The proximal end of the radius illustrates the relationship of form and function. The cup-like surface of the radial head articulates with the rounded shape of the capitulum. This forms a joint that allows for________ .
A) the hinge like motion of the forearm
B) the curling of the fingers
C) the rotational motion of the forearm
D) the hyper extension of the forearm

Question

Quizplus · Accepted Answer

The rotational motion of the forearm is allowed by the articulation between the rounded shape of the capitulum and the cup-like surface of the radial head. This joint allows the radius to rotate around the ulna during pronation and supination of the forearm. Choice A is incorrect because hinge-like motion refers to movement in one plane only, whereas the radius allows for rotational motion. Choice B is incorrect because the curling of the fingers is not directly related to the function of the proximal end of the radius. Choice D is incorrect because hyperextension of the forearm refers to movement beyond the normal range of motion and is not a typical motion of the forearm.

The Proximal End of the Radius Illustrates the Relationship of Form