Negative Phalen's test Weakness of the median innervated muscles is rare. Provocative tests Resisted pronation of the forearm for 30 to 60 seconds demonstrates compression at pronator teres when symptoms are reproduced. Resisted elbow flexion and supination of the forearm can localize compression to the lacertus fibrosis. The supracondylar process can be palpated on the medial humeral surface and confirmed with radiographs. Flexor pollicis longus innervated by anterior interosseus nerve.
Diagnosis is made clinically.
Associated with activities that require forceful grasp coupled with ulnar deviation or repetitive use of the thumb. Those at risk include golfers, fly fishers, racquet sport players, knitters, laboratory technicians, filing clerks, and mail sorters. Tenosynovitis develops in the APL and EPB tendons that are held in a groove of the radius by a firm segment of the extensor retinaculum. Pain in the radial aspect of the wrist and thumb, aggravated by movement of the wrist and thumb. If inflammation is severe, the dorsal sensory branch of the radial nerve can become irritated, and patients complain of pain and paresthesias radiating to the thumb, dorsum of the hand, and index finger.