Pectoral girdle and shoulder 2: rotator cuff

Question 1

what is the rotator cuff

Answer 1

group of 4 muscles that help keep head of humerus in the glenoid cavity of scapula

Question 2

the rotator cuff surrounds the joint capsule except where

Answer 2

at most inferior aspect where a small gap remains

Question 3

what is the most common direction to dislocate the shoulder

Answer 3

towards gap in an antero-inferior direction

Question 4

what are the 4 muscles of the rotator cuff

Answer 4

subscapularis
supraspinatus
infraspinatus
teres minor

Question 5

which of the rotator cuff muscles is considered the odd one out

Answer 5

subscapularis

Question 6

what are the attachments of subscapularis

Answer 6

subscapular fossa on anterior surface of scapula to lesser tubercle of humerus

Question 7

what is the innervation of subscapularis

Answer 7

upper and lower subscapular nerves (C5,6,7) from posterior cord of brachial plexus

Question 8

what does subscapularis do

Answer 8

medially rotates arm and reinforces anterior surface of capsule

Question 9

why is subscapularis the odd one out

Answer 9

• lies on anterior surface (others are posterior)
• attaches to the lesser tubercle (others are greater)
• medially rotates the arm (2 of the others laterally rotate)

Question 10

what are the attachments of supraspinatus

Answer 10

supraspinous fossa of scapula (posterior) to greater tubercle of humerus (upper facet)

Question 11

supraspinatus passes over the ____ surface of the joint

Answer 11

lateral

Question 12

action of supraspinatus

Answer 12

abducts arm first 10-15 degrees

Question 13

what is the innervation of supraspinatus

Answer 13

suprascapular nerve (C5,6) from superior trunk of brachial plexus

Question 14

what can happen if the tendon of supraspinatus becomes inflamed

Answer 14

it can become entrapped in small space near humerus that is passes through

Question 15

what are the attachments of infraspinatus

Answer 15

infraspinous fossa of scapula (posterior) to greater tubercle of humerus (middle facet)

Question 16

what is the action of infraspinatus

Answer 16

lateral rotation of arm

Question 17

what is the innervation of infraspinatus

Answer 17

suprascapular nerve (C5,6) from superior trunk of brachial plexus

Question 18

the suprascapular nerve (C5,6) innervates what muscles of the rotator cuff

Answer 18

infraspinatus

supraspinatus

Question 19

what muscle attaches to the upper facet of the greater tubercle of the humerus

Answer 19

supraspinatus

Question 20

what muscle attaches to the middle facet of the greater tubercle of humerus

Answer 20

infraspinatus

Question 21

what muscle attaches to the lower facet of the greater tubercle of humerus

Answer 21

teres minor

Question 22

what are the attachments of teres minor

Answer 22

upper 2/3 lateral border of scapula to greater tubercle of humerus (lower faet)

Question 23

what is the innervation of teres minor

Answer 23

axillary nerve (C5,6) branch of posterior cord of brachial plexus

Question 24

what is the function of teres minor

Answer 24

lateral rotation of arm

Question 25

teres minor attaches to the lateral border of the scapula between what 2 muscles

Answer 25

long head triceps and teres major

Question 26

what 2 muscles of the rotator cuff are lateral rotators of the arm

Answer 26

teres minor and infraspinatus

Question 27

what is the innervation of the rotator cuff

Answer 27

subscapularis - subscapular nerve
supraspinatus - suprascapular nerve
infraspinatus - suprascapular nerve
teres minor - axillary nerve