Extensor digitorum

The extensor digitorum (Latin: musculus extensor digitorum) is a superficial, long and slim muscle of the forearm that extends between the humerus and fingers. It belongs to the posterior compartment of the forearm muscles and lies in the first or superficial layer. As the name suggests, this muscle is known as one of the extensors.

Origin

The extensor digitorum muscle originates from the lateral epicondyle of the humerus.

Insertion

In hand, the extensor digitorum splits into four tendons that insert in the extensor expansions of the second to fifth fingers.

Action

The extensor digitorum muscle provides finger extension at the second to fifth metacarpophalangeal and interphalangeal joints.

Innervation

The extensor digitorum is innervated by the posterior interosseous branch of the radial nerve (C7, C8). The radial nerve arises from the brachial plexus.

Blood supply

The extensor digitorum muscle receives arterial blood supply from the posterior and anterior interosseous arteries and radial recurrent artery. The first two arteries are branches of the common interosseous artery, while the radial recurrent artery arises from the radial artery.