Fig. 5.

Glenohumeral joint. (a) The long-axis convexity of the humeral head aligns along the short convexity of the glenoid (black line), and the short convexity of the humeral head aligns along the long-axis concavity of the glenoid (white line) forming a hemisellar arrangement. The open cranial and caudal margins of the joint allow an additional degree of freedom, translational sliding. (b) Typical path of the humerus during a single stride in lateral view after vertebral and coracosternal motions are factored out. 1 = beginning of stance phase; 6 = end of swing phase. (c) Translational sliding slightly increases the displacement of the elbow during a single representative stride.