Extensor pollicis et indicis communis muscle

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Extensor pollicis et indicis communis muscle

The extensor pollicis et indicis communis muscle is a muscle in the forearm that is involved in the extension of the thumb and index finger. This muscle is part of the extensor compartment of the forearm and plays a crucial role in hand movements.

Anatomy

The extensor pollicis et indicis communis muscle originates from the posterior surface of the ulna and the interosseous membrane. It is situated deep to the extensor digitorum muscle and the extensor carpi ulnaris muscle.

Insertion

The muscle inserts into the extensor expansions of the thumb and index finger. The tendon for the thumb is often referred to as the extensor pollicis longus tendon, while the tendon for the index finger is known as the extensor indicis tendon.

Nerve Supply

The muscle is innervated by the posterior interosseous nerve, which is a branch of the radial nerve.

Blood Supply

The blood supply to the extensor pollicis et indicis communis muscle is provided by the posterior interosseous artery, a branch of the common interosseous artery.

Function

The primary function of the extensor pollicis et indicis communis muscle is to extend the thumb and index finger. This action is essential for various hand movements, including gripping and releasing objects.

Clinical Significance

Injuries or conditions affecting the extensor pollicis et indicis communis muscle can lead to difficulties in thumb and index finger extension. Conditions such as tenosynovitis or radial nerve palsy can impair the function of this muscle.

Related Muscles

• Extensor digitorum muscle
• Extensor carpi ulnaris muscle
• Extensor pollicis longus muscle
• Extensor indicis muscle

See Also

• Forearm muscles
• Hand anatomy
• Radial nerve