Health Dictionary
Reliable, easy-to-read patient information on common medical conditions — written in plain language, free of jargon, and grounded in current evidence. Browse the most frequent diagnoses, understand what they mean for everyday life, and learn which steps and questions help you have a focused conversation with your doctor.
Extensor carpi ulnaris muscle
Introduction
Extensor carpi ulnaris is a muscle located in the human forearm that acts to extend and adduct the wrist.
Being an extensor muscle, extensor carpi ulnaris is on the posterior side of the forearm.
Origin and insertion
Origin and insertion
It originates from the lateral epicondyle of the humerus and the posterior border of the ulna, and crosses the forearm to the ulnar (medial) side to insert at the base of the 5th metacarpal.
Action
Action
The Extensor carpi ulnaris extends the wrist, but when acting alone inclines the hand toward the ulnar side; by its continued action it extends the elbow-joint.
The muscle is a minor extensor of the carpus in carnivores, but has become a flexor in ungulates. In this case it is described as ulnaris lateralis.
Additional images
Additional images
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Bones of left forearm. Posterior aspect. -
Bones of the left hand. Dorsal surface. -
Cross-section through the middle of the forearm. -
Posterior surface of the forearm. Deep muscles. -
Transverse section across distal ends of radius and ulna. -
Transverse section across the wrist and digits. -
The mucous sheaths of the tendons on the back of the wrist.
