One of two long bones of the forearm, located on the thumb side and rotating around the ulna.
Structure
The radius has a disc-shaped head proximally that articulates with the capitulum of the humerus and the ulna. Its shaft widens distally into a broad surface that forms most of the wrist joint with the carpal bones.
Rotation
During pronation the radius pivots around the ulna, crossing over it. This motion turns the palm downward. Supination returns the radius to a parallel position with the palm up.
Landmarks
The radial tuberosity on the upper shaft anchors the biceps brachii tendon. The styloid process at the distal end can be felt at the wrist on the thumb side.
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Radius starts with R and ends with S. Browse other body parts along the same letter.
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