Radius
The radius is the lateral bone of the forearm, extending from the elbow to the wrist. It is the main bone involved in forearm rotation (pronation and supination) and articulates with the carpal bones at the wrist.
Key Features
Articulations
- •Elbow joint (head with capitulum) - pivot
- •Proximal radioulnar joint (head with radial notch of ulna) - pivot
- •Distal radioulnar joint (ulnar notch with ulna head) - pivot
- •Wrist joint (with scaphoid and lunate)
Muscle Attachments
Clinical Relevance
Colles fracture (distal radius with dorsal displacement) is the most common wrist fracture. The radius is essential for wrist stability and forearm rotation. Radial nerve injury can occur with fractures.
Radius FAQs
Common questions about this bone
A Colles fracture is a fracture of the distal radius with dorsal displacement and angulation, typically from falling on an outstretched hand (FOOSH injury). It causes a 'dinner fork' deformity when viewed from the side.
The radius pivots around the ulna during pronation and supination. At the proximal radioulnar joint, the radial head rotates. At the distal joint, the radius moves around the relatively fixed ulna head.
The radius forms most of the wrist joint, articulating with the scaphoid and lunate carpal bones. The ulna does not directly contact the carpal bones; an articular disc fills this space.
Lister's tubercle is a bony prominence on the dorsal distal radius that acts as a pulley for the extensor pollicis longus tendon. It is a landmark for wrist joint injection and can be fractured.