Neuropathy of motor branch of median or ulnar nerve induced by midpalm ganglion

Two cases of neuropathy of a motor branch caused by a midpalmal ganglion ar e presented. In the first case the ganglion originated from the midcarpal j oint, protruded into the thenar muscle, and compressed the motor branch of the median nerve. In the second case the ganglion, distal to the fibrous ar ch of the hypothenar muscles, originated from the third carpometacarpal joi nt and compressed the motor branch of the ulnar nerve. In both cases muscle weakness and finger deformity recovered well after resection of the gangli on. This clinical condition is rare compared with carpal tunnel syndrome an d Guyon's tunnel syndrome, which are caused by a ganglion in the wrist. Cop yright (C) 2001 by the American Society for Surgery of the Hand.