Radial Nerve Palsy

Question 1

What is RNP?

Answer 1

Damage to the radial nerve. Most commonly in the upper arm where the radial nerve winds around the humerus and in the extensor muscles of the wrist. Unable to extend wrist also known as wrist drop.

Question 2

What muscles does the radial nerve supply?

Answer 2

Extensors of the wrist: ECU EDM ED EI ECRB ECRL EPL EPB
Supinator
Abductor pollicis longus

Question 3

Dermatomes?

Answer 3

Dorsal aspect of the forearm from elbow down to lateral part of the hand to include thumb to IP joint and fingers to DIP joint (index and middle fingers and sometimes lateral side of ring finer)

Question 4

Seddon classification of nerve injuries

Answer 4

• neuropraxia grade 1 muscle power, gnosis lost. Axon and nerve fibre are intact. Distal conduction maintained no fibrillation
• axonotmesis grade 2-3 all modalities lost. Interruption of axon and distal Wallerian degeneration. Conduction lost; fibrillation
• neurotmesis grade 4-5 all modalities lost. Interruption of the nerve trunk. Wallerian degeneration. Conduction lost; fibrillation

Question 5

How do nerves regenerate?

Answer 5

Neurotmesis requires surgery