Extensor carpi radialis brevis

The extensor carpi radialis brevis (Latin: musculus extensor carpi radialis brevis) is a slim and long superficial muscle of the forearm that stretches between the humerus and the third metacarpal bone. It belongs to the lateral compartment of the forearm muscles. The extensor carpi radialis brevis is the deepest muscle of the lateral forearm compartment, and it lies inferior to the extensor carpi radialis longus muscle.

Origin

The extensor carpi radialis brevis muscle originates from the lateral epicondyle of the humerus.

Insertion

The extensor carpi radialis brevis descends and inserts on the base of the third metacarpal bone.

Action

The extensor carpi radialis brevis muscle together with the extensor carpi radialis longus provides the extension and abduction of the hand at the wrist joint.

Innervation

The extensor carpi radialis brevis is innervated by the radial nerve (C7, C8) - a branch of the brachial plexus.

Blood supply

The extensor carpi radialis brevis muscle receives arterial blood supply from the radial recurrent, radial and radial collateral arteries. The radial recurrent artery arises from the radial artery, while the radial collateral artery is a branch of the deep brachial artery.