File:The anatomy of the human body (1844) (18169019806).jpg

Title: The anatomy of the human body
Identifier: anatomyofhumanbo00cruv (find matches)
Year: 1844 (1840s)
Authors: Cruveilhier, J. (Jean), 1791-1874; Pattison, Granville Sharp, 1791-1851; Madden, William Herries
Subjects: Human anatomy; Anatomy
Publisher: New York, Harper & Brothers
Contributing Library: Univ. of Mass Medical School, Lamar Soutter Library
Digitizing Sponsor: Boston Library Consortium Member Libraries

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THE BLADDER. 443 are so large, that they form pillars, which project into the interior of the bladder. The mucous membrane not unfrequently becomes insinuated between these columns, so as to form cells, or what is termed sacculated bladder. The base of the bladder presents three openings, viz., the orifices of the two ureters (r r,fig. 182), and the opening into the urethra. These three openings occupy the angles of an equilateral triangle (" colli- cula ab ureteribus ad urethram producta," Haller), the sur- Fig. 182. face of which is smooth and white, and is always devoid of wrinkles or columns. This is the trigone of the bladder, or trigone of Lieutaud, which has been supposed to possess a pecuhar degree of sensibility. The posterior border (r r) of this trigone is more or less prominent in different individ- uals, and is formed by a line stretching between the orifices of the two ureters ; this prominence is prolonged outward on each side by the portion of the ureter which lies in the parietes of the bladder. It has been stated incorrectly, that the trigone is formed by the projection of the prostate, for it exists in females as well as in males, though it is less prom- inent than in the former. All that part of the base of the bladder which is behind the trigone is generally called the has fond, or inferior fundus.* Most anatomists follow Lieutaud in describing, under the name of uvula vesicce, a tubercle which arises from the low- er part of the orifice of the urethra, and partially fills up that opening; but it exists only in cases of disease, being the re- sult of hypertrophy of the middle portion of the prostate, de- s«;ribed by Home as the middle lobe. The orifices of the ureters are so constructed as to per- mit the easy passage of the urine into the bladder, but com- pletely to oppose its reflux. Their long oblique course be- neath the mucous membrane before opening into the blad- der explains this arrangement. The raised and reflected portion of the membrane might be called the valve of the ureter. The opening of the urethra, which is also called the neck of the bladder, is habitually closed, and, as it were, corrugated. Some force is required in order to overcome the resistance offered by it; the crescentic form which has been attributed to it is not very evident. Structure.—The bladder has three coats : a peritoneal, which is incomplete, a muscu- lar, and a mucous coat; these are connected by layers of cellular tissue : it has also ves- sels and nerves. The peritoneal coat covers the posterior and lateral regions, and the inferior fundus of the bladder. The anterior region, and that part of the base which is in front of the infe- rior fundus, are not covered by it. It is united to the muscular coat by very loose cellu- lar tissue. The muscular coat is formed of interlacing fibres, the direction of which it is, at first sight, very difficult to determine.! This coat is very thin, and does not form a continu- ous layer in enlarged bladders ; but in small and contracted bladders it is continuous, and consists of several layers, and may even acquire a'-thickness of eight or ten lines from hypertrophy. It is, then, very easy to determine the direction of the fleshy fibres, which seem to form a number of layers. The external layer consists of longitudinal fibres, all of which proceed from the neck of the bladder, and expand over the whole sur- face of the organ ; the next layer is formed of circular fibres, some of which are irregu- larly interlaced, while the others are parallel. The regular circular fibres are most nu- merous opposite the inferior fundus of the bladder, and are continuous with the annular fibres of the neck. The irregular circular fibres are most common in the posterior region of the organ. In the situation of the trigone, the muscular layer consists of transverse parallel fibres, pla- ced near each other, and forming a perfectly regular plane. The transverse thick bun- dle stretching between the orifices of the ureters has been regarded by Sir C. Bell as the muscle of the ureters. Its contraction, by enlarging their orifices, will facihtate the entrance of the urine into the bladder. The term sphincter of the bladder is applied to a muscular ring, which is continuous with the circular fibres of the body of the bladder, and is situated at the opening of the urethra. The vagueness and disagreement in the descriptions of this sphincter suffi- ciently prove that no very distinct structure of the kind exists at the neck of the blad- der. Winslow describes some fibres arising from the ossa pubis, and embracing the * It is not uncommon to find the bladder forming behind the trigone a deep cul-de-sac, which I have seen insinuated between that part and the rectum. + (These fibres belong to the involuntary class, the microscopic characters of which are described in the note, p. 323,)
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