Additional heads of dorsal interosseous muscle in Caucasian cadavers and their clinical significance

Dorsal interossei are group of four intrinsic muscles of the hand that are of immense importance in its day-to-day functions. The finding of any variation related to these muscles is of significance from point of view of hand surgeons. In the present article, we report additional heads of dorsal interosseous muscle (DIM) in four upper limbs of a male cadavers. The muscles took origin from the dorsal surface of the adjacent metacarpal bones as well as from the distal row of carpal bones, had a belly separate from the two pennae of the DIM, distally joining the tendon of corresponding DIM. We discuss the anatomical details and clinical implications of this variation.