The tendons of the rotator cuff, not the muscles, are most commonly involved, and of the four, the supraspinatus is most frequently affected, as it passes below the acromion.
32.
It does not properly belong to the acromioclavicular joint articulation, but is usually described with it, since it forms a most efficient means of retaining the clavicle in contact with the acromion.
33.
It does not properly belong to the acromioclavicular ( AC ) joint articulation, but is usually described with it, since it forms a most efficient means of retaining the clavicle in contact with the acromion.
34.
The scapula is ossified from 7 or more centers : one for the body, two for the coracoid process, two for the acromion, one for the vertebral border, and one for the inferior angle.
35.
The final common factor is impingement syndrome, the most common nonsports-related injury and which occurs when the tendons of the rotator cuff muscles become irritated and inflamed while passing through the subacromial space beneath the acromion.
36.
The ligament is sometimes described as consisting of two marginal bands and a thinner intervening portion, the two bands being attached respectively to the apex and the base of the coracoid process, and joining together at the acromion.
37.
A scapula ( shoulder blade ), only tentatively assigned to " Plesiorycteropus ", has the acromion, a radius, a compact and massive bone in " Plesiorycteropus " which resembles the pangolin radius.
38.
The deltoid muscle covers the shoulder joint on three sides, arising from the front upper third of the clavicle, the acromion, and the spine of the scapula, and travelling to insert on the deltoid tubercle of the humerus.
39.
To stop this compressing against the undersurface of the acromion the humeral head and injuring the supraspinatus tendon, there is a simultaneous contraction of some of the muscles of the rotator cuff : the infraspinatus and subscapularis primarily perform this role.
40.
It is attached, by its apex, to the summit of the acromion just in front of the articular surface for the clavicle; and by its broad base to the whole length of the lateral border of the coracoid process.
