Compression of the lateral cutaneous nerve of the forearm: assessment and treatment strategies.

The lateral cutaneous nerve of the forearm (LCNF) is the terminal branch of the musculocutaneous nerve. This purely sensory nerve lies subcutaneously at the level of the antecubital fossa. When the biceps muscle contracts with the elbow in extension, the lateral free edge of the bicipital aponeurosis, which is tensed by forearm pronation, compresses the LCNF. The flat, sharp border of the biceps tendon tightens when the elbow is extended and becomes even tauter when muscle contracts against resisted flexion and pronation. If the forearm is passively pronated with the elbow extended, the nerve is stretched and may be compressed against the biceps tendon. LCNF compression may also be due to trauma, repetitive forearm motion, fascial entrapment, or iatrogenic causes, such as surgical procedures near the elbow. We review the clinical presentation, diagnostic tests and imaging, and treatment options for LCNF compression.