What happens to the radial head when the forearm is pronated?

What happens to the radial head when the forearm is pronated?

• A. Moves Anteriorly
• B. Moves Posteriorly
• C. Stays in Place
• D. Rotates Medially

Answer: (B)

When you pronate, the radius rotates around the ulna at the proximal radioulnar joint. The radial head is held in place by the annular ligament and articulates with the ulna’s radial notch, so as the radius turns, the head must glide a bit to accommodate the motion. In pronation, this glide is posterior, allowing the radius to rotate around the ulna while the ulna stays fixed. So the radial head moves posteriorly. It isn’t simply staying in place, nor is the primary change described as a medial rotation of the head.

When you pronate, the radius rotates around the ulna at the proximal radioulnar joint. The radial head is held in place by the annular ligament and articulates with the ulna’s radial notch, so as the radius turns, the head must glide a bit to accommodate the motion. In pronation, this glide is posterior, allowing the radius to rotate around the ulna while the ulna stays fixed. So the radial head moves posteriorly. It isn’t simply staying in place, nor is the primary change described as a medial rotation of the head.