In a Colles fracture, the distal fragment is displaced in which direction relative to the proximal fragment?

Explanation

## Colles Fracture: Displacement Pattern **Key Point:** A Colles fracture is a transverse fracture of the distal radius with dorsal and radial displacement of the distal fragment. This is the classic "dinner fork" deformity seen on lateral X-ray. ### Mechanism of Displacement The fracture typically occurs 2–3 cm proximal to the wrist joint when a person falls on an outstretched hand (FOOSH injury) with the wrist extended and supinated. The dorsal displacement occurs due to the mechanism of injury and the pull of the extensor carpi radialis longus and brevis muscles. ### Radiological Features | Feature | Colles Fracture | | --- | --- | | **Displacement direction** | Dorsal and radial | | **Angulation** | Dorsal angulation (loss of volar tilt) | | **Associated injury** | Ulnar styloid fracture (50–60%) | | **Radial shortening** | Common | | **Supination/pronation** | Supinated position at injury | **High-Yield:** The mnemonic "**DORSAL**" helps recall: **D**istal radius, **O**utstretched hand, **R**adial displacement, **S**upinated, **A**ngulation dorsal, **L**ateral view shows dinner fork, **L**oss of volar tilt. **Clinical Pearl:** On lateral radiograph, the normal volar tilt of the distal radius (10–12°) is reversed to dorsal tilt, creating the pathognomonic "dinner fork" silhouette. ### Comparison with Smith Fracture Smith fracture (reverse Colles) shows **volar displacement** of the distal fragment—opposite to Colles—and occurs with flexion injuries (falling on flexed wrist).