Fracture of shafts of radius and ulna is a fracture of radial and ulnar shafts occurring simultaneously. It often occurs in the middle or lower one-third of the radius and ulna in elder children and adults. Fractures caused by direct violent force are often transverse or comminuted with the fracture lines being mostly at the same level. And it may be open fracture due to serious damage of local soft tissues.  Fractures caused by transmitted force occur mostly in the condition that the palm touches the ground first when falling down. The force transmitted to the middle or upper section leads to transverse radial fracture and the residual force results in oblique ulnar fracture through traction of interosseous membrane to the ulna.

The fracture lines are commonly not at the same level, with the radial fracture line being superior to the ulnar fracture line. A greater violence may cause open fracture because of penetration of the fractured end into the skin.  A turned-round violence may cause spiral fracture by resulting in extreme pronation or supination of the forearm. The fracture lines are not at the same level, with the ulnar fracture line superior to the radial fracture line. In the case of complete fractures of the two bones, the fracture ends may overlap, spiral, angulate and displace laterally. There may occur compartment syndrome of antebrachial fascia in the fractures of serious displacement or soft tissue injury.