Extensor Pollicis Longus

The Extensor Pollicis Longus can be seen on the radial side of the wrist, at the base of the thumb where it forms the lower border of the 'anatomical snuffbox' a triangular shape between two tendons. The Extensor pollicis longus is much larger than the Extensor pollicis brevis muscle, the origin of which it partly covers.

Anatomy of the Extensor Pollicis Longus

The extensor pollicis longus is innervated by the Posterior interosseous nerve and arises from the lateral part of the middle third of the dorsal surface of the body of the ulna below the origin of the Abductor pollicis longus, and from the interosseous membrane.

It ends in a tendon, which passes through a separate compartment in the dorsal carpal ligament, lying in a narrow, oblique groove on the back of the lower end of the radius.

It then crosses obliquely the tendons of the Extensors 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; and is finally inserted into the base of the last phalanx of the thumb.

Functions of the Extensor Pollicis Longus

The Extensor pollicis longus extends the terminal phalanx of the thumb. It is also used in the extension of the wrist.

You will normally use the muscle when releasing your grip on an object.

The muscle can be strengthened by exercises that include the wrist extensor stretch and wrist extension with a resistance band.

Bookmark this:

Bookmark this page