Proximal humerus fractures.

Proximal humerus fractures are common injuries. Knowledge of local anatomy is paramount in the evaluation and treatment of these injuries. Information regarding humeral head vascularity, fracture patterns, bone quality, and overall geometry have direct implications for nonoperative treatment, internal fixation, and hemiarthroplasty. The ascending branch of the anterior circumflex artery perfuses most of the humeral head. When fractured, the greater tuberosity tends to displace posterosuperiorly, the lesser tuberosity and the shaft displace medially, and the head may be pulled by the attached tuberosity, impacted into valgus, or in more severe cases dislocated, impacted, or divided. Internal fixation of two-part, three-part, and selected four-part fractures may be compromised by local osteopenia; knowledge of the location of the strongest bone in the proximal humerus combined with the use of fixed-angle devices and occasionally bone graft or substitutes has improved the outcome of osteosynthesis. When the humeral head cannot be preserved, successful hemiarthroplasty requires tuberosity union and anatomic restoration of the overall geometry of the proximal humerus in terms of height, retroversion, and head-tuberosity relationships. Copyright 2006 Wiley-Liss, Inc.