Which physical findings are characteristic of radial mononeuropathy?

Updated: Jun 14, 2018
  • Author: Wayne E Anderson, DO, FAHS, FAAN; Chief Editor: Nicholas Lorenzo, MD, MHA, CPE  more...
  • Print

Radial neuropathy typically presents with weakness of wrist dorsiflexion (ie, wrist drop) and finger extension.

  • If the lesion is in the axilla, all radial-innervated muscles are involved.

    • The triceps and brachioradialis reflexes are decreased.

    • Sensation is decreased occur over the triceps, the posterior part of the forearm, and dorsum of the hand.

  • 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.

    • Triceps reflex is preserved, but brachioradialis is decreased.

    • Sensory loss is over the radial dorsal part of the hand and the posterior part of the 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.

    • Brachioradialis reflex is intact.

    • The extensor carpi radialis sometimes is 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. Numbness of the dorsal hand is noted, sparing the fifth digit.

Did this answer your question?
Additional feedback? (Optional)
Thank you for your feedback!