1252 



UROGENITAL SYSTEM 



directly upward into the abdominal cavity and has resting upon it coils of the 

 small intestines and sometimes a portion of the sigmoid colon behind these. 



Variation in position. — In the normal condition the bladder of the adult lies below the upper 

 border of the symphysis pubis, but if fully distended it may rise above this level, carrying 

 with it the reflexion of peritoneum from its upper surface to the anterior abdominal wall. 

 The anterior surface of the bladder is thus brought into relation with the anterior abdominal 

 wall, being separated from it only by the enlarged prevesical space, and it is thus possible to 

 enter the bladder above the symphysis pubis without penetrating the peritoneum. 



In the infant, owing to the smaller extent of the pelvic cavity, the bladder lies at a some- 

 what higher level than in the adult and rises into the abdominal cavity. Indeed the entire 

 bladder is above the horizontal level of the pubic crests, the urethral orifice being behind the 

 upper margin of the symphysis pubis. As the child learns to walk, however, this position 

 gradually alters and usually by the age of six years the adult relations have been acquired. 



The fixation of the bladder. — The reflections of the peritoneum from the 

 superior surface of the bladder to the anterior abdominal wall and from the sides 

 and back to the corresponding walls of the pelvis are sometimes described as the 

 superior, lateral and posterior false ligaments. Furthermore there extends from 

 the apex of the bladder to the umbilicus a fibrous cord, the urachus, the remains 

 of the embryonic allantois; this is described as the middle umbilical ligament of 

 the bladder (fig. 1014), and lateral lunhilical ligaments are formed by the obliter- 

 ated hypogastric arteries which carried the foetal blood to the placenta and in the 



Fig. 1015. — The Posterior Wall of the Bladder. (After Henle.) 



Ductus deferens 



Ureter piercing 

 vesical wall 



Plica ureterica 



Vesical aperture 



of ureter 



Muscularis 



Mucosa 

 Uvula — 



Colliculus seminalis 



Opening of ejaculatory duct 



Prostatic utriculus 



Prostatic sinus 



adult are represented by fibrous cords passing over the sides of the bladder and 

 ascending to the umbilicus. 



In addition to these structures certain thickenings of the endopelvic fascia, 

 where it comes into relation with the base of the bladder and prostate gland, 

 constitute what are termed the true ligaments. Two such thickenings extend 

 from the anterior surface of the capsule of the prostate gland, or from the lower 

 part of the anterior surface of the bladder in the female, to the pubic bones and 

 constitute what are known as the middle pubo-prostatic (pubo-vesical) ligaments, 

 with which muscle fibres [m. pul)ovesicalis] are usually associated. Similarly, 

 thickenings of the fascia extending from the sides of the prostate gland or from the 

 sides of the base of the bladder to the lateral walls of the pelvis form the lateral 

 true ligaments. 



Muscle fibres [m. rcctovosicalis] also occur in the subperitoneal tissue contained within 

 the peritoneal folds (posterior false ligaments) extending from the back of the bladder to the 

 posterior wall of the pelvis and bounding the recto-vesical pouch of jicritoneum in the male. 

 They correspond to the mm. rectoulerini of the female. 



The internal surface. — The mucous membrane hning the internal surface of 

 the bladder is soft and rose-coloured during life, and in the empty bladder is 

 thrown into irregular folds which become effaced by distention. It is modified 

 over a triangular ar(!a at the base of the l)lad(ler, termed the trigone [trigonum 

 vesica3 (Lieutaudi)J (fig. •1015) whose three angles correspond with the orifices 

 of the urethra ancl of tin; two ureters, and are separated from one another by a 



