Which action occurs when the extensor digitorum muscle contracts?

When the extensor digitorum muscle contracts, it primarily facilitates wrist extension. The extensor digitorum is a muscle located in the posterior compartment of the forearm and is specifically responsible for the extension of the fingers. However, its contraction also contributes to wrist extension due to its anatomical connections and the line of pull it has during movement.

When the muscle contracts, it pulls on the tendons that connect to the posterior side of the hand and fingers. This leads to the extension of the proximal interphalangeal joints and the metacarpophalangeal joints of the fingers. The action of extending these joints also creates leverage that extends the wrist, allowing for the simultaneous movement of both the wrist and the fingers during activities such as typing, playing an instrument, or throwing.

In contrast, the other actions referenced in the choices do not occur during the contraction of the extensor digitorum. For instance, digit 1 extension specifically relates to the thumb, which is primarily controlled by other muscles such as the extensor pollicis longus and brevis. Wrist flexion involves different muscle groups located in the anterior compartment of the forearm. Lastly, elbow flexion also requires the action of muscles like the biceps bra