MUSCULAR COAT OF THE BLADDER. 129 



The peritoneum is reflected at the anterior part of the brim 

 of the pelvis from the abdominal muscles, which it lines, to the 

 upper part of the bladder, which is generally contiguous to ftie 

 brim of the pelvis. It continues over to the posterior skie of 

 the bladder, and passes down upon it some distance towards the 

 lower part ; but before it has arrived at the bottom, it is reflected 

 towards the sacrum. 



In males it extends from the bladder to the rectum, and in 

 females, to the vagina and uterus ; so that [there is a consider- 

 able portion of the lower part of the bladder which is not 

 invested by the peritoneum. It also follows, that when the 

 bladder is extended into the abdomen, and rises above the brim 

 of the pelvis, that part of it which presents anteriorly, and is in 

 contact with the abdominal muscles, is without a covering of 

 peritoneum ; being below it. 



Fig. 155.* It is usual for anatomists and 



pathologists to divide the bladder 

 when moderately distended into four 

 rpginns:, for the purpose of descrip- 

 tion, viz. the middle part or body, the 

 top or upper fundus, the inferior part 

 or lower fundus, and the neck, at 

 which the urethra commences. 

 In the foetus and young child, the 

 neck of the bladder is the most de- 

 pending portion. In the adult, the 

 bottom of the bladder is depressed 

 and expanded, so as to form a pouch 

 below the level of the neck, which is 



technically known as the bets fond. In this part the urine first 

 begins to accumulate when the organ has been emptied, and 

 calculi usually lodge. 



* The posterior aspect of the male bladder ; the serous covering is remov- 

 ed in order to show the muscular coat. 1. The body of the bladder. 2. Its 

 upper fundus. 3. Its lower fundus or base. 4. The urachus. 5, 5. The ure- 

 ters. 6, 6. The vasa deferentia. 7, 7. The vesiculae seminales. 8. The 

 triangular area, corresponding with the trigonum vesicae through which the 

 bladder would be pierced, in puncturing the bladder through the rectum. The 

 dotted line forming the base of this triangular area, marks the extent to which the 

 recto-vesical fold of the peritoneum, descends upon the lower fundus of the bladder. 



