This species of hernia is only partially co vered by peritoneum. Dominique Sala is, according to Bartholin,f the first person who mentioned this peculiarity. The reason of this circumstance is obvious : when the bladder is distended, it is raised to the level of the crural arch and of the inguinal ring; it pushes before it the peritoneum, and insinuates.itself between the peritoneum and the abdominal muscles. If at this time a violent effort determine the escape of the corresponding part of the organ by one or other of these openings, it is the Anterior, superior, and lateral part of the organ which will be presented, and this is the portion which is without a peritoneal invest ment; so that at this time the herniae we have described are completely deprived of a sac. It usually happens, however, that the posterior portion of the organ soon follows, dragging with it the peritoneum by which it is covered ; this portion in turn drags down that which is in the vicinity of the ring; and in this way a hernial sac is formed, ready for the reception of the intestine or the omentum. This is the reason why a hernia of the bladder is so fre quently accompanied by an intestinal or omen tal hernia. • It does not appear to be well established whether a primitive hernia of the bladder occurs in the direction of the inguinal canal, or whether it escapes directly through the aponeurotic opening of the external abdominal muscle, though the latter opinion is the most probable. It has been remarked in some cases that the spermatic vessels were external to the hernia.
In consecutive vesical hernia an intestinal hernia primarily exists ; the intestine pushes before it the peritoneum which surrounded the ring, and in proportion as the hernia increases in volume, does the sac augment, the peri toneum in the neighbourhood of the ring is drawn down, and, as a consequence, that which invests the posterior surface of the bladder, which in its turn is also drawn down, if, on the one hand, the adherence of the peritoneum to the bladder be sufficiently strong, and if, on the other, the latter organ be voluminous and sus ceptible of displacement. The primitive peri neal and vaginal herniae are similarly situated as to the non-existence of a hernial sac, and of the existence of consecutive hernia in these situations we have no record.
The species of vesical hernia which is most commonly seen is the inguinal ; the tumour is usually confined to the groin, but it may descend into the scrotum, gliding along the spermatic cord.* Hernia of the bladder at the crural ring is very rare. It presents the same characters and is subject to the same complications as that which occurs at the inguinal ring. Its form and its seat only are different; it is developed at the same point as a merocele, and like it takes a globular form.
Vesical hernia at the perineum is an ex tremely rare disease,' and for some time was supposed to occur exclusively in pregnant women, but the observation of Pipelet is con clusive as to the possibility of its existence in man. In these cases a portion of the bladder passes between the fibres of the levator ani muscle, and it is presented in the form of an ovoid tumour placed at the side of the anus. In each' of the three species of hernia which we have described, the bladder suffers certain changes of form: it is contracted at the level of the opening through which it passes, and is again dilated below this point. This circumstance
has been observed by Keate, Pott, and Ber trandi. Sometimes even calculi have been found in the displaced portion of the blad dent Few occasions have occurred of observing hernia of the bladder through the vagina. In this affection the fundus of the bladder de presses the anterior parietes of the vagina, and forms a round projection, which is frequently visible externally when it passes the level of the orifice of the vulva. The disease is usually developed during pregnancy when pressure is made by the distended uterus upon the neigh bouring organs; but cases have occurred at an advanced period of life. Of all the species of hernia of the bladder, that by the vagina occa sions the most symptoms, and these symptoms are principally owing to the devia tion which is produced in the canal of the urethra, which is drawn downwards and for ward by the fundus of the organ, so as to prevent the passage of the urine along it. In this way a complete retention of urine is pro duced, together with tension, pain and aug mentation of volume in the abdomen, agitation, sleeplessness, sympathetic irritation of the heart and the brain.
Considerable doubt has usually been ex pressed, whether hernia of the bladder is sus ceptible of true strangulation ; whether the sensibility of this organ is of the same na ture as that of the intestines, and whether its constriction might give rise to similar sym ptoms. In the case described by strangulation does, however, appear to have occurred, but the symptoms which he detailed were not well marked. The symptoms given by J. L. Petit t do not appear sufficient to enable us to distinguish strangulation where the bladder is implicated from that in which the intestine suffers. Hiccup, says Petit, pre cedes vomiting in hernia of the bladder, while in intestinal hernia the latter precedes the former symptom. If strangulation should occur, the method of relief proposed by Du rand, viz. to empty the tumour by puncture with a trocar, appears rational.
Inflanzmation.—Inflammation of the blad der may be produced by a variety of causes among them we may mention external violence, incised wounds of the organ, contusions on the hypogastric or perineal region, concus sions of various kinds, the bladder being dis tended, the compression consequent upon pregnancy, upon a laborious accouchement, upon the use of the forceps, upon the pre sence of a pessary or a hernial displacement ; the presence within the organ of foreign bodies, whether introduced from without, generated within, or derived from the kidneys, distention consequent upon retention, and the use of cantharides and certain other diuretic me dicines. It may also be communicated to the bladder by neighbouring organs, such as the kidneys, the urethra, the prostate, the uterus, and the rectum. It may be developed during the progress of acute gastro-enteritis, may succeed to certain articular inflammations, to certain cutaneous affections, and to • the sup pression of a hemorrhoidal or menstrual flux.