Final answer:
The annular ligament helps stabilize the radial head and allows for rotation of the radius during forearm movement.
Step-by-step explanation:
The annular ligament helps to stabilize the radial head.
This ligament encircles the head of the radius and supports it as it articulates with the radial notch of the ulna at the proximal radioulnar joint. The proximal radioulnar joint is a pivot joint that allows for rotation of the radius during supination and pronation of the forearm.