Penetrating Wounds of the Chest.

The immediate effects depend on the size, shape, type, velocity and track of the missile. A high velocity rifle or machine-gun bullet entering the chest through an intercostal space and making its way out through a posterior space may occasion, apart from the initial shock, little disability and with luck no complications. A small more slowly moving vulnerant may produce a punctured wound such as seen with a knife-thrust or driving in of a rod in a car accident. The severity of such a wound will depend on its site and depth and the amount of visceral injury. When a high velocity bullet strikes a rib on entry, the fragments of bone are driven in and cause extensive laceration of lung; the exit wound is large, torn and ragged. Impact of the missile on to rib may produce considerable deflection of its course with the result that the bullet may make its exit or be lodged in most unexpected places. Shrapnel or high explosive fragments which have a lower velocity on impact often remain lodged in lung or other tissue. The most dangerous type of wound is one produced by a relatively slow moving, ragged shell or bomb fragment which, assuming that the wound is not immediately fatal may lay the train for serious pulmonary and pleural infections. The gravity of this form of injury can be emphasised by the statement of Duval who found that the mortality of shell wounds it the last war was eight times that of rifle wounds. Unfortunately, too, wounds are not always single, nor are they restricted to the thorax alone; abdomino-thoracic injuries are frequent and necessarily include injury to the diaphragm.