STRUCTURE OF THE ELADDER. 423 



angle in ■which the obliterated hypogastric artery lies. The superior 

 false ligament (ligamentiim snspeusoriiim) is the portion of peritoneum 

 between the ascending parts of the epigastric arteries, and reaches 

 from the summit of the bladder to the umbilicus. 



Interior of tlie "bladder. — On opening the bladder, its internal 

 surface is found to l)e lined by a smooth membrane, which is compara- 

 tively loosely attached to the other coats, so that in the empty con- 

 dition of the organ it is nearly everywhere thrown into small wrinkles 

 or ruga3, which disappear as soon as the bladder is distended. Besides 

 these, the interior of the bladder is often marked by reticular elevations 

 or ridges, corresponding with fasciculi of the muscular coat. 



At the lower and anterior part of the bladder is seen the orifice 

 leading into the urethra, around which the mucous membrane is corru- 

 gated longitudinally. Immediately behind the urethral opening, at 

 the anterior part of the fundus, is a smooth triangular surface, 

 having its apex turned forwards, which, owing to the firmer adhesion 

 of the mucous membrane to the subjacent tissues, never presents any 

 rugse, even when the bladder is empty. This surface is named the 

 trigone (trigonum vesica), Lieutaud) ; at its posterior angles are the 

 orifices of the two ureters, situated about an inch and a half from each 

 other, and nearly the same distance from the anterior angle, where the 

 bladder opens into the urethra. 



The orifices of the ureters, presenting the appearance of oval slits, 

 are directed obliquely forwards and inwards : they are united by a 

 curved elevation, convex forwards, which extends generally outwards and 

 backwards beyond them, and which corresponds in position with a 

 muscular band which joins them together and to the neck of the 

 bladder. Proceeding forwards from opposite the middle of this, is 

 another slight elevation of the mucous surface, named the vvida rcsicce 

 (luette vesicale), which projects from below into the urethral orifice. 

 In the female, the trigone is small, and the uvula indistinct. In the 

 male the uvula lies a little iii advance of the middle lobe of the 

 prostate, and is sometimes prolonged on the floor of the prostatic portion 

 of the urethra. It is produced by a thickening of the submucous tissue. 

 In its natural state this may contribute to the more perfect closure of 

 the orifice of the bladder ; when enlarged by disease it frequently pro- 

 duces serious obstruction at the commencement of the urethra. 



STRUCTURE OP THE BLADDER. 



The bladder is composed of a serous, a muscular, and a mucous coat, 

 united together by areolar tissue, and supplied with numerous blood- 

 vessels and nerves. 



The serous or peritoneal coat is a partial covering, investing only 

 the posterior and upper half of the bladder, and reflected from it upon 

 the surrounding parts in the manner already described in detail. 



The muscular coat consists of unstriped muscular fibres, so ar- 

 ranged as to Avarrant the usual description of them as forming layers, 

 the outer of Avhich consists of bundles of fibres more or less longitudinal, 

 and the next of fibres more circular in disposition ; while beneath this, is 

 another delicate longitudiual layer more recently recognised. 



The external or JonijituiUnal fibres (fig. 306, A, a, B, h, and fig. 307) 

 are most distinctly marked on the anterior and posterior surfaces 

 of the bladder. Commencing in fi'ont at the neck of the organ. 



