Fractures of the proximal humerus (ball) account for 5-15 % of all fractures. Majority of these occur in elderly individuals with osteoporosis, and are a cause of major morbidity. In younger individuals, these fractures occur after high-velocity trauma.
Indirect injury to the shoulder occurs during a fall on outstretched hand from standing position. Direct blow to the shoulder may also cause these fractures. In motor vehicular accidents, these injuries may coexist with several other fractures. Electric shocks and convulsions are other mechanisms.
The proximal humerus (ball) consists of three parts: L=lesser tuberosity, G=Greater tuberosity, H=humeral head. Arrow shows the junction between the ball and the shaft, called the surgical neck. The neck is a frequent site of fracture.
Arrow shows the axillary nerve that is frequently damaged when a fracture in this region occurs.