extensor digitorum muscle

The test is performed by tapping the extensor digitorum muscle while the fingers are light or half flexed.

The extensor digitorum muscle (also known as extensor digitorum communis) is a muscle of the posterior forearm present in humans and other animals.

Extension in the humeroulnar joint is produced by the triceps brachii and anconeus muscle, with a tiny contribution from the muscles arising from the lateral epicondyle of the humerus, such as the extensor digitorum muscle.