Dissection 11: Shoulder Joint, Posterior Arm and Posterior Forearm

Question 1

what nerve supplies the posterior compartment arm muscles?

Answer 1

deep branch of the radial nerve

Question 2

arterial supply to the posterior compartment of the arm?

Answer 2

posterior interosseous artery

Question 3

what is the posterior interosseous artery a branch of?

Answer 3

ulnar artery

Question 4

what nerve supplies the deltoid muscle?

Answer 4

axillary

Question 5

origin of the deltoid muscle

Answer 5

lateral 1/3rd of clavicle and inferior scapular spine and acromion

Question 6

insertion of deltoid muscle?

Answer 6

deltoid tuberosity of humerus

Question 7

what do the rotator cuff muscles do?

Answer 7

strengthen the fibrous capsule of the shoulder joint superiorly and posteriorly

Question 8

sensory innervation to the posteromedial aspect of the arm

Answer 8

anterior rami of C8, T1, T2

Question 9

what is the significance of the posteromedial arm’s sensory innervation in terms of pain?

Answer 9

cardiac pain refers here as it also is supplied by C8, T1, T2

Question 10

sensory innervation to the posterolateral aspect of the arm

Answer 10

anterior rami of C5 and 6 via axillary nerve

Question 11

innervation of triceps brachii?

Answer 11

radial nerve

Question 12

only muscle of the posterior compartment of the arm?

Answer 12

triceps brachii

Question 13

insertion of the long head of the triceps brachii?

Answer 13

infraglenoid tubercle of the scapula

Question 14

insertion of the lateral head of the triceps brachii?

Answer 14

superior to the radial groove of the humerus

Question 15

insertion of the medial head of the triceps brachii?

Answer 15

inferior to the radial groove of the humerus

Question 16

function of the triceps brachii?

Answer 16

extension of the forearm at the elbow eg lifting bean cans

Question 17

what is the space called that the axillary nerve found in?

Answer 17

quadrangular space

Question 18

superior border of the axillary nerve’s quadrangular space?

Answer 18

teres minor

Question 19

inferior border of the axillary nerve’s quadrangular space?

Answer 19

teres major

Question 20

medial border of the axillary nerve’s quadrangular space?

Answer 20

long head of triceps

Question 21

lateral border of the axillary nerve’s quadrangular space?

Answer 21

humerus

Question 22

what is the “badge patch” ?

Answer 22

area of skin supplied by the axillary nerve

Question 23

how can you test the axillary nerve?

Answer 23

ask patient to abduct upper limb beyond 15 degrees

Question 24

where does the radial nerve originate?

Answer 24

axilla

Question 25

where is the radial nerve found?

Answer 25

radial groove of humerus

Question 26

where do the muscles of the superficial layer of the posterior forearm originate

Answer 26

common extensor tendon on lateral epicondyle of humerus

Question 27

where do the muscles of the deep layer of the posterior forearm originate

Answer 27

shafts of radius and ulna | interosseus membrane

Question 28

what structure holds tendons in place as they cross the wrist?

Answer 28

extensor retinaculum

Question 29

why is the brachioradialis not considered to be a muscle of the posterior compartment of the forearm?

Answer 29

its in the boundary of anterior and posterior

Question 30

main function of the brachioradialis

Answer 30

flexion of the semi pronate forearm eg drinking

Question 31

when does the radial nerve divide?

Answer 31

just anterior to the lateral epicondyle

Question 32

what does the deep branch of the radial nerve supply?

Answer 32

supinator

Question 33

when does the deep branch of the radial nerve change its name? what does it become?

Answer 33

after supplying the supinator; posterior interosseous nerve