The Medical Latin English adjective for thumb is pollical.

This muscle, the so called pollical palmar interosseous muscle (PPIM), is present in more than 80% of individuals and was first described by .

The capability of a pad-to-pad precision grip in human hands is reflected in the morphology of the distal phalanges, especially in the pollical distal phalanges (PDP).

While the proximal phalanx is curved, the distal pollical phalanx is of human proportions and has thus been associated with toolmaking, but should probably be associated with grasping abilities useful for tree-climbing in this context.

The pollical palmar interosseous (PPIM) is absent in non-human primates and probably is an autapomorphic muscle unique to the human thumb (together with flexor pollicis longus) which probably evolved from the oblique portion of adductor pollicis.