The origin and innervation of the adductor pollicis muscle.

A gross dissection of twenty human adductor pollicis muscles indicated an extensive origin of both the transverse and oblique heads. The origins included the second, third, and fourth metacarpal bones and the capitate, trapezoid, and trapezium bones. Soft tissue origins included intermetacarpal ligaments and the anterior fascia of palmar interosseous muscles. An interfascicular dissection of the deep branch of the ulnar nerve within the substance of the adductor pollicis muscle revealed three distinct patterns of terminal branching to the transverse and oblique heads, and to the first dorsal interosseous muscle.