PART IV.
INJURY AND REPAIR.
CHAPTER XXI.
WOUNDS AND THEIR REPAIR.
The old classification of wounds divides them into contused, lacerated, punctured, and incised. For descriptive purposes these adjectives are self-sufficient; they can be criticised only in case the injuries differ in character. The adjectives thus employed allude to the character of the injury as well as to its cause, but no meaning should be conveyed by any of them other than to indicate a severance of continuity in tissues. In either case cells are rudely torn apart. But whether the injury be subcutaneous and the tearing make a ragged surface; or whether the wound be an open one, with the possibility of introduction of germ-laden air and grosser impurities, even though the surfaces separated present an even plane, as in an incised wound; or a channel or tunnel, as when made by a pointed instrument or a gunshot missile, the principle is the same, and the same processes of repair are brought to work to undo the harm. There is but one natural method of repair, and that includes the exudate, or the utilization of the fluid portion of the blood already poured out, and the activity of cells, those which lie in the vicinity and those which are furnished from a distance, i. e., leukocytes and wandering corpuscles. It is of advantage to have the injury subcutaneous and protected from contact with the air, yet extensive injuries of this kind are often much longer in healing than those inflicted by the surgeon’s knife, when the parts can be brought into complete apposition with each other by sutures.
It is the writer’s intent to simplify the description of the healing processes and to insist that it is always the same, not modified in character but in duration and extent, according to the nature of the injury.
CONTUSION.
The term contusion implies a subcutaneous injury of varied extent, in which laceration cannot be left out of consideration. Even in the mildest contusion mechanical harm has been done, permitting a dilatation of the vessels and the escape of fluid. Should this occur in linear form, as by a whip-lash, there may be what is called a wheal. In loose tissues swelling occurs more easily, as in the eyelid, the scrotum, etc. Injuries of severity will produce laceration, at least of capillaries if not of arterioles, and the result is the escape of an amount of blood which will infiltrate the surrounding tissues and discolor them and produce an extravasation or ecchymosis. The blood barely escapes and coagulates before its absorption begins. The fluid portion disappears before the solid, and the pigment is usually the last. There results a black and blue spot; the color when near the surface is at first indigo or purple, and fades out through bluish and greenish tints into a yellow, which may not disappear for two or three weeks. Should blood collect in a cavity or in large amount the mass is called a hematoma; this is especially common in the pelvis and in the cranial cavity. Should a vessel wall give way from weakness caused by disease instead of by accident the result is the same.
Contused wounds of the surface often cover excessive and even fatal injuries within, as when a heavy object falls upon or injures the abdomen or a limb. The skin is resistant, and the writer has seen a limb pulpified by being run over by a heavy car, the skin being but slightly torn. In such accidents exploratory incisions are imperative. Better results will follow opening the abdomen in cases of severe contusion, for the purpose of exploring the viscera, than will follow the “let-alone” policy of waiting for something serious to appear.
An outpour of blood should be expected in every contusion, save the most trifling, while clot formation may ensue. Whether the clot will be absorbed or require the aid of the surgeon will depend upon its size, its location, and its liability to infection. Clot in some locations, e. g., pressing upon the brain or spinal cord, may justify extensive operation for its removal.
Pain produced by contusion is variable. When nerve trunks of considerable size have been injured pain is frequently aggravated. In general it is proportionate to the amount of swelling, i. e., to the density or laxity of the injured tissue. When exudate occurs beneath unyielding membranes, for instance the periosteum and the capsules of certain organs, the pain may be severe. The appearance of discoloration is proportionate to the depth of the injury and the amount of hemorrhage. The time of its appearance will depend upon the distance from the surface; after fracture of the neck of the femur it may not be observed for several days. The general condition of the patient will depend greatly upon his temperament. When there has been considerable extravasation the release of the fibrin ferment may produce a mild rise in temperature.