The Elbow Joint

The elbow is a hinge joint composed of two articulations—the humeroulnar joint, where the trochlea of the

Saladin: Anatomy & I 9. Joints I Text I I © The McGraw-Hill

Physiology: The Unity of Companies, 2003 Form and Function, Third Edition

312 Part Two Support and Movement

Acromion -Subacromial bursa

Supraspinatus tendon

Coracohumeral ligament

Subdeltoid-

bursa

Subscapularis tendon Transverse humeral ligament Tendon sheath

Biceps brachii tendon (long head)

Humerus

Supraspinatus tendon Acromion Capsular ligament Subdeltoid bursa Deltoid muscle

Subscapular Bursa

Humerus

Clavicle

Coraco-

clavicular ligament

Coraco-acromial ligament

Coracoid process

Subcoracoid bursa

Subscapular bursa

Glenohumeral ligaments

Humerus

Subscapular Bursa

Synovial membrane

Glenoid cavity of scapula

Glenoid labrum

Synovial membrane

Glenoid cavity of scapula

Glenoid labrum

Figure 9.19 The Humeroscapular (shoulder) Joint.

(a) Anterior view; (b) lateral view of the glenoid cavity and labrum with the humerus removed; (c) frontal section of the right shoulder joint, anterior view; (d) photograph of the joint.

Acromion

Supraspinatus tendon

Subdeltoid bursa

Infraspinatus tendon

Glenoid cavity (articular cartilage)

Teres minor tendon

Synovial membrane (cut)

Subscapular Bursa

Coracoid process

Coracohumeral ligament

Superior glenohumeral ligament

Biceps brachii tendon (long head)

Subscapular bursa

Subscapularis tendon

Middle glenohumeral ligament

Inferior glenohumeral ligament

Glenohumeral Ligament
(d)

humerus joins the trochlear notch of the ulna, and the humeroradial joint, where the capitulum of the humerus meets the head of the radius (fig. 9.20). Both are enclosed in a single joint capsule. On the posterior side of the elbow, there is a prominent olecranon bursa to ease the movement of tendons over the elbow. Side-to-side motions of the elbow joint are restricted by a pair of ligaments, the radial (lateral) collateral ligament and ulnar (medial) collateral ligament.

Another joint occurs in the elbow region, the proximal radioulnar joint, but it is not involved in the hinge. At this joint, the disclike head of the radius fits into the radial notch of the ulna and is held in place by the annular liga ment, which encircles the head of the radius and attaches at each end to the ulna. The radial head rotates like a wheel against the ulna as the forearm is rotated.

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