Extrinsic extensor muscles of the hand

Extrinsic extensor muscles of the hand are a group of muscles located in the posterior compartment of the forearm. These muscles are primarily responsible for the extension of the wrist and fingers. The extrinsic extensor muscles of the hand include the Extensor carpi radialis longus, Extensor carpi radialis brevis, Extensor digitorum, Extensor digiti minimi, Extensor carpi ulnaris, Abductor pollicis longus, Extensor pollicis brevis, and Extensor pollicis longus.

Anatomy

The extrinsic extensor muscles of the hand originate from the lateral epicondyle of the humerus and insert into various locations on the hand and fingers. They are innervated by the Radial nerve and receive blood supply from the Radial artery and Ulnar artery.

Extensor carpi radialis longus

The Extensor carpi radialis longus originates from the lateral supracondylar ridge of the humerus and inserts into the base of the second metacarpal. It is responsible for extending and abducting the wrist.

Extensor carpi radialis brevis

The Extensor carpi radialis brevis originates from the lateral epicondyle of the humerus and inserts into the base of the third metacarpal. It is responsible for extending and abducting the wrist.

Extensor digitorum

The Extensor digitorum originates from the lateral epicondyle of the humerus and inserts into the extensor expansion of the medial four digits. It is responsible for extending the fingers and wrist.

Extensor digiti minimi

The Extensor digiti minimi originates from the lateral epicondyle of the humerus and inserts into the extensor expansion of the fifth digit. It is responsible for extending the little finger and wrist.

Extensor carpi ulnaris

The Extensor carpi ulnaris originates from the lateral epicondyle of the humerus and inserts into the base of the fifth metacarpal. It is responsible for extending and adducting the wrist.

Abductor pollicis longus

The Abductor pollicis longus originates from the posterior surface of the radius and ulna and inserts into the base of the first metacarpal. It is responsible for abducting and extending the thumb.

Extensor pollicis brevis

The Extensor pollicis brevis originates from the posterior surface of the radius and inserts into the base of the proximal phalanx of the thumb. It is responsible for extending the thumb.

Extensor pollicis longus

The Extensor pollicis longus originates from the posterior surface of the ulna and interosseous membrane and inserts into the base of the distal phalanx of the thumb. It is responsible for extending the thumb.

Clinical significance

Injury or damage to the extrinsic extensor muscles of the hand can result in a loss of hand function. Conditions such as Tennis elbow and Radial tunnel syndrome can affect these muscles.

See also

• Intrinsic muscles of the hand
• Flexor muscles of the hand

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  Extrinsic extensor muscles of the hand - Image 1

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  Extrinsic extensor muscles of the hand - Image 2