

Answer 9

thoracodorsal nerve

Question 10

functions of the latissimus dorsi

Answer 10

extends, adducts and medially rotates the upper limbs

Question 11

What are the three deep muscles?

Answer 11

levator scapulae, x2 rhomboids

Question 12

origin of the levator scapulae

Answer 12

transverse process of C1-C4

Question 13

insertion of the levator scapulae

Answer 13

medial border of the scapula

Question 14

innervation of the levator scapulae

Answer 14

dorsal scapular nerve

Question 15

functions of the levator scapulae

Answer 15

elevates the scapula

Question 16

What are the two rhomboid muscles called?

Answer 16

rhomboid minor and rhomboid major (rhomboid minor is superior to rhomboid major)

Question 17

origin of rhomboid major

Answer 17

spinous processes of T2-T5

Question 18

insertion of rhomboid major

Answer 18

medial border of the scapula (between scapula spine and inferior angle)

Question 19

innervation of rhomboid major

Answer 19

dorsal scapular nerve

Question 20

functions of the rhomboid major

Answer 20

retracts and rotates the scapula

Question 21

origin of the rhomboid minor

Answer 21

spinous processes C7-T1

Question 22

insertion of the rhomboid minor

Answer 22

medial border of the scapula (level of the scapula spine)

Question 23

innervation of the rhomboid major

Answer 23

dorsal scapular nerve

Question 24

functions of the rhomboid major

Answer 24

retracts and rotates the scapula

Question 25

What are the 6 intrinsic muscles of the shoulder region?

Answer 25

deltoid, teres major and the 4 rotator cuff muscles

Question 26

origin of the deltoid

Answer 26

clavicle (lateral third), acromion and spine of the scapula

Question 27

insertion of the deltoid muscle

Answer 27

deltoid tuberosity on the humerus

Question 28

innervation of the deltoid muscle

Answer 28

axillary nerve

Question 29

functions of the deltoid muscle

Answer 29

anterior fibres- flexion and medial rotation
posterior fibres- extension and lateral rotation
middle fibres- major abductor of the arm

Question 30

origin of the teres major

Answer 30

posterior surface of the inferior angle of the SCAPULA

Question 31

insertion of the teres major

Answer 31

medial lip of the intertubercular groove of the humerus

Question 32

innervation of the teres major

Answer 32

lower sub scapular nerve

Question 33

functions of the teres major

Answer 33

adducts and extends at the shoulder

medially rotates the arm

Question 34

what are the four rotator cuff muscles?

Answer 34

supraspinatus, infrapsinatus, subscapularis and teres minor

Question 35

What is the collective function of the rotator cuff muscles?

Answer 35

(collectively originate from the scapula and insert into the humeral head)
The muscles ‘pull’ the humeral head into the glenoid fossa. This gives the glenohumeral joint a lot of additional stability.

Question 36

origin of the supraspinatus

Answer 36

supraspinous fossa of the scapula

Question 37

insertion of the scapula

Answer 37

greater tubercle of the humerus

Question 38

function of the supraspinatus

Answer 38

abducts the arm 0-15 degrees

assists deltoid for 15-90 degrees

Question 39

origin of the infraspinatus

Answer 39

infraspinous fossa of the scapula

Question 40

insertion of the infraspinatus

Answer 40

greater tubercle of the humerus

Question 41

what is the innervation of the supraspinatus and infraspinatus

Answer 41

suprascapular nerve

Question 42

function of the infraspinatus

Answer 42

laterally rotates the arm

Question 43

origin of the subscapularis

Answer 43

subscapular fossa

Question 44

insertion of the subscapularis

Answer 44

lesser tubercle of the humerus

Question 45

innervation of the subscapularis

Answer 45

upper and lower sub scapular nerves

Question 46

function of the subscapularis

Answer 46

medially rotates the arm

Question 47

origin of the teres minor

Answer 47

posterior surface of the scapula

Question 48

insertion of the teres minor

Answer 48

greater tubercle of the humerus

Question 49

innervation of the teres minor

Answer 49

axillary nerve

Question 50

function of the teres minor

Answer 50

laterally rotates the arm