This presentation is initially acute for several days to weeks. If the lesion is at the wrist, then sensory changes and paresthesias over the back of the hand are the most common complaints. If the lesion is high in the axilla, all radial innervated muscles are involved. Acute compression of the radial nerve commonly occurs at the spiral groove. If the lesion is at this level, all radial innervated muscles distal to the triceps are weak.
Sensory loss is over the radial dorsal hand and posterior forearm.
Numbness over the triceps area is variable. In isolated posterior interosseous lesions, sensation is spared and motor involvement occurs in radial muscles distal to the supinator. The extensor carpi radialis is sometimes also spared, resulting in radial deviation with wrist extension. Pain may occur with palpation at the proximal forearm and with forceful supination. In distal radial sensory lesions at the wrist, no motor weakness occurs.