1. The frequency and types of deformity common in fractures of the proximal end of the humerus are tabulated according to Kocher's classification, which should be revived in the interest of accuracy and clinical usefulness.
2. Anatomical factors leading to the production of the low subtubercular fractures peculiar to the first decade of life are discussed. These fractures deserve recognition as a separate type peculiar to this age group.
3. The fact that epiphyseal separation of the proximal humeral epiphysis occurs during the second decade in life is emphasized and factors giving rise to it are discussed.
4. By the use of a phantom model the qualitative action of the muscles of the shoulder joint can be studied and expressed in graphic form.
5. The phantom model is of service in a study of methods of fracture reduction and enables one to determine graphically and by the use of motion pictures anatomical factors that are of value in clinical application.
6. The assumption that in fractures of the upper end of the humerus one must dress the long fragment in line with the short fragment, over which one has no control, is erroneous. One has control of the short fragment by virtue of the long head of the biceps bridging the fragments, and the remaining untorn periosteum.
7. It is emphasized that, when the arm is abducted, the pull of the adductor muscles makes approximation difficult to obtain and still more difficult to preserve. Clinical experience bears this out.
8. Accurate approximation can be obtained and maintained by downward traction, a fact demonstrated on the phantom model and by clinical experience. The integrity of the long head of the biceps tendon is necessary for the use of this method.
9. A simple method of reduction under local anaesthesia for fractures of the upper end of the humerus is described. This method makes possible the use of ambulatory treatment without splinting.
10. By adequate after-care function is restored almost as soon as bony union is complete; and a painless, useful joint is regained.