Wounds may be defined to be divisions of soft parts, including the skin, produced by external mechanical force. They are generally divided into (1) incised wounds, such as cuts or incisions, including those which remove a portion of the body; (2) punctured wounds, such as stabs; (3) contused wounds, in which the divided parts are bruised or crushed; (4) lacerated wounds, in which there is tearing of the tissues; (5) poisoned wounds, in which some poison or venom is inserted.
Simple, open, incised wounds will be more fully noticed than any of the others, because they have been most fully studied, and in their surgical relations are the most important. In a clean cut, whether made accidentally or in a surgical operation, three things are chiefly to be observed—viz. the opening or gaping by the retraction of their edges, the bleeding, and the pain. The gaping of a wound is caused by the retraction of the various tissues which are divided. Of the various tissues the skin exhibits the greatest degree of retraction, and then (in the order in which they stand) elastic tissue, cellular or connective tissue, arteries, muscles, fibrous tissues, nerves, and cartilages. In addition to the immediate gaping of fresh wounds, many wounds, if they be not prevented, will continue to retract for a long time. For example, in stumps that heal slowly the limb terminates in a cone, in consequence of the prolonged retraction of the muscles. The bleeding from an incised wound depends chiefly on the size and number of the divided vessels, and on their connection with the surrounding parts, but to a certain extent on the previous condition of the wounded part, or on the peculiar constitution of the patient. Gradually, with or without surgical help, the vessels cease to bleed; and then, if the wound be left open, there is an oozing of blood-tinged serous fluid, succeeded gradually by a paler fluid which collects like a whitish film on the surface, known as lymph (see under INFLAMMATION), and contains an abundance of white or colourless blood-cells, imbedded in a fibrinous (and therefore spontaneously coagulating) fluid. The nature of the pain cannot be made clear by any description to those who have not felt it; and it is more than probable that a similar wound inflicted on two or three persons would occasion different degrees of pain in each. There are also differences in both the kind and degree of pain, according to the place and manner of the wound. The skin is more sensitive than the deeper parts; that of the face, hands, and feet more sensitive than that of most other parts of the body. The local consequences of an incised wound are indicative of inflammation. In the course of an hour or more the edges of the wound and the adjacent parts become swollen and abnormally sensitive, feel hot and aching; the sutures (if any have been inserted) become tighter, and the edges and intervening spaces gape in consequence of the swelling. These symptoms gradually subside in two or at least four days, unless there is some abiding source of irritation. Except in very severe wounds, no general consequences are apparent. In these exceptional cases, as in amputations, for example, a Shock (q.v.) and subsequent reaction are observed. The duration of this feverish reaction or traumatic fever does not seem to bear any fixed relation to the severity of the injury. Sometimes it subsides within twenty-four hours; more often, after large wounds, it does not subside for three or four days. If constitutional disturbance should last more than four or five days after the receipt of the injury, there is probably some persistent irritation or some morbid complication.
The healing of open incised wounds may be accomplished, according to most surgical author- ities, in five different ways: (1) Healing by immediate union takes place when the wounded parts being placed and maintained in contact first stick together, and then become continuous, without the formation of any new material as a connecting medium. For example, a flap of skin is raised by dissection in the removal of a tumour or a mammary gland, and is then replaced on the subjacent parts. In three days at most the union may be complete, without any indication of inflammation, there being no evident efflux of blood, no exudation of reparative material, and no scar. (2) In healing by primary adhesion lymph exudes from both cut surfaces, becomes organised, gradually connects the cut surfaces, and at length forms between them a firm layer of connective tissue, covered with a thin shining cuticle. These steps are well seen after the operation for hare-lip, for example. These two methods are known as healing by first intention. (3) Healing by scabbing, or under a scab, is the most natural and in some cases the best of all the healing processes. In animals it is often observed that if a wound be left wide open the blood and other exudations dry on its surface and form an air-tight covering, under which scarring takes place, and which is cast off when the healing is complete. In man this process is less frequent, because, in the first place, exudations seem to be more often produced under the scab, which detach it and prevent the healing; and secondly, surgical interference seldom allows this method to have a fair trial. The first three methods are obviously the most desirable, and should be aimed at whenever it is possible to do so. (4) In healing by granulation or second intention the wound becomes coated over with a film of lymph, which, if the wound be left open, increases, becomes reddened by the development of blood-vessels within it, and is transformed into granulations. We cannot enter into the life-history of these granulations, and can only remark that they are finally developed into a scar consisting of fibro-cellular or connective tissue, with a superficial layer of epidermis. The completion of the healing is accomplished by the gradual improvement of the scar, in which the connective tissue becomes more perfect in its character, and the cuticle becomes thicker and more opaque. (5) Healing by secondary adhesion, or by third intention, is accomplished by the union of two granulating surfaces (e.g. those of two flaps after amputation) placed and maintained in contact.
In the treatment of incised wounds there are four main points to be attended to: (1) Arrest of hæmorrhage, by pressure with the finger or a pad of lint, by cold, or, if arteries of any size have been divided, by their ligature or torsion (see BLEEDING). (2) Removal of any foreign bodies which may have been introduced. (3) Accurate apposition of the sides and edges of the wound by pads and bandages, by plasters, or by Sutures (q.v.), according to the size and position of the wound and the degree of gaping which has to be counteracted. (4) Prevention of decomposition in the wound and its discharges (see ANTISEPTIC SURGERY).
Of the other varieties of wounds it is sufficient to notice the most important points severally peculiar to each variety. Of punctured wounds the most serious are those which are made with blunt-pointed instruments, such as nails, pitch-forks, iron spikes, &c., for by these the injured parts are not so divided as that they may retract, but are pressed aside with much bruising, and can close again as soon as the instrument is withdrawn; and in this lies the chief danger of these wounds, because blood or other fluids are likely to extravasate into them, and cannot readily escape. These fluids, by decomposing or by mere pressure, may excite inflammation, and thus cause deep and confirmed suppuration and great destruction of tissues. Contused and lacerated wounds are much more severe and dangerous than incised wounds of the same size, because the adjacent tissues are bruised and injured, and sloughing is very apt to occur. Such wounds on the limbs, if extensive, often necessitate amputation. If union is to be attempted, the rules given for the treatment of incised wounds must be followed, especial attention being paid to their careful cleaning, the removal of clots of blood, and their warm covering with some soft material, as cotton-wool. In no cases is careful antiseptic treatment at first of more importance or of more signal benefit than in severe wounds of this class. Gun-shot wounds are merely a special group of contused and lacerated wounds, which from their great importance in military surgery have a large literature of their own.
Of poisoned wounds the most important are the bites of Snakes (q.v.) and other venomous reptiles, the stings of insects, the bites of rabid animals (see HYDROPHOBIA), and Dissection Wounds (q.v.). See also VENOMOUS BITES.
In conclusion it must be mentioned that various kinds of wounds are liable to certain complications, of which some are local and others general or constitutional. Among the former are recurring or secondary bleeding, pain, spasmodic muscular movements, and the presence of foreign bodies; whilst the latter include defect or excess of reaction, traumatic delirium, fever, erysipelas, pyæmia, tetanus, &c. Some of these complications are treated of in special articles of this work; and for the treatment of the remainder we must refer to Holmes's System of Surgery, or other standard works.