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Radial Styloid

processus styloideus radii

The radial styloid is a tapered projection from the lateral surface of the distal radius, extending approximately 1 cm distal to the ulnar-facing lunate facet. The brachioradialis tendon inserts at its base, and the first extensor compartment (APL and EPB) passes over a groove at its lateral aspect. The radial collateral ligament of the wrist originates from the styloid tip. It is palpable at the anatomical snuffbox base.

Region: Hand & Wrist

Clinical Relevance

Clinical Notes

The radial styloid is involved in three important fracture patterns: it may fracture as an isolated process (chauffeur fracture or Hutchinson fracture from direct radial impact), as part of a comminuted distal radius fracture, or as an avulsion by the brachioradialis. A radial styloid fracture extending into the scaphoid fossa signals potential radiocarpal instability. De Quervain tenosynovitis affects the first compartment tendons as they pass over the styloid process.

Pathology

Common Injuries & Conditions

Chauffeur Fracture

Intra-articular radial styloid fracture from direct impaction of the scaphoid against the styloid in a fall on an outstretched hand, producing lateral wrist pain and requiring fixation when displaced, as the fracture line extends into the scaphoid fossa of the radiocarpal joint.

De Quervain Tenosynovitis

Tenosynovitis of the first extensor compartment as APL and EPB tendons cross the radial styloid produces lateral wrist and styloid pain with a positive Finkelstein test, managed with immobilisation, injection, and surgical release of the first compartment roof when conservative measures fail.