Forearm nerve entrapment syndromes (AIN, PIN, radial nerve palsy)

What it is

Three named nerve lesions, each read off the muscles that its nerve supplies.

The AIN innervates the flexor digitorum profundus to digits 2 and 3, the flexor pollicis longus, and the pronator quadratus.

Posterior interosseous nerve entrapment comes in two types, after Spinner. In type I there is complete paralysis of all the muscles supplied by the nerve: extensor digitorum communis, extensor indicis proprius, extensor digiti quinti, extensor carpi ulnaris, abductor pollicis longus and extensor pollicis brevis. In type II only one or a few of these muscles are paralyzed.

Radial nerve palsy is also called Saturday night palsy.