Flexion is carried out by the anterior fibres of the deltoid, pectoralis major and the coracobrachialis.Flexion and extension of the shoulder joint in the ( sagittal plane).Such an imbalance could cause a forward head carriage which in turn can affect the range of movements of the shoulder.

This could be an imbalance in parts of the large trapezius muscles that hold the scapula in place. This range can be compromised by anything that changes the position of the scapula. The movement of the scapula across the rib cage in relation to the humerus is known as the scapulohumeral rhythm, and this helps to achieve a further range of movement. The muscles shown are subscapularis muscle (at right), infraspinatus muscle (at top left), teres minor muscle (at bottom left) The shoulder joint is supplied with blood by branches of the anterior and posterior circumflex humeral arteries, the suprascapular artery and the scapular circumflex artery.Īnimation of the shoulder joint.

They are the suprascapular nerve, the axillary nerve and the lateral pectoral nerve. The nerves supplying the shoulder joint all arise in the brachial plexus. These ligaments are weak unlike its posterior part which is supported by the infraspinatus muscle. It is the thickenings of the capsule that pass from the upper part of glenoid to lesser tuberosity and inferior part of the head of humerus. Superior, middle and inferior glenohumeral ligaments.The supraspinatus, infraspinatus and teres minor muscles aid in abduction and external rotation. The tendons of the rotator cuff and their respective muscles ( supraspinatus muscle, infraspinatus, teres minor, and subscapularis) stabilize and fix the joint.

Other long muscles such as pectoralis major, latissimus dorsi, teres major and deltoid muscles also provide support to the shoulder joint. The tendon of the long head of the biceps brachii passes through the bicipital groove on the humerus and inserts on the superior margin of the glenoid cavity to press the head of the humerus against the glenoid cavity. The primary stabilizers of the shoulder include the biceps brachii on the anterior side of the arm, and tendons of the rotator cuff which are fused to all sides of the capsule except the inferior margin. The shoulder joint is a muscle-dependent joint as it lacks strong ligaments. The supra-acromial bursa does not normally communicate with the shoulder joint.

Between the capsule and the tendon of the subscapularis muscle is the subscapular bursa, this is also known as the subtendinous bursa of the scapularis.

The coracobrachial bursa is between the subscapularis muscle and the tendon of the coracobrachialis muscle.

The subcoracoid bursa is between the capsule and the coracoid process of the scapula.

Between the capsule and the acromion is the subacromial bursa.

Between the joint capsule and the deltoid muscle is the subacromial-subdeltoid bursa.

Bursae of shoulder joint: (1) and (6) subacromial-subdeltoid bursa, (2) subscapular recess, (3) subcoracoid bursa, (4) coracoclavicular bursa, (5) supra-acromial bursaĪ number of small fluid-filled sacs known as synovial bursae are located around the capsule to aid mobility:

Abduction of shoulder