Glenohumeral joint
From Wikipedia, the free encyclopedia
| Glenohumeral joint | |
|---|---|
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| The right shoulder and Glenohumeral joint | |
| Latin | articulatio humeri |
| Gray's | subject #82 315 |
| Dorlands/Elsevier | a_64/12161240 |
The glenohumeral joint, commonly known as the shoulder joint, is a synovial ball and socket joint and involves articulation between the glenoid fossa of the scapula (shoulder blade) and the head of the humerus (upper arm bone). The glenoid fossa is shallow and contains the glenoid labrum which deepens it and aids in stability. With 120 degrees of unassisted flexion, the glenohumeral joint is the most mobile joint in the body. Scapulohumeral rhythm helps to achieve further range of movement. The rotator cuff muscles of the shoulder produce a high tensile force, and help to pull the head of the humerus into the glenoid fossa.
The glenohumeral joint has a loose capsule that is lax inferiorly and therefore is at risk of dislocation inferiorly. The long head of the biceps brachii muscle travels inside the capsule to attach to the supraglenoid tubercle of the scapula. Because the tendon is inside the capsule, it requires a synovial tendon sheath to minimize friction. A number of bursas in the capsule aid mobility.
The capsule can become inflamed and stiff, with abnormal bands of tissue (adhesions) growing between the joint surfaces, causing pain and restricting movement of the shoulder, a condition known as frozen shoulder or adhesive capsulitis.
