Abductor pollicis brevis muscle
Superficial muscles of the left hand, palmar view
Details
Origin	Transverse carpal ligament, the scaphoid and trapezium[1]
Insertion	base of the proximal phalanx of thumb
Artery	Superficial palmar arch
Nerve	Recurrent branch of the median nerve
Actions	Abduction of the thumb by acting across the carpometacarpal joint and the metacarpophalangeal joint. It also assists in opposition and extension of the thumb.
Antagonist	Adductor pollicis muscle
Identifiers
Latin	musculus abductor pollicis brevis
TA98	A04.6.02.054
TA2	2521
FMA	37373
Anatomical terms of muscle

The abductor pollicis brevis is a muscle in the hand that functions as an abductor of the thumb.

Structure

The abductor pollicis brevis is a flat, thin muscle located just under the skin. It is a thenar muscle, and therefore contributes to the bulk of the palm's thenar eminence.

It originates from the flexor retinaculum of the hand, the tubercle of the scaphoid bone, and additionally sometimes from the tubercle of the trapezium.

Running lateralward and downward, it is inserted by a thin, flat tendon into the lateral side of the base of the first phalanx of the thumb, and the capsule of the metacarpophalangeal joint.

Function

Abduction of the thumb is defined as the movement of the thumb anteriorly, a direction perpendicular to the palm. The abductor pollicis brevis does this by acting across both the carpometacarpal joint and the metacarpophalangeal joint.

It also assists in opposition and extension of the thumb.

Additional images

• 
  Cadaver dissection

References

This article incorporates text in the public domain from page 461 of the 20th edition of Gray's Anatomy (1918)