Abductor pollicis brevis muscle

Muscle infobox
Name = Abductor pollicis brevis muscle
Latin = musculus abductor pollicis brevis
GraySubject = 126
GrayPage = 461


Caption = Abductor pollicis brevis visible at center right.
Origin = Transverse carpal ligament, the scaphoid and trapezium [http://eatonhand.com/mus/mus003.htm Eatonhand - Abductor Pollicis Brevis] ]
Insertion = Radial base of proximal phalanx of thumb and the thumb extensors
Action = 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
Blood =
Nerve = Median nerve
DorlandsPre = m_22
DorlandsSuf = 12548307
The abductor pollicis brevis is a muscle in the hand that functions as an abductor of the thumb.

tructure

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.

Innervation

The abductor pollicis brevis is innervated by the recurrent branch of the median nerve. C8 and T1.

"Note that this is the only muscle of the thenar eminence which is constantly supplied by the median nerve." (Gray's anatomy 39th Ed.)

Actions

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

References

External links

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* [http://www.ptcentral.com/muscles/musclearms.html#abductor%20pollicis%20brevis PTCentral]