Extensor digiti minimi

The extensor digiti minimi (Latin: musculus extensor digiti minimi) is a slender, long superficial muscle of the forearm that extends between the humerus and fifth finger. It belongs to the posterior compartment of the forearm muscles and lies in the first or superficial layer. As the name suggests, this muscle extends the fifth finger.

Origin

The extensor digiti minimi muscle originates from the lateral epicondyle of the humerus.

Insertion

The extensor digiti minimi inserts on the bases of the middle and distal phalanges of the fifth finger.

Action

The extensor digiti minimi muscle provides the extension of the fifth finger at the fifth metacarpophalangeal and interphalangeal joints.

Innervation

The extensor digiti minimi 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 digiti minimi 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.