Abductor pollicis brevis muscle
Abductor pollicis brevis visible at center right.
Latin	musculus abductor pollicis brevis
Gray's	subject #126 461
Origin	Transverse carpal ligament, the scaphoid and trapezium [1]
Insertion	Radial base of proximal phalanx of thumb and the thumb extensors [1]
Artery	Superficial palmar arch
Nerve	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

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

Contents 1 Structure 2 Innervation 3 Actions 4 Additional images 5 References 6 External links

[edit] 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.

[edit] Innervation

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

[edit] 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.

[edit] Additional images

Nerves of the left upper extremity.

[edit] References

1. ^ ^{a b} Eatonhand - Abductor Pollicis Brevis

[edit] External links

• LUC abpb
• 772145152 at GPnotebook
• PTCentral

This article was originally based on an entry from a public domain edition of Gray's Anatomy. As such, some of the information contained within it may be outdated.

v • d • e List of muscles of upper limbs (TA A04.6, GA 4.432) Shoulder deltoid · rotator cuff (supraspinatus, infraspinatus, teres minor, subscapularis) · teres major fascia: Deltoid fascia · Supraspinous fascia · Infraspinous fascia Arm (compartments) Anterior coracobrachialis · biceps brachii · brachialis Posterior triceps brachii · anconeus · Articularis cubiti Fascia Axillary sheath · Axillary fascia · Brachial fascia · intermuscular septa (Lateral, Medial) Other spaces (Quadrangular space, Triangular space, Triangular interval) Forearm Anterior superficial: pronator teres · palmaris longus · flexor carpi radialis · flexor carpi ulnaris · flexor digitorum superficialis deep: pronator quadratus · flexor digitorum profundus · flexor pollicis longus Posterior superficial: mobile wad (brachioradialis, extensor carpi radialis longus and brevis) · extensor digitorum · extensor digiti minimi · extensor carpi ulnaris deep: supinator · anatomical snuff box (abductor pollicis longus, extensor pollicis brevis, extensor pollicis longus) · extensor indicis Fascia Bicipital aponeurosis · common tendons (Extensor, Flexor) · Antebrachial fascia Other Cubital tunnel Hand Lateral volar thenar (opponens pollicis, flexor pollicis brevis, abductor pollicis brevis) · adductor pollicis Medial volar hypothenar (opponens digiti minimi, flexor digiti minimi brevis, abductor minimi digiti) · palmaris brevis Intermediate lumbrical · interossei (dorsal, palmar) Fascia posterior: Extensor retinaculum · Extensor expansion anterior: Flexor retinaculum · Palmar aponeurosis

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