Humeroulnar joint

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Humeroulnar joint

Left elbow-joint, showing anterior and ulnar collateral ligaments.
Latin	articulatio humeroulnaris
Gray's	subject #84 321
Dorlands/Elsevier	a_64/12161261

The humeroulnar joint, is part of the elbow-joint, between the ulna and humerus bones and is a simple hinge-joint, which allows of movements of flexion and extension only.^[1]

Owing to the obliquity of the trochlea of the humerus, this movement does not take place in the antero-posterior plane of the body of the humerus.

When the forearm is extended and supinated, the axes of the arm and forearm are not in the same line; the arm forms an obtuse angle with the forearm (the carrying angle). During flexion, however, the forearm and the hand tend to approach the middle line of the body, and thus enable the hand to be easily carried to the face.

The accurate adaptation of the trochlea of the humerus, with its prominences and depressions, to the semilunar notch of the ulna, prevents any lateral movement.

Flexion is produced by the action of the Biceps brachii and Brachialis, assisted by the Brachioradialis, with a tiny contribution from the muscles arising from the medial epicondyle of the humerus.

Extension is produced by the Triceps brachii and Anconæus, with a tiny contribution from the muscles arising from the lateral epicondyle of the humerus, such as the Extensor digitorum communis.

^ Janice K. Loudon, Stephania L. Bell, Jane M. Johnston (1998). The Clinical Orthopedic Assessment Guide . Human Kinetics. ISBN 0880115076.

SUNY Labs 10:st-1106 - "Joints of the Upper Extremity: Elbow joint"

This article was originally based on an entry from a public domain edition of Gray's Anatomy. As such, some of the information contained herein may be outdated. Please edit the article if this is the case, and feel free to remove this notice when it is no longer relevant.