The Posterior Compartment of the Arm

Question 1

which muscle occupies the entire posterior compartment of the arm?

Answer 1

triceps

Question 2

what is the origin and insertion of the triceps?

Answer 2

• it arises by a long head from the scapula and by two shorter heads; the lateral and medial heads, from the humerus.
• the common tendon of triceps is inserted into olecranon process of the ulna.

Question 3

extend you arm straight and feel the back of the elbow - the ‘bump’ at the back is called the?

Answer 3

olecranon process of the ulna

Question 4

which head of the triceps attaches onto the infra-glenoid tuberclue of the scapula?

Answer 4

long head of triceps

Question 5

what is the main action of triceps on the elbow joint?

Answer 5

extension of elbow

Question 6

what is the aconeus?

Answer 6

a small muscle at the elbow that aids the triceps muscle action at the elbow joint > extension

Question 7

what is the nerve supply to the triceps and aconeus?

Answer 7

radial nerve

Question 8

which nerve innervates all the extensor muscles of the elbow and wrist joint?

Answer 8

radial nerve

Question 9

the radial nerve is one of the terminal branches of which cord of the brachial plexus?

Answer 9

posterior cord

Question 10

Answer 10

Question 11

what is the segmental (root) value of the radial nerve?

Answer 11

C5-T1

Question 12

what is the characteristic sign of radial nerve injury?

Answer 12

wrist drop

Question 13

Answer 13

• 1c
• 2b
• 3a