Introduction: the shoulder joint is a synovial joint of the ball and socket variety. It is formed between the head of the humerus and the relatively shallow and small glenoid fossa of the scapula
A. Anterior
1. Capsule which opens to communicate with subscapularis bursa
2. Subscapularis
3. Middle humeral ligament
4. Coracobrachialis
5. Short head biceps
6. Pectoralis major
7. Anterior fibre of deltoid
B. Posterior
1. Capsule
2. Intraspinatus tendon
3. Trees minor
4. Posterior fibres of deltoid
C. Superior
1. Capsule
2. Superior glenohumeral ligament
3. Long head of biceps
4. Supraspinatus tendon
5. Subacromial bursa
6. Deltoid bursa
7. Deltoid muscle
8. Acromion
9. Coracoacrominal ligament
D. Inferior
1. Capsule, lax and in the adducted position forms the axillary cortex
2. Inferior glenohumeral ligament
3. Long head of triceps
Stability: the capsule of the joint is thin and loose thus allowing a wide range of movement. The stability is ensured by muscles, ligaments and capsule surrounding it because the bony articulations are not stable
Importance: dislocation of the shoulder joint are most common on the inferior side because laxing of the capsule and the muscle relations are not much.