Radial nerve entrapment.

The radial nerve is frequently more involved in entrapment syndromes than the ulnar and median nerves. Common sites of compression are the juncture of the middle and distal third of the arm (especially with fractures of the humerus), just distal to the elbow (radial tunnel), and proximal to the wrist between the brachioradialis and extensor carpi radialis longus. Often in entrapment syndromes involving the radial nerve, the true diagnosis is not evident and is arrived at only by exclusion, which sometimes delays initiation of effective treatment. Radial tunnel syndrome is rare, but decompression when indicated, can provide relief. Radial sensory nerve entrapment in the forearm (distal third) does occur, but patients often respond to temporary thumb spica splinting.