Research Article: Isolated Paralysis of the Adductor Pollicis: A Case Report

Date Published: January 27, 2011

Publisher: SAGE-Hindawi Access to Research

Author(s): F. De Maio, S. Bisicchia, P. Farsetti, E. Ippolito.


We report a case of isolated paralysis of the right adductor pollicis in a 30-year-old woman. Electromyographic study showed involvement of the deep motor branch of the ulnar nerve. A ganglion and an anomalous muscle were both ruled out clinically and by MRI as a possible cause of the paralysis. At surgical exploration, we found a fibrous band joining the pisiform and the hook of the hamate bone that compressed the deep motor branch of the ulnar nerve. The fibrous band was excised, and a neurolysis of the motor branch of the ulnar nerve was performed. At followup, eight months later, the patient had fully recovered strength of the adductor muscle.

Partial Text

Both sensory and motor dysfunction as well as a combined dysfunction of the ulnar nerve may be caused by compression of the nerve at Guyon’s canal. Ganglion is the most frequent cause of combined dysfunction and of chronic isolated motor deficit [1]. Other causative factors, like anomalous muscle, occupational pressure neuritis, and variation of the path of the deep motor branch of the ulnar nerve at the wrist, which occur less frequently, have also been described [2–5].

A 30-year-old woman, whose right side was dominant and who worked as a computer operator, presented with a four-month difficulty in performing some activities of daily life with her right hand like writing, holding suspended objects, and turning a key in a lock. In addition she had noticed dorsal prominence of the first metacarpophalangeal joint. No trauma was referred in her recent history.

Compression of the motor branch of the ulnar nerve usually causes weakness and atrophy of the hypothenar muscles and also other muscles such as the interossei, third and fourth lumbricals, adductor pollicis, and part of the flexor pollicis brevis, whereas no sensory impairment is present [7].




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