Trauma X-ray - Upper limb

Radius and ulna

Typical fracture patterns arise in the forearm bones depending on mechanism of injury and the age of the patient.

In the elderly, osteoporotic fractures of the distal radius are common. In children, bone compliance allows for buckle or 'greenstick' type injuries.

Many fractures of the forearm have eponymous titles. Use of these terms often leads to confusion, and so should be used with caution.

Key points

  • Forearm fractures are characteristic depending on age
  • Use the many eponyms with caution
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Distal radius fracture - Dorsal displacement

  • Transverse fracture of the distal radius
  • Dorsal angulation and displacement of the wrist results in a so called 'dinner fork' deformity
  • Shortening results in a very narrowed ulnocarpal space (*)
  • This injury (or similar) - most common in elderly osteoporotic women - is often referred to as a 'Colle's fracture'
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Distal radius fracture - Palmar displacement

  • Palmar (volar) displacement and angulation
  • Shortened radius
  • This injury is often referred to as a 'reverse Colle's' fracture or 'Smith's' fracture
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Distal radius fracture - Comminuted

  • High degree of comminution of the distal radius and a displaced fracture of the ulnar styloid
  • A fracture involving the articular surface with dorsal displacement of the wrist bones can be referred to as a Barton's fracture
  • Some may call this a type of Colle's fracture
  • NOTE - This image demonstrates why eponyms are best avoided unless the meaning is clear - a full description is usually best

Forearm fracture/dislocation

The radius and ulna form an anatomical unit, joined throughout their length by an interosseous ligament and stabilised at the elbow and wrist, thus forming a ring. If there is a fracture of the shaft of one of these bones with visible shortening, there will likely be dislocation at the wrist or elbow of the other.

If the ulnar shaft fractures with shortening, then the radius will dislocate at its point of weakness at the elbow (Monteggia fracture-dislocation). If the radius fractures with shortening, then the ulna will dislocate at its point of weakness at the distal radioulnar joint (Galeazzi fracture-dislocation).

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Forearm fracture/dislocation - Monteggia type

  • Displaced fracture of the ulna with shortening
  • Loss of alignment of the radiocapitellar line due to dislocation of the radial head
  • NOTE - The radiocapitellar line should pass through the middle of the capitulum (C)

Forearm fractures of childhood

Children's bones are more compliant and therefore often buckle rather than completely break as in adults. If there is a visible fracture in the cortex on one side with buckling on the other this is termed a 'greenstick' fracture. Buckling without a visible fracture line is termed a 'torus' injury.

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Greenstick fracture

  • The palmar (volar) cortical surface of the radius is buckled
  • There is a visible fracture through the dorsal cortex of the radius
  • Normal ulna
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Torus fracture

  • Buckled radius
  • No visible fracture line

©Radiology Masterclass 2007 -