Hernia (Lat.; probably from Gr. ernos, 'a sprout'), in its widest sense, signifies a protrusion, though an abnormal or accidental opening, of any organ from its natural cavity. Although hernia may occur in many parts of the body, the word, used by itself, is restricted to signify protrusion of the abdominal viscera, the condition popularly called rupture.
The way in which hernia may arise will be readily understood if we bear in mind that the abdominal viscera are subject to constant pressure from the diaphragm and other surrounding muscles. If at any point the walls of the belly are not sufficiently strong to resist this pressure some portion of the viscera is driven through them, and a hernial tumour is formed. Certain parts of the abdominal walls, especially the inguinal and crural rings, and the umbilicus, being weaker than others, hernia most frequently occurs at these points. In some instances hernia is congenital, from abnormal deficiency of the walls; in other cases it may arise at any period of life as a result of violent bodily exertion. Sex, age, and occupation seem to have a marked influence in predisposing to hernia. Men are far more liable (in about the proportion of four to one) to this disease than women; though they are less so to those forms of the affection known as femoral and umbilical hernia. According to Malgaigne, in France one man in thirteen, and one woman in fifty-two, are the subjects of hernia. In respect of age he found that the liability is least about the age of thirteen (one in seventy-seven), after which it progressively increases until the close of life, rising at seventy to seventy-five to one out of every three.
A hernia is almost always composed of a sac and its contents. The sac is a portion of the Peritoneum (q.v.) corresponding to the aperture at which the hernia protrudes. It is pushed forward by the protruding viscera, and forms a pouch. The contents vary greatly, but generally consist of a portion of the small intestine (particularly of the ileum), forming the variety of hernia known as enterocoele. Omentum is often found in hernial sacs, either with or without intestine. Besides the viscera, the sac always contains a certain quantity of fluid secreted by its interior. Hernia is divisible (1) into reducible, or returnable into the abdomen, irreducible, and strangulated; and (2), according to its situation, into inguinal, femoral, &c.
The treatment of reducible hernia may be palliative or radical. The palliative treatment consists in the application of a truss (see below) to retain the protrusion within the cavity of the abdomen. Each particular kind of hernia (femoral, umbilical, &c.) requires its special form of truss; and before applying it the hernia must be reduced by placing the patient on his back, relaxing the muscles by bending the thigh upon the abdomen, and pressing the tumour back in the proper direction. The truss should then be put on, and should be worn during the whole of the day; and if the patient will submit to wear it (or a lighter one) during the night, so much the better. The means that have been contrived to effect a radical cure are too purely surgical for description in these pages. Below the age of puberty, and if the hernia is recent, a radical cure is sometimes effected by wearing the truss for two or three years.
In irreducible hernia the protruded viscera cannot be returned into the abdomen, but there is no impediment to the passage of their contents or to their circulation. In these cases the patient is often liable to dragging pains in the abdomen, and to attacks of vomiting, in consequence of the movements of the abdominal organs being checked by the omentum or intestines being fixed. There is also constant danger of this hernia passing into the strangulated form. The treatment may be either palliative or radical. The palliative treatment consists in the employment of a truss with a hollow pad that shall embrace the hernia, and prevent any additional protrusion. An irreducible hernia may sometimes be converted into a reducible one by keeping the patient in the recumbent position, and on very low diet, for two or three months; at the same time keeping the bowels open by laxatives and injections, and maintaining equable pressure over the tumour. Radical cure is, as in the case of reducible hernia, by operation.
Hernia is said to be strangulated when a portion of intestine or omentum that is protruded is so tightly constricted that it not only cannot be returned into the abdomen, but has its circulation arrested. This form is highly dangerous, because, if relief is not speedily afforded, the strangulated part becomes gangrenous. The causes of strangulation are various, but this condition most commonly arises from a sudden violent effort, by which a fresh portion of intestine is driven into a pre-existing hernia, which it distends to such a degree as to produce this complication. The most prominent early symptoms are flatulence, colic pains, &c. They are succeeded by vomiting first of the contents of the stomach, then of mucus and bile, and lastly of fecal matters, owing to inverted peristaltic action. If relief is not obtained the inflammation that commences in the sac extends to the peritoneum, and the ordinary signs of peritonitis appear. After a variable time comes gangrene or mortification of the part, and the patient speedily sinks.
The surgeon first tries to return the intestine, as in the preceding cases. This manipulation, termed the taxis, may be assisted by the internal use of chloroform, inhaled till it produces complete relaxation of the muscles, by the hot bath, &c. If this fails he must have recourse to the knife to divide the constriction.
The necessity of having recourse to a suitable truss the moment that the slightest protrusion shows itself in any of the parts liable to hernia cannot be too strongly urged as a matter of necessary general knowledge. At whatever period of life a hernia occurs, if properly attended to and judiciously supported, it usually gives little trouble, and if it occurs in early life, it may often be cured; whereas, if it be neglected, increase of bulk, and, subsequently, diseased states of the parts, often terminating in death, will almost certainly occur. A truss consists essentially of a pad or cushion attached to a metallic spring, with straps so arranged that its position may be retained during the varied postures of the body. A surgeon should always be consulted in the choice of the instrument. 'The practice,' says Mr Birkett, 'of leaving cases of rupture in the hands of mere tradesmen cannot be too strongly censured. Amongst the poor we constantly observe the lamentable effects of this proceeding.' Many varieties of trusses have been invented. There are occasional cases in which the common truss fails to support a rupture comfortably, and in these cases various instruments, for the most part the property of special instrument-makers, are often serviceable. The patient must expect to find the truss somewhat uncomfortable for a week or two, but will soon get used to it. The skin of the part upon which it presses should be regularly washed and bathed with eau de Cologne or spirit, as, without this precaution, boils are apt to form on it.