In a torus fracture, what is the primary cause of this injury?

In a torus fracture, also known as a buckle fracture, the primary cause of the injury is axial loading. This type of fracture typically occurs in pediatric populations when there is a compressive force applied along the axis of a long bone, often seen in falls where a child lands on an outstretched hand. The force compresses the bone, resulting in a deformation that causes the cortex to bulge or buckle on the tension side, while the opposite side remains intact.

Understanding this mechanism is crucial, as it distinguishes torus fractures from other types that may be caused by different forces, such as rotational forces that can lead to spiral fractures, direct impacts causing complete fractures, or traction forces that typically affect ligaments and tendons rather than causing a bony fracture. The unique characteristics of a torus fracture highlight the importance of recognizing the specific forces involved in different types of bone injuries.