5.2. Muscular and Skeletal Anatomy

The arm itself consists of three bones. The upper arm is the humerus bone (Figure 5.6). The lower arm consists of two bones: the radius and the ulna. The ulna bone rotates in a hinge fashion around the distal end of the humerus and creates the bony protrusion of the elbow (Figure 5.7). This protrusion is an important skeletal landmark and is called the olecranon process (Figure 5.8), commonly called the elbow.

Figure 5.6. The skeleton of the arm