Causes

How do fractures of the forearm commonly happen?

All fractures occur when the limb is subjected to stress outside the normal range. Forearm fractures most commonly occur in three situations - a blow on the forearm, a bending force as in falling on the outstretched hand, or a twisting force where the forearm is over-rotated. Most often these forces cause both bones to break, but a fracture of the ulna alone can occur if you put your arm up to ward off a blow. This isolated fracture of the ulna used to be called the nightstick fracture! Nowadays, the pattern is more common in sports collisions, motor vehicle accidents (MVAs), and falls but it does still occur with violent assault.

Twisting and bending fractures occur with falls, sports accidents, and MVAs. As with all fractures, the damage done to the muscles and tendons is a significant feature of the injury. Open fractures, where the bone comes out through the skin are quite common in the forearm.