(From Hernia 4168 a branch, because it protrudes forward). A tumour, ecrexis ramex, and a rupture, as occasioning a tumour. In consequence of some sudden effort, a portion of the contents of some cavity is forced through the interstices of the containing parts, usually confined to the abdominal contents forced through the interstices of the abdominal muscles, or those openings designed for the passage of nerves and blood vessels. Dr. Cullen defines it an ectopia, or displacing of a soft part, though still covered with the skin and other integuments.

From the situation of these tumours, their contents, or both, they obtain their respective denominations; occasionally taking their name from attending circumstances. 1. Those from the situation are the umbilical, femoral, labial, scrotal, or ventral. 2. Those from the contents are the enterocele, epiploccle, entero-epiplo-cele, pneumatocele. 3. Those from attending circumstances are, the incarcerated hernia, etc. True and false hernia have been distinguished; but each is a tumour of the scrotum, and the former are from the abdominal viscera, beginning from above and descending downwards to the groin or scrotum; while the latter begin from below and ascend upwards; as the hernia hu-moralis, hydrocele, haematocele, and sarcocele. These are diseases in the part where the tumour appears; from the Greek term Hernia 4169

The inguinal is the most frequent hernia; and the next to this is the femoral. The umbilical seldom occurs except in elderly women, who have been often mothers. A hernia of any other viscus, besides the intestines, is peculiarly rare.

When the intestines fall down from the cavity of the abdomen, or rather of the peritonaeum, it is evident that this latter membrane must be carried with them, unless it should be ruptured or wounded, which is seldom the case. When independent of wound, the gut usually falls through those apertures, originally formed for the passage of the spermatic cord; and in women of the round ligaments of the uterus, or for the femoral arteries. These apertures are imperfectly closed with fat only; for they are not muscular, and therefore do not admit of contraction. It sometimes, however, happens that the intestine is forced through the fibres of the abdominal muscles; and one case is recorded in which the colon was pushed through the fibres of the diaphragm; in others, the intestines have passed by the side of the oesophagus, by the vena cava inferior, or more rarely ' by the aorta into the thorax; the general cause is whatever contracts the capacity of the abdomen, or violently forces the intestine against the apertures mentioned. Violent coughing, crying, laughing, coetiveness, dysury, pregnancy, or whatever produces a deep inspiration, occasions this contraction, by the united exertions of the diaphragm and abdominal muscles. Suddenly lifting a heavy weight, which produces a deep inspiration, the jumping of a rough horse, and any other violent exertion, have been followed by the same consequences. Independent of these causes, in weak persons the weight of the intestines will produce a similar effect. It is, therefore, common in warm climates; after long fevers in old persons; those who, with poor diet, have laboured hard; and it has been said, that those who eat large quantities of oil are subject to this complaint. This, however, can scarcely happen but in the warmer regions; and increased temperature alone predisposes to it. Hernia sometimes appears to be hereditary.

There are other apertures through which the intestines sometimes, though very rarely, pass; as between the bladder and rectum, or the uterus and rectum, when the tumour appears in the perinaeum; by the is-chiatic notch; or by the side of the sciatic nerve, when they are seated under the glutaei muscles. Mr. Cooper mentions a singular hernia, where the intestine passed into the labia pudendi, falling; under the branch of the ischium along with the internal pudendal artery, but continued into the pelvis, by the side of the vagina. In one case they passed between the laminae of the peritonaeum into the mesentery; and, in another, into a bag formed by a separation of the laminae of the mesocolon. When the formation of the muscles is defective, the intestines may even protrude at the loins.

Other viscera are occasionally displaced. The brain is sometimes protruded through the skull, when the bones of the head are deficient; the lungs will occasionally pass through the fibres of the intercostal muscles; and the uterus or bladder has been protruded through the parietes of the abdomen. These herniae are, however, uncommon.

The sac which contains the intestines is, therefore, the peritonaeum, and the contents are most commonly the omentum and the ilium; less frequently, in succession, the colon, the coecum, and the jejunum: sometimes only the appendix caeci vermiformis. The peritonaeum in this situation is generally thickened; though, when the weight has been considerable, it has been found peculiarly thin. The rupture of the peritonaeum, which was supposed always to happen, and which gave a name to the disease, rarely occurs. The sac, however, has occasionally burst, particularly in one instance, by a blow; and where the intestines escape, from defective organization of the muscles, they are seldom in a sac, for the peritonaeum also is usually de fective in the corresponding portion. The hernia congenita and hernia cystica are equally destitute of the peritonaeal covering; and, in one instance, the umbilical hernia was without it, a circumstance which should suggest extreme caution in the operation. The size of the sac differs from different circumstances, chiefly from the duration of the disease. The symptoms, however, are not in proportion to the size. We have seen the most violent ones occasioned by a rupture not equal in size to a filbert.