Question

Articulating surfaces on the superior aspect of radius and ulna

Answer 1

This is a projection of the lateral aspect of the distal end of the radial bone that margins the carpal articular surface superiorly. 

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Answer 2

The radioulnar joints are two locations in which the radius and ulna articulate in the forearm:

Proximal radioulnar joint: This is located near the elbow, and is an articulation between the head of the radius, and the radial notch of the ulna.Distal radioulnar joint: This is located near the wrist, and is an articulation between the ulnar notch of the radius, and the ulnar head.