4. How is the shape of the glenoid cavity of the scapula different from that of the acetabulum in the hip bone? How do the shapes of these bone markings affect the range of motion at their respective joints?

1. The glenoid cavity is the shoulder structure that serves as the “socket.” The humeral head fits into the shallow glenoid cavity, providing the “ball” to make up the ball and socket joint. Compared to the hip “socket,” or acetabulum, the lack of depth in the cavity affords the humerus complete rotation about the joint. 2. Many of the bones include external markings or features - projections, depressions, and openings. Depending on their structure, these markings may serve as attachment sites for muscles, ligaments, and tendons or as passageways for blood vessels and nervous tissue.

Explanation: