Chap. xviii.] THE BLADDER. 357 



neglected cases of stricture in the male the urethra 

 gives way rather than the bladder, and an extravasa- 

 tion of urine into the perineum follows. A small 

 puncture of the bladder, as, for example, that made by 

 a fine trochar, is at once closed by the muscular con- 

 traction of its wall. 



The mucous membrane of the bladder is very 

 lax, to allow of its accommodating itself to the varying 

 changes in the size of the viscus. Over the trigone, 

 however, it is closely adherent, and were it not so the 

 loose mucous membrane would be constantly so 

 prolapsed into the urethral orifice during micturition 

 as to block up the neck of the bladder. The trigone 

 is bounded by three orifices, for the urethra and 

 the two ureters, and forms an equilateral triangle, 

 measuring about one and a half inches on all sides. 

 It is here that the effects of cystitis are most evident, 

 and the unyielding character of the mucous membrane 

 over the trigone serves in part to explain the severe 

 symptoms that follow acute inflammation of that struc- 

 ture. Since the orifice of the urethra forms the 

 lowest part of the bladder in the erect posture, it 

 follows that calculi gravitate towards the trigone, and 

 are very apt to irritate that part of the interior. The 

 same remark applies to foreign bodies in the viscus. 

 The mucous membrane about the trigone and neck is 

 very sensitive, whereas the interior of the remainder 

 of the bladder appears to be singularly defective in 

 common sensation. This can be well noted in using 

 sounds and catheters. 



In the muscular coat of the viscus the fibres 

 are collected into bundles which interlace in all 

 directions. When the bladder becomes hypertrophied 

 these bundles are rendered very distinct, and produce 

 the appearance known as " fasciculated bladder." 

 This simply means that the muscle of the bladder, 

 having been unduly exercised to overcome some 



