The musculus extensor pollicis longus, also known as the extensor pollicis longus muscle, is a skeletal muscle located in the forearm. It is an extensor muscle specifically responsible for the movement and control of the thumb.
Originating from the posterior surface of the ulna bone and adjacent interosseous membrane, the musculus extensor pollicis longus forms a long tendon that runs through a groove on the back of the radius bone. It then proceeds to insert onto the base of the distal phalanx of the thumb, enabling its extension.
The role of the musculus extensor pollicis longus is to facilitate various actions involving the thumb, such as extending and lifting it away from the palm, enhancing grip strength, and allowing for precision movements. Its contraction is essential for performing tasks that require dexterity and the ability to grasp objects firmly.
In addition, the musculus extensor pollicis longus works synergistically with other muscles of the forearm, such as the musculus extensor carpi radialis longus and the musculus extensor carpi radialis brevis, to assist in the extension and radial deviation of the wrist joint.
Due to its unique anatomical location and functional significance, the musculus extensor pollicis longus plays a crucial role in enabling precise hand movements, promoting manual coordination, and supporting activities that require a strong and controlled thumb extension.
