Complex fracture patterns of the proximal humerus can be difficult to understand and to treat. Classification systems are inadequate and the exact mechanisms of injury are obscure. From inspection of 73 cases of proximal humeral fractures culled from a large number of museum specimens, we propose a hypothesis as to the nature and configuration of these injuries. It is suggested that the glenoid is the “anvil” upon which the humeral head is broken and that the particular fracture personality reflects the position of the head vis a vis the glenoid at the time of injury. From this perspective, proximal humeral fractures present in a comprehensible and progressive sequence. Five different fractures patterns are identified and account for the vast majority of these injuries. X-ray examination, especially CT 3-D reconstructions, in a small group of clinical cases (30 patients) substantiated the usefulness of looking at these fractures in this way. From a combination of the museum studies and patient material, we have constructed a “fracture wheel” diagram for the presentation of these injuries in a format which may be helpful in organizing a new and clinically useful classification system.