Back/Pectoral Region/Rotator Cuffs

Question 1

name the superficial back muscles

Answer 1

trapezius, lattissimus dorsi, levator scapulae + rhomboids (major and minor)

Question 2

which muscles are involved in arm abduction?

Answer 2

supraspinatus (5-15 degrees), deltoid (up to 90), trapezius

Question 3

what is the action and innervation of the trapezius?

Answer 3

accessory nerve.
upper fibres = abduction of arm
middle fibres = retract scapula
lower fibres = pull scapula inferiorly

Question 4

what is the action and innervation of the lattissimus dorsi?

Answer 4

thoracodorsal nerve.

extends, adducts + medially rotates upper limb

Question 5

what is the action and innervation of levator scapulae?

Answer 5

dorsal scapular nerve

elevates scapula

Question 6

what muscle does the thoracodorsal nerve innervate?

Answer 6

lattissimus dorsi

Question 7

what does the dorsal scapular nerve innervate?

Answer 7

levator scapulae and both rhomboids

Question 8

which is superior, rhomboid major or minor?

Answer 8

minor

Question 9

what is the action and innervation of rhomboid major/minor?

Answer 9

dorsal scapular nerve

retracts + rotates scapula

Question 10

which wall of the axilla do the pec major/minor muscles contribute to?

Answer 10

anterior

Question 11

what are the two heads of pectoralis major, and where do they insert to?

Answer 11

clavicular and sternocostal

both insert together in the bicipital groove

Question 12

what is the action and innervation of pectoralis major?

Answer 12

adduct and medially rotate arm (clavicular head also flexes)

medial + lateral pectoral nerves

Question 13

what is the action and innervation of pectoralis minor?

Answer 13

medial pectoral nerve

depresses shoulder

Question 14

to which wall of the axilla does the serratus anterior contribute?

Answer 14

medial

Question 15

what is the action and innervation of serratus anterior?

Answer 15

long thoracic nerve

rotates scapula, allowing arm to be raised over 90 degrees

Question 16

what does the long thoracic nerve supply?

Answer 16

serratus anterior

Question 17

name the 6 intrinsic shoulder muscles?

Answer 17

deltoid + teres major, plus the 4 rotator cuff muscles:

supraspinatus, infraspinatus, subscapularis + teres major

Question 18

what is the action and innervation of the deltoids?

Answer 18

axillary nerve
anterior fibres flex arm @ shoulder
middle fibres - major arm abductor (5-90 degrees)
posterior fibres - extend arm @ shoulder

Question 19

what is the action and innervation of teres major?

Answer 19

lower subscapular nerve

adducts @ shoulder + medially rotates the arm

Question 20

which of teres major/minor is a rotator cuff muscle?

Answer 20

minor

Question 21

what are the 4 rotator cuff muscles?

Answer 21

supraspinatus, infraspinatus, subscapularis + teres minor

Question 22

what is the main action of the rotator cuff muscles?

Answer 22

hold humeral head in the glenoid fossa, stabilising the joint

Question 23

what is the action and innervation of supraspinatus?

Answer 23

suprascapular nerve

abduction 0-5 degrees, and assists deltoids for 5-90 degrees

Question 24

what is the action and innervation of infraspinatus?

Answer 24

suprascapular nerve

lateral rotation of arm

Question 25

which two muscles does the suprascapular nerve innervate?

Answer 25

supraspinatus and infraspinatus

Question 26

what is the action and innervation of subscapularis?

Answer 26

upper and lower subscapular nerve | medially rotates arm

Question 27

what is the action and innervation of teres minor?

Answer 27

axillary nerve | laterally rotates arm