THE URINARY BLADDER IN MAN is deeply seated in the anterior inferior part of the pelvis : it is composed of different tissues, membranous and muscular, both calculated to yield and to expand to a slightly distending force, so as to form a recipient reservoir, while the latter is fitted by its contractile power to obliterate the cavity of the organ, and forcibly to eject its contents. This musculo-membranous viscus demands the particular attention of the surgical anatomist, not merely as to its structure, but as regards its situation and connections, as it is the seat of many very severe and often fatal morbid affections, several of which admit of a perfect cure, and most of considerable relief, from operation and from various kinds of local treatment, the safe performance and judicious application of which greatly depend on a cor rect knowledge of the structure and relations of the organ. We propose first to consider the form and structure of the bladder in the normal state, and afterwards to describe its situation and connections.
figure of the bladder must vary according to its state of contraction or distention, in reference to which it is usual to consider it under three conditions, viz. the empty or contracted, the full or ordina rily distended, and the over-distended. Its figure in these different states also varies ac cording to the sex and age of the individual, the bladder of the infant differing materially from that of the adult, and that of the adult female from that of the male ; the bladder of the embryo also differs from that of the fully developed foetus. The younger the animal, the more does its form resemble that of inferior animals, and it is an organ very fully developed in the young of all animals who possess it. This organ, m the adult male, when empty or contracted, is a flattened triangle, the transverse and vertical axes being considerably greater than the antero-posterior one; in this con dition the bladder is buried deep in the pelvis, behind and partly below the symphysis pubis; the base of the triangle is in front of but not very closely applied to the rectum, unless the cavity of the latter be fully distended. When the bladder is expanded in the adult male to that moderate degree which in perfect health usually excites a slight feeling or desire to void the urine, and when the quantity accumulated may amount to half a pint or upwards, its figure is then somewhat oval, its vertical axis being considerably greater than either the transverse or the antero-posterior, the two latter being then nearly equal. The larger end of
this ovoid sac rests inferiorly and posteriorly on the rectum, and is of an irregular form ; the smaller end, which is more regularly sphe roidal, is directed upwards towards the abdo men, and somewhat forwards, and occasionally also a little towards the left side. When the bladder is over-distended from any cause, it becomes considerably increased in every dia meter; it first expands in its lower and middle portions, until the pelvic parietes resist ; it then enlarges superiorly to an indefinite degree, and at the same time the whole organ rotates a little forwards by its- superior, and a little backwards by its inferior fundus. Its figure in this over-distended condition is not merely enlarged, but it also presents a totally different, or rather a reversed shape : the larger extremity of the oval is now superior, occu pying the hypogastric region, which it ren ders prominent and tense in a degree propor tioned to its distension. These observations as to the form of the bladder will not apply in every instance, as occasionally this viscus pre sents irregularities both in size and shape, as well as in the density and delicacy of its tunics. The bladder in the female child does not differ from that of the male of the same age, but in the adult of each sex it presents peculiarities. In the contracted state it is nearly similar in each, only somewhat flatter in the female. When distended, in the latter it presents a more triangular form, the sides somewhat rounded, than it does in the male, where the ovoid form prevails; in the female its lower fundus admits of greater lateral extension in conformity with the shape of the pelvis, and its transverse axis is longer in proportion than in the male ; hence it assumes the triangular more than the oval figure. This character is more remarkable in the female who has borne children than in the virgin ; in the former the bladder, when dis tended, appears to exhibit the effects of the pressure of the uterus posteriorly, and of the pubes anteriorly, being flattened in each of these aspects : in some instances it resembles a small barrel placed tranversely.