How many muscles are in the posterior compartment of the forearm?

There are 12 muscles total, divided into two groups: 7 superficial muscles that cross the elbow joint and 5 deep muscles that do not cross the elbow joint.

What nerve innervates the muscles on the back of the forearm?

All posterior forearm muscles are innervated by the radial nerve or its branches. The superficial muscles receive supply from the radial nerve directly, while most deep muscles are innervated by the posterior interosseous nerve (the deep branch of the radial nerve).

Which muscles originate from the common extensor origin?

Four superficial muscles originate from the common extensor origin on the lateral epicondyle of the humerus: Extensor carpi radialis brevis, Extensor digitorum, Extensor digiti minimi, and Extensor carpi ulnaris.

What are the outcropping muscles and what do they do?

The outcropping muscles are three deep muscles that emerge between superficial layers to act on the thumb: Abductor pollicis longus (abducts thumb), Extensor pollicis brevis (extends proximal thumb phalanx), and Extensor pollicis longus (extends all thumb joints).

What is the difference between superficial and deep posterior forearm muscles?

Superficial muscles are more superficial, cross the elbow joint, and get radial nerve innervation directly. Deep muscles lie underneath, don't cross the elbow, get posterior interosseous nerve innervation, and include thumb/index specialists and the supinator.

Which muscles extend the wrist?

Wrist extensors include Extensor carpi radialis longus and brevis (extend and abduct), Extensor carpi ulnaris (extends and adducts), plus Extensor digitorum, digiti minimi, pollicis longus, and indicis which assist in wrist extension.

What is the function of the brachioradialis muscle?

Brachioradialis flexes the elbow (especially in mid-prone position) and assists in returning the forearm to mid-prone position from supination or pronation.

Posterior Forearm Muscles – Wrist & Finger Extensors

❓ Frequently Asked Questions