Radial styloid process

The radial styloid process is a projection of bone on the lateral surface of the distal radius bone. It extends obliquely downward into a strong, conical projection. The tendon of the brachioradialis attaches at its base, and the radial collateral ligament of the wrist attaches at its apex. The lateral surface is marked by a flat groove for the tendons of the abductor pollicis longus and extensor pollicis brevis.

Breakage of the radius at the radial styloid is known as a Chauffeur's fracture; it is typically caused by compression of the scaphoid bone of the hand against the styloid.