HERNIA, Definition.—The term hernia is used to denote the protrusion of one or more of the abdominal viscera, and is synony mous with the ordinary term "rupture." Varieties.—If the protrusion occurs through openings in the abdominal wall which, normally patent in foetal life, through some defect in development have failed to close at birth, the hernia is said to be congenital. The protrusion may also occur at other points in the abdominal wall, by nature weaker than elsewhere, namely: in the femoral re gion, in the inguinal canal, and at the umbilicus. In these cases the rupture may be said to be acquired.
In addition to these varieties we have ventral hernia following abdominal in cisions or accidental wounds. This va riety is frequently known as traumatic. A hernia takes its name from the site of the opening through which it protrudes. The common forms are: ingvinal, fem oral, umbilical, and ventral. The rare forms: diaphragmatic, lumbar, obturator, ischiatic, pudendal, perineal, properito neal, and retroperitoneal.
Distinction is often made between ex ternal hernia, including all the varieties above mentioned, and internal hernia, by which latter is meant the protrusion of a viscus through some anomalous pouch in the peritoneum.
Surgical Anatomy.—A hernia consists of a sac, the coverings of the sac, and contents. The sac is always a prolon gation of the parietal peritoneum; it varies in size and shape according to the stage of the hernia. At first it is merely a pouting or bulging into the hernial fice; narrow at the end, wide at the base.
As the hernia extends and emerges from the orifice, the sac is elongated, and from the pressure of the contents the lower portion becomes globular or pyriform in shape. The narrowest part of the sac is called the neck, and the external, or distal, portion is called the fundus. A sac formed in this way—namely, by a gradual pushing forward of the parietal peritoneum—is said to be acquired, while a congenital sac is preformed, the pro trusion occurring in the open tuniea vaginalis or through the patent navel. A congenital hernia, while it may appear late in life, is dependent upon conditions which existed at birth.
Adhesions may occur between the sac and its contents. The sac may become
greatly thickened and opaque,—usually owed to the irritation of an ill-fitting truss,—and may undergo calcareous or malignant degeneration. Certain her nias are said to have no sac,—as, for stance, hernia of the bladder, sigmoid flexure, or cmcum. This is not entirely true; a sac exists, but the peritoneum does not completely surround the viscus.
The coverings of the sac are made up of the different layers of tissue outside of it. These, of course, vary according to the site of the hernia. An accurate knowledge of these layers is becoming more and more necessary to the surgeon, owing to the increasing importance given to modern methods for radical cure.
(See Colored Plate.) Every viscus, except the pancreas, has been found in some variety of hernia. Three eases of ovarian hernia. l3oth of the first two eases, in children, were evidently congenital. The third ease. the patient a woman of 40 years. was pregnant for the ninth time, had a pain ful tumor in the right inguinal region, which had existed nine years, during which time she had suffered from gas tric disorders and constipation. At the operation the sac was found to contain the right tube and ovary. These cases all gave a percussion-note over the lump instead of the intestinal tympanic note. Quadflieg (Mfinchener med. Woch., May, 1901).
Review of 180 cases of hernia of the urinary bladder collected from literature and a report of a personal case. It is mainly due to direct traction upon the organ by the hernial mass, or on the sac during operations for radical cure. It is sometimes possible during operation to recognize and avoid injuring it, espe cially if after one hernial sac has been found any structure resembling a second sac is regarded as bladder, until exami nation will have shown that it is not. Immediate suture with two layers of catgut and closure of the hernial wound by Bassmi's method is the best step, if the bladder is injured. A small drain must be left leading to the bladder suture-line. It caused death in about 10 per cent. of the hernia cases which it complicated. W. S. Cheesman (Med. Record, June 22, 1901).