Radial Nerve

Question 1

aDescribe nerve roots of radial nerve

Answer 1

C5-T1 Nerve Roots

Question 2

Describe the course of the radial nerve

Answer 2

Originates of the posterior cord of the brachial plexus. Exits the axilla through the triangular interval and travels down the posterior aspect of the humorous through the radial groove. It then perices the intramuscular septum to enter the anterior portion of the arm, passing anterior to the lateral epicondyle. It travels through the antecubital fossa before the forearm.

Question 3

Tell me about radial nerve in the forearm

Answer 3

In the forearm the radial nerve dividies into its terminal branches at the levels of the radial head. It gives off its terminal branches, the PIN and the superficial radial nerve.

Question 4

Tell me about the motor function of the radial nerve in the arm.

Answer 4

Supplies posterior aspect of arm including tricep brachii.

Question 5

Tell me about the course and fuctions of the PIN

Answer 5

Motor function to the posterior aspect of the forearm.

At its origin passes between two heads of supinator

Running on beneath the posterior aspect of the interosseous membrane extensor compartment of the arm.

Question 6

Tell me about the course and functions of the Superficial radial nerve

Answer 6

Superficial radial nerve (sensory)

Runs underneath brachioradialis. Lateral to the radial artery

Its terminal branch passes superficial to the tendons of the anatomical snuff box

Supplies:

Dorsal aspect of 1st interossei

Dorsal aspect of radial 3.5 digits (excluding nail beds)

Question 7

How would you quickly test for a radial nerve lesion

Answer 7

Ask patient to extend wrist and fingers.

Test sensation over the first dorsal webspace.

Question 8

How would you differentiate between a high a low radial nerve lesion?

Answer 8

Damage at axilla - Loss of extension at the elbow, wrist and finger extension

Damage at radial groove - Loss of wrist and finger extension

Damage at the radial head - Dislocation or fracture of radial head.

• Wrist drop may not fully occur if PIN is damaged, this is because radial nerve proper still has an effect of ECRL&ECRB.

Reteropulsion of thumb for PIN - EPL.

Superficial radial nerve - (Laceration)

Sensation over the dorsum of the hand.

Question 9

What are the branches and innervation of the radial nerve?

Answer 9

Radial nerve proper -
ECRB
ECRL
Anconeus
Brachioradialis

PIN (Deep Branches)
ED
supinator
EDM
ECU
APL
EPL
EPB
EIP