Adductor pollicis muscle

The adductor pollicis muscle is a muscle of the hand that adducts the thumb when contracted (pulls it inward toward the first finger).

Origin
The adductor pollicis muscle originates from several points in the hand. The oblique head attaches at the base of the second and third metacarpals, the trapezoid bone and the capitate bone. The transverse head originates from the shaft of the third metacarpal bone.

Insertion
The adductor pollicis muscle inserts on the thumb at the base of the proximal phalanx. It also attaches to the tendon of the extensor pollicis longus muscle and the ulnar sesamoid.

Action
The adductor pollicis muscle adducts the thumb at the carpometacarpal joint.

Innervation
The adductor pollicis muscle is innervated by the deep branch of the ulnar nerve (T1).

Word origin
The adductor pollicis gets its name from its action: adductor refers to its action as an adductor, and pollicis means of the thumb.