Causes

How do fractures of the shoulder commonly happen?

Various forces can cause fractures and dislocations of this region including avulsion, impact, bending, and twisting. The result of impacts clearly will depend on the point of contact. By contrast, twisting injuries tend to damage the weakest part of the linked system. Bending forces such as falls may also be transmitted up the system so a fall on the outstretched hand commonly causes a fracture of the neck of the humerus.

Traction on the arm is a rare but significant cause of injury to the shoulder. A rodeo bull rider binds his hand to the strap round the bull. If he is thrown and the hand remains trapped, the whole weight of the body may be thrown around by the bucking animal. All of this force is transmitted through the shoulder causing fractures, dislocations and nerve injuries.

Open fractures where the bone fragments are contaminated by an open wound are not particularly common in this region. This type of open fracture can be caused by stab wounds, major lacerations, or gunshot wounds.