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Extensor pollicis brevis

The extensor pollicis brevis (Latin: musculus extensor pollicis brevis) is a flat, thin and relatively short muscle of the forearm that extends between the radius and the proximal phalanx of the thumb. It belongs to the posterior compartment of the forearm muscles, and it lies in the second layer.

Extensor pollicis brevis
Origin Posterior surface of distal radius, interosseous membrane of forearm
InsertionBase of proximal phalanx of 1st finger
ActionThumb extension
InnervationPosterior interosseous nerve of radial nerve (C7, C8)
Blood supply Anterior and posterior interosseous arteries
Forearm muscles (colored), Upper extremity, Muscles, Human arm, Anteromedial view, Dorsolateral view
Muscles of forearm by Anatomy.app

 

Origin

The extensor pollicis brevis muscle originates from the posterior surface of the distal radius and interosseous membrane of the forearm.

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Origin and insertion of extensor pollicis brevis by Anatomy.app

 

Insertion

The extensor pollicis brevis inserts on the base of the proximal phalanx of the first finger.

Extensor pollicis brevis, Forearm muscles, Muscles of forearm, Posterior compartment muscles, Posterior compartment of forearm muscles, Human hand, Forearm extensors
Extensor pollicis brevis by Anatomy.app

 

Action

The extensor pollicis brevis muscle extends the thumb at the first carpometacarpal and metacarpophalangeal joints.

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Action of extensor pollicis brevis by Anatomy.app

 

Innervation

The extensor pollicis brevis is innervated by the posterior interosseous branch of the radial nerve (C7, C8). The radial nerve arises from the brachial plexus.

 

Blood supply

The extensor pollicis brevis muscle receives arterial blood supply from the posterior and anterior interosseous arteries. Both are branches of the common interosseous artery.