228 SURGICAL ANATOMY OF 



trocar enters in puncture per rectum. The trigone is 

 perfectly smooth, and free from rugse. 



Immediately behind the trigone, is the deepest part of 

 the bladder, the bos fond not very much marked in 

 children, but forming a considerable pouch in old per- 

 sons, in which the urine settles, causing considerable 

 irritation. It is in this pouch that calculi lodge gener- 

 ally. 



In the female the bladder is rather larger than in the 

 male. It has no has fond. The neck is lower, and it 

 and the posterior portion of the bladder lie on the 

 vagina. Fistulous openings occasionally occur between 

 the bladder and vagina, or rectum and vagina. 



Internal Iliac Artery. The artery of the region is the 

 internal iliac, which furnishes, with the exception of the 

 middle sacral, all the vascular supply of the walls, the 

 soft parts, and viscera. It is given off from the com- 

 mon iliac, between the sacro-iliac synchondrosis and the 

 sacro- vertebral angle. 



After birth the vessel consists of two trunks, an ante- 

 rior and a posterior a subdivision which takes place 

 opposite the great sacro-sciatic notch. The branches 

 given off from the anterior are those to the bladder and 

 prostate ; superior vesical (the pervious portion of the 

 foetal hypogastric artery), middle and inferior vesical, 

 the middle hsemorrhoidal to the rectum, the obturator, 

 the internal pudic and ischiatic, and the uterine and vag- 

 inal in the female. Those given off from the posterior 

 trunk are the gluteal, ilio-lumbar, and lateral sacral. 

 The gluteal, ischiatic, and internal pudic leave the pel- 

 vis by the great sacro-sciatic notch, passing between the 

 sacral plexus of nerves. 



Relations of the Internal Iliac Artery. The internal 



