Opponens pollicis

The opponens pollicis (Latin: musculus opponens pollicis) is a short intrinsic muscle of the hand. It is located on the lateral (radial) side of the palm and participates in forming the thenar eminence. Therefore, together with the flexor pollicis brevis, adductor pollicis and abductor pollicis brevis, the opponens pollicis is also known as one of the four thenar muscles. The opponens pollicis extends between the trapezium (carpal bone) and the first metacarpal bone. It lies inferior to the abductor pollicis brevis and lateral to the flexor pollicis brevis muscle.

Origin

The opponens pollicis muscle originates from the flexor retinaculum and trapezium bone.

Insertion

The opponens pollicis inserts on the base of the first metacarpal bone.

Action

The opponens pollicis muscle provides the opposition of the thumb at the first carpometacarpal joint.

Innervation

The opponens pollicis is innervated by the recurrent branch of the median nerve (C8, T1) and the deep terminal branch of the ulnar nerve (C8, T1).

Blood supply

The opponens pollicis muscle receives arterial blood supply from the superficial palmar arch that is mainly formed by the radial artery.