Answer
The ulna and radius are the bones of the forearm. They articulate with each other in three places:
1. Proximally the radius and the ulna articulate at the proximal radioulnar joint. This joint is formed by the meeting of the head of the radius and the radial notch of the ulna.
2. The distal articulation of radius and ulna is where the head of the ulna meets ulnar notch of the radius
3. The interosseous membrane between the shafts of the radius and ulna is not technically a joint, but it is the third site of the meeting of the radius and ulna.
Work Step by Step
There are three sites where radius and ulna meet. First site is the proximal radioulnar joint . Here the head o the radius articulates with he radial notch of the ulna. Distally the head of the ulna articulates with the ulnar notch of the radius. These joints facilitate the movements of pronation and supination.
A so-called interosseous membrane of connective tissue links the shafts of radius and ulna. This membrane is also a site of attachment for some tendons and muscles of the forearm.
