Chap, xviii.] THE BLADDER. 397 



or by violence applied through the rectum or vagina. 

 A case, for example, is reported (Holmes' " System of 

 Surgery ") of a man who fell upon a pointed stake 

 fixed in the earth. The stake passed through the 

 anus, pierced the rectum, and entered the bladder near 

 the prostate. The patient recovered, the wound 

 having been made in the triangular area on the fundus 

 of the bladder alluded to above, and therefore outside 

 the peritoneum. The viscus may be ruptured by an 

 accumulation of urine, as seen in cases of congenital 

 closure of the urethra in some infants. In the museum 

 of the Royal College of Surgeons is a preparation of 

 " the bladder of a woman which burst near the entrance 

 of the ureter in consequence of neglected retention of 

 urine." In neglected cases of stricture in the male 

 the urethra gives way rather than the bladder, and 

 an extravasation 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 contraction of its wall. 



The mucous membrane of the bladder is very 

 lax, to allow of its accommodating itself to the vary- 

 ing 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 micturi- 

 tion 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 

 structure. Since the oritice of the urethra forms the 

 lowest part of the bladder in the erect posture, it 

 follows that calculi gravitate towards the trigono, and 



