1. It appears that fracture of the humeral shaft occurs more often in persons over fifty. This incidence corresponds with that found in a study carried out by the Pennsylvania Orthopaedic Society in 1959.
2. The middle third of the bone is the most vulnerable portion of the shaft, where transverse fracture and radial nerve palsy most commonly occur.
3. Most fractures of the shaft of the humerus are best treated by simple splintage. The degree of radiological deformity that can be accepted is far greater than in other long bones. In this group anterior bowing of 20 degrees or varus of 30 degrees was present before it became clinically obvious and even then the function of the limb was good.
4. Internal fixation is only occasionally indicated but operation on the middle third of the bone increased the chances of delayed union.
5. In the treatment of delayed union intramedullary fixation and the application of slivers of iliac bone is effective in stimulating the fracture to join.