Extensor pollicis longus muscle

Extensor pollicis longus muscle
Posterior surface of the forearm. Deep muscles. Extensor pollicis longus muscle is labeled in purple.
Details
Origin	Middle third of posterior surface of ulna, interosseous membrane
Insertion	thumb, distal phalanx
Artery	posterior interosseous artery
Nerve	posterior interosseous nerve (branching from the radial nerve)
Actions	extension of the thumb (metacarpophalangeal and interphalangeal)
Antagonist	Flexor pollicis longus muscle, Flexor pollicis brevis muscle
Identifiers
Latin	musculus extensor pollicis longus
Dorlands /Elsevier	m_22/12548955
TA	A04.6.02.051
FMA	38521
Anatomical terms of muscle []

In human anatomy, the extensor pollicis longus muscle (EPL) is a skeletal muscle located dorsally on the forearm. It is much larger than the extensor pollicis brevis, the origin of which it partly covers and acts to stretch the thumb together with this muscle.

The extensor pollicis longus arises from the dorsal surface of the ulna and from the interosseous membrane, next to the origins of abductor pollicis longus and extensor pollicis brevis.

Passing through the third tendon compartment, lying in a narrow, oblique groove on the back of the lower end of the radius, it crosses the wrist close to the dorsal midline before turning towards the thumb using Lister's tubercle on the distal end of the radius as a pulley.

It obliquely crosses the tendons of the extensores carpi radialis longus and brevis, and is separated from the extensor pollicis brevis by a triangular interval, the anatomical snuff box in which the radial artery is found.

At the proximal phalanx, the tendon is joined by expansions from abductor pollicis brevis and adductor pollicis.

The tendon is finally inserted on the base of the distal phalanx of the thumb.