Scaphoid

The scaphoid is one of the eight carpal bones of the wrist. It is located on the thumb side in the proximal row and has a boat-like shape, which gives it the origin of its name from the Greek skaphē, meaning boat. The scaphoid plays a key role in linking the proximal and distal carpal rows and in transmitting load from the hand to the forearm during wrist movements.

Anatomy and articulations

The bone has a proximal pole that participates in the radiocarpal joint with the radius, a body or waist, and a distal pole that articulates with the capitate and, to a lesser extent, with the trapezium. Medially it forms a joint with the lunate. Its unique shape and position contribute to wrist mobility and stability, and its narrow waist makes it susceptible to fracture.

Blood supply and clinical significance

The scaphoid receives its arterial blood primarily from branches of the radial artery, which enter distally and travel proximally through the bone. This retrograde blood supply means the proximal pole is at higher risk of avascular necrosis if a fracture disrupts the supply. The scaphoid is the most commonly fractured carpal bone, often resulting from a fall on an outstretched hand.

Fractures and management

Scaphoid fractures typically present with pain and tenderness in the anatomic snuffbox after a fall. Diagnosis is via radiographs, though some fractures may be occult and require MRI or CT. Non-displaced fractures may be treated with immobilization in a cast for several weeks, while displaced or unstable fractures often require surgical fixation. Healing can be slow, especially for proximal pole fractures, and nonunion or avascular necrosis may occur if treatment is delayed.