Extensor pollicis brevis muscle

Extensor pollicis brevis muscle
Front of right upper extremity. (Extensor pollicis brevis labeled at upper left.)
Posterior surface of the forearm. Deep muscles. (Extensor pollicis brevis visible at left.)
Details
Origin radius and the interosseous membrane
Insertion thumb, proximal phalanx
Artery posterior interosseous artery
Nerve posterior interosseous nerve
Actions extension of thumb at metacarpophalangeal joint
Antagonist Flexor pollicis longus muscle, Flexor pollicis brevis muscle
Identifiers
Latin musculus extensor pollicis brevis
TA A04.6.02.050
FMA 38518
Anatomical terms of muscle

In human anatomy, the extensor pollicis brevis is a skeletal muscle on the dorsal side of the forearm. It lies on the medial side of, and is closely connected with, the abductor pollicis longus.

Structure

The extensor pollicis brevis arises from the ulna distal to the abductor pollicis longus, from the interosseous membrane, and from the dorsal surface of the radius. [1]

Its direction is similar to that of the abductor pollicis longus, its tendon passing the same groove on the lateral side of the lower end of the radius, to be inserted into the base of the first phalanx of the thumb.

Variation

Absence; fusion of tendon with that of the extensor pollicis longus.

Function

In a close relationship to the abductor pollicis longus, the extensor pollicis brevis both extends and abducts the thumb[1] at the carpometacarpal and metacarpophalangeal joints.[2]

Additional images

References

This article incorporates text in the public domain from page 455 of the 20th edition of Gray's Anatomy (1918)

  1. 1 2 Platzer 2004, p. 168
  2. ↑ "Thumb Articulations". ExRx.net. Retrieved June 2010. Check date values in: |accessdate= (help)

Sources

  • Platzer, Werner (2004). Color Atlas of Human Anatomy, Vol. 1: Locomotor System (5th ed.). Thieme. ISBN 3-13-533305-1.
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