Final answer:
The head of the radius articulates with the capitulum of the humerus at the radiocapitellar joint, with the contact surface being relatively small but allowing for various elbow and forearm movements.
Step-by-step explanation:
The head of the radius is indeed a disc-shaped structure that forms the proximal end of the radius, interacting primarily with the radiocapitellar joint at the elbow. This joint is where the head of the radius articulates with the capitulum of the humerus. The small depression on the head of the radius allows for a specific point of contact with the capitulum. However, the amount of contact is not considered 'large' because the articulating surface on the radial head is relatively small but precise, enabling a variety of movements at the elbow, which include flexion and extension, as well as some rotation of the forearm.
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