Radial nerve

Question 1

The radial nerve is a continuation of which cord of the brachial plexus?

Answer 1

posterior cord of the brachial plexus (root values C5 to T1)

Question 2

Describe the path taken by the radial nerve

Answer 2

Lies posterior to the axillary artery on subscapularis, latissimus dorsi and teres major.

Enters the arm between the brachial artery and the long head of triceps (medial to humerus).

Spirals around the posterior surface of the humerus in the groove for the radial nerve.

At the distal third of the lateral border of the humerus it then pierces the intermuscular septum and descends in front of the lateral epicondyle.

At the lateral epicondyle it lies deeply between brachialis and brachioradialis where it then divides into a superficial and deep terminal branch.

Deep branch crosses the supinator to become the posterior interosseous nerve.

Question 3

Muscles innervated by the radial nerve

Answer 3

Triceps
Anconeus
Brachioradialis
Extensor carpi radialis

Question 4

Muscles innervated by the posterior interosseous branch of the radial nerve

Answer 4

Supinator
Extensor carpi ulnaris
Extensor digitorum
Extensor indicis
Extensor digiti minimi
Extensor pollicis longus and brevis
Abductor pollicis longus

Question 5

what area has sensory supply from the radial nerve?

Answer 5

proximal phalanges on the dorsal aspect of the hand is supplied by the radial nerve
(not including ring/pinky fingers)

Question 6

Describe the effect of paralysis of Long head of triceps

Answer 6

Minor effects on shoulder stability in abduction

Question 7

Describe the effect of paralysis of triceps

Answer 7

Loss of elbow extension

Question 8

Describe what would happen in paralysis of Supinator,
Brachioradialis, Extensor carpi radialis longus and brevis

Answer 8

Weakening of supination of prone hand and elbow flexion in mid prone position