Shoulder joint Shoulder joint The shoulder joint (or glenohumeral joint from Greek "glene", eyeball, + -"oid", 'form of', + Latin "humerus", shoulder) is structurally classified as a synovial ball and socket joint and functionally as a diarthrosis and multiaxial joint. It involves articulation between the glenoid cavity of the scapula (shoulder blade) and the head of the humerus (upper arm bone). Due to the very loose joint capsule that gives a limited interface of the humerus and scapula, it is the most mobile joint of the human body. The shoulder joint is a ball and socket joint between the scapula and the
Ossification of humerus of the trochlea appears about the age of twelve. Ossification begins in the medial epicondyle about the fifth year, and in the lateral about the thirteenth or fourteenth year. About the sixteenth or seventeenth year, the lateral epicondyle and both portions of the articulating surface, having already joined, unite with the body, and at the eighteenth year the medial epicondyle becomes joined to it. Ossification of humerus The humerus is ossified from "eight" centers, one for each of the following parts: the body, the head, the greater tubercle, the lesser tubercle, the capitulum, the trochlea, and one for each epicondyle.