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Abductor pollicis brevis muscle

Origins, insertions, innervation and function of the abductor pollicis brevis muscle.

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Hey there! It’s Matt from Kenhub, and in this tutorial, we will be discussing the abductor pollicis brevis muscle. The thenar musculature consists of four muscles located on the radial side of the palm. Together, they form the ball of the thumb known as the thenar eminence. They originate at different carpal bones and distally attach to the thumb. As mentioned before, the focus of this tutorial will be the abductor pollicis brevis which is one of the thenar muscles.

The abductor pollicis brevis muscle arises from the tubercles of the scaphoid and, in some cases, the trapezium and form the flexor retinaculum. The abductor pollicis brevis’ short tendon courses to the base of the proximal phalanx and the dorsal aponeurosis of the thumb via the radial sesamoid bone. The abductor pollicis brevis lies quite superficially underneath the skin.

The recurrent or thenar branch of the median nerve is responsible for the innervation of the abductor pollicis brevis. The main function of each thenar muscle is associated to their names. The abductor pollicis brevis moves the thumb away from the hand also referred to as abduction at the carpometacarpal joint. This muscle is also able to perform flexion of the thumb. Since the abductor pollicis brevis, adductor pollicis, and flexor pollicis brevis attach more distally at the thumb, they can also perform extension at the interphalangeal joint.

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