Finger flexion sign for ulnar neuropathy.

ABSTRACT

We report a diagnostic sign of ulnar neuropathy. Function of the interossei is tested by asking the patient to hold a sheet of paper between the middle and ring fingers, by adducting the fingers while the examiner pulls it firmly away. The metacarpophalangeal joints will flex more on the affected side as the flexor tendons are recruited. This test can easily detect muscle weakness in the early stage of ulnar neuropathy, and is produced by a similar mechanism to that of Froment's sign.