A Colles fracture involves the:

A Colles fracture involves the:

• A. Radius
• B. Ulna
• C. Tibia
• D. Fibula

Answer: (A)

A distal radius fracture with backward (dorsal) displacement after a fall on an outstretched hand is the classic Colles pattern. This injury specifically involves the radius near the wrist, and the distal fragment tilts posteriorly, often producing the recognizable dinner-fork deformity. The ulna is not the primary bone involved in this pattern, though an accompanying fracture of the ulnar styloid can occur in some cases. The tibia and fibula are leg bones and are not related to this wrist injury.

A distal radius fracture with backward (dorsal) displacement after a fall on an outstretched hand is the classic Colles pattern. This injury specifically involves the radius near the wrist, and the distal fragment tilts posteriorly, often producing the recognizable dinner-fork deformity. The ulna is not the primary bone involved in this pattern, though an accompanying fracture of the ulnar styloid can occur in some cases. The tibia and fibula are leg bones and are not related to this wrist injury.