(25) Comminuted Fracture of the Humerus
Range '50 yards.' Velocity extreme.
Impact somewhat oblique. The bullet entered anteriorly about 3 inches above the elbow crease. The wound of exit was on the inner aspect of the arm and explosive in character; it still measured 4 inches by 2 inches three weeks after the injury was received.
The wounds suppurated locally, but at the end of six weeks fair union of the bone had taken place and the wound of exit had contracted to a sinus. The musculo-spiral nerve was concussed, but not divided.
The skiagram was taken three weeks after the reception of the injury.
Comparison with plate IV. demonstrates the effect of high velocity in free comminution of the bone, the sharper radiation of the stellate lines of fracture, and the propulsion of bone fragments.
The bones of the forearm were also often fractured. The principal peculiarity of these fractures was the common localisation of the injury to one bone, which is readily seen to be probable.
Each bone offered some special features dependent on its structural character and anatomical position. In the case of the ulna, pure perforation of the olecranon process, without obvious evidence of implication of the elbow, was seen on several occasions. The other important feature with regard to this bone depends on its subcutaneous position, which accounted for the frequency with which highly developed explosive exit wounds were met with. One is figured in the general section (fig. 47, p. 156). This, however, is a very slight instance compared with what was often seen in the upper and middle thirds of the bone, where the lateral soft parts often protruded as a much larger tumour, the particular illustration being mainly designed to show the nature of the injury to the skin. The radius, as more deeply placed in the upper part of its course, was less often the seat of such well-marked explosive injuries; but when the lower end was struck this character was sometimes very striking: thus in a track passing antero-posteriorly through this bone, the whole lower end appeared shattered, all the tendons at the back of the wrist being implicated in the protruding mass, while the bone itself seemed shortened, so that the hand took up the position common in Colles's fracture. It was found impossible to place the bone in good position; nevertheless the patient retained his hand, which is still of use in writing.
Plate X. is a good example of a high-velocity injury in which lateral contact with the radius has produced local comminution, some slight injury to the casing of the bullet, and the separation of a large wedge. The case from which this was taken also illustrated well one of the chief troubles of such fractures of the forearm; the degree of splintering resulted in the formation of a large mass of callus, which for a time rendered any degree of pronation and supination impossible.
