Extensor pollicis brevis 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. The extensor pollicis brevis (EPB) belongs to the deep group of the posterior fascial compartment of the forearm.[1] It is a part of the lateral border of the anatomical snuffbox.

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.)
Originradius and the interosseous membrane
Insertionthumb, proximal phalanx
Arteryposterior interosseous artery
Nerveposterior interosseous nerve
Actionsextension of thumb at metacarpophalangeal joint
AntagonistFlexor pollicis longus muscle, Flexor pollicis brevis muscle
Latinmusculus extensor pollicis brevis
Anatomical terms of muscle


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.


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


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 imagesEdit


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

  1. ^ a b Platzer 2004, p. 168
  2. ^ "Thumb Articulations". ExRx.net.


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

External linksEdit