F | THE BLADDER. 1091 
from the openings of the ureters, but on a lower level. The size and shape of the 
bladder, and also to a great extent its relations, vary with the amount of disten- 
sion, or contraction, of the organ. When the bladder is empty, or only slightly 
distended, it lies within the pelvic cavity; as it becomes filled with urine it rises 
above the pubis, and, crossing the pelvic brim, enters the abdominal eavi ty. These 
First sacral vertebra 
Recto-vesical 
Peritoneal \ ¥ = + ee Zz ‘ar a peritoneal reflexion 
reflexion 1 x eae = r <S e Ua OT) g— Cavity of bladder 
Vas deferens 
Rectum 
Symphysis pubis 
Prostate 
Compressor urethree 
\isaeettes sphincter ani 
Corpus 
cavernosum 
y_ Internal sphincter ani 
Bulb of urethra —y Anal canal 
Bulbo-cavernosus i 
muscle” External sphincter ani 
Fic. 737. 
MESIAL SECTION THROUGH THE MALE PELVIS. 
The bladder contains but a smali amount of fluid. The separation between the bladder and prostate is shown 
somewhat diagrammatically. Drawn from a preparation in the Anatomical Department, Trinity College, 
Dublin. 
changes aftect chiefly the upper part of the bladder, which becomes altered in 
Shape and size, and acquires new connexions and relations; the lower portion 
varies but slightly with the amount of distension of the organ (see Figs. 737 and 738). 
The position occupied by the bladder depends, to a certain extent, on the condi- 
tion of the rectum, for when the lower part of the rectum is distended, the bladder 
as a whole is thrust somewhat upwards and forwards. The upper part of the 
bladder is covered by peritoneum, which is reflected on to it from the anterior 
abdominal wall in front, from the sides of the pelvis laterally, and, in the male, 
from the rectum behind. In the female the peritoneum passes from the anterior 
surface of the uterus on to the bladder. The peritoneum dips down posteriorly for 
a certain distance between the bladder and rectum in the male, forming the 
recto-vesical pouch of peritoneum; in the female a somewhat similar pouch 
is present between the bladder and the uterus (Fig. 744). The under part 
of the bladder which hes below the peritoneum is for the most part directed 
towards the pelvic floor. In the middle line it is supported by the symphysis 
pubis and the retro-pubic pad of fat; further back in the male it rests upon the 
prostate and on the lower part of the rectwm, from which latter it is separated by 
ry 
