MR-IMAGING OF THE WRIST - NORMAL FINDINGS THAT MAY SIMULATE DISEASE

Twenty-six normal wrists in young adults were studied with magnetic re sonance (MR) imaging, The following conclusions were drawn regarding n ormal anatomic features: (a) Multiple slips of the abductor pollicis l ongus tendon simulate longitudinal tears; (b) the extensor pollicis lo ngus and extensor carpi ulnaris tendons normally demonstrate increased signal intensity simulating tendinitis; (c) small quantities of fluid in the extensor tendon sheaths may be normal and not indicative of te nosynovitis; (d) the triangular fibrocartilage normally demonstrates i ncreased signal intensity simulating tears at its radial and ulnar att achment sites; (e) the volar ulnocarpal ligaments are often indistinct , thereby simulating injury; and (f) the median nerve has signal inten sity equivalent to that of fat, not of muscle as commonly believed. Aw areness of these normal features is critical in making the correct int erpretation of MR images of the wrist.