The proximal end of the radius consists of a head, a neck, and the radial tuberosity (Fig. 7.62A,B).
The head of the radius is a thick disc-shaped structure oriented in the horizontal plane. The circular superior surface is concave for articulation with the capitulum of the humerus. The thick margin of the disc is broad medially where it articulates with the radial notch on the proximal end of the ulna.