THE BLADDER 



101'.) 



outer principally longitudinal, a middle chietly transverse, and an inner jjlexiforni, 

 l)Ut tending towards the vertical din^ction. The lil>res of the outer layer are most 

 distinctly longitudinal on the anterior and jjosterior surfaces, and extend altove 

 along tlie urachus, but they run ohlicjuely over the sides of the l>ladder, decus- 

 sating with each other in a coni])lex manner; and near the urethral end of the 

 viscus two strong bundles of the anterior longitudinal iibres run one on each side 

 of the middle line in front of the anterior wall of the jjrostate and l)eneath the 

 pubo-i>rostatic ligament, to bccunif attachid to the liack of the pubic bones on 

 eacli side of the synii)hysis (vesico-pubic muscle). The lower fibres of the 

 iiiiildle layer form a kind of annular sphincter near the urethral orifice (sphincter 

 vesicae internus), the fibres of which are continuous with the upper sphincteric 

 fil)res of the j)rostate, and at the trigone are reinforced by the exi)ansion of the 

 longitudinal ureteric filjres named on page 1016. The inner layer ajjpears as a set 

 of well-defined bands running in a longitudinal direction and communicating with 

 eacli other by means of oblique fasciculi. These bands, when hypertro))hied, 

 appear as distinct ridges l)eneath the nuicous membrane, and their interspaces 

 may be seen as depressions wiiich occasionally develop into diverticula. At 

 the trigone, the inner layer is strengthened by the radiation of the ureteric 

 filjres. 



The rather coarse meshwork formed by the decussating muscular Ijundles is apt 



Fig. 618.— The Posterior Wall of the Bladder. (After Hcnle.) 



URETER PIERCING VESICAL 

 WALL 



PLICA URETERICA 

 VESICAL APERTURE OF 

 URETER 



MUSCULARIS 



UVULA OF LiEUTA'j: 



VERUMONTANUM 



OPENING OF EJACULATORY DUCT 



SINUS POCULARIS 



PROSTATIC SINUS 



to ])re>ent weak points througli whicli the mucous membrane may protrude as 

 diverticular sacculations, sometimes of considerable size and capable of lodging 

 calculous concretions. On the other hand, Avhen the muscular tissue becomes 

 hypertrophied from excessive use, it often forms strong ridge-like ])rojections which 

 may give rise to deceptive impressions during exploration of the cavity with the 

 sound. 



The submucous coat consists of a highly clastic connective tissue devoid of 

 muscular fibres. 



The mucous membrane is smooth, soft, and rose-coloured during life. In the 

 empty bladder it is tlirowninto irregular folds, which become efFaeed l\v distension. 

 It is modified posteriorly over a triangidar area called the Trigone of Lieutaud 

 (fig. 61.'*'), the three angles of which lie at the internal meatus and the two mvteric 

 orifices, and are at a distance from each other of three-(iuarters of an inch to an 

 inch (18 to 25 mm. ). This region, which lies opposite to the ' second portion ' of the 

 rectum, is free from the ])lication that a])p»'ars in tlie rest of the mucous membrane 

 during contraction of the cavity, nod is bounded V)y a transverse elevati">n l>etwcen 

 the in-eters, called the plica ureterica, and jiresents a longitudinal mesial ridge, 

 the uvula of Lieutaud. near the lU'cthral orifice. It is smaller and less distinct 

 in the female. The infmidl urinary meatus usually lies ;it tlie niosf dependent part 



