VESICAL ARTERIES. ISCHIATIC ARTERY. 343 



Relations. This artery rests externally upon the sacral plexus and 

 upon the origin of the pyrifonnis muscle ; posteriorly it is in relation 

 with the internal iliac vein, and anteriorly with the ureter. 



Branches. The branches of the anterior trunk are the 



Umbilical, Ischiatic, 



Middle vesical, Internal pudic. 



Middle haemorrhoidal, 



And in the female the 

 Uterine, Vaginal. 



And of the posterior trunk, the 



Ilio-lumbar, Lateral sacral, 



Obturator, Gluteal. 



The umbilical artery is the commencement of the fibrous cord into 

 which the umbilical artery of the foetus is converted after birth. In 

 after life, the cord remains pervious for a short distance and constitutes 

 the umbilical artery of the adult, from which the superior vesical artery 

 is given off to the fundus and anterior aspect of the bladder. The 

 cord may be traced forwards by the side of the fundus of the bladder 

 to near its apex, whence it ascends by the side of the linea alba and 

 urachus to the umbilicus. 



The Middle vesical artery is generally a branch of the umbilical, 

 and sometimes of the internal iliac. It is somewhat larger than the 

 superior vesical, and is distributed to the posterior part of the body of 

 the bladder, the vesiculae seminales, and prostate gland. 



The Middle Juemorrhoidal artery is as frequently derived from the 

 ischiatic or internal pudic as from the internal iliac. It is of variable 

 size, and is distributed to the rectum, base of the bladder, vesiculas 

 seminales, and prostate gland ; and inosculates with the superior and 

 external haemorrhoidal arteries. 



The ISCHIATIC ARTERY is the larger of the two terminal branches 

 of the anterior division of the internal iliac. It passes downwards 

 between the posterior border of the levator ani, and the pyriformis, 

 resting upon the sacral plexus of nerves and lying behind the internal 

 pudic artery, to the lower border of the great ischiatic notch, where it 

 escapes from the pelvis below the pyriformis muscle. It then de- 

 scends in the space between the trochanter major and the tuberosity 

 of the ischium in company with the ischiatic nerves, and divides into 

 branches. 



Its branches within the pelvis are hcemorrkoidal which supply the 

 rectum conjointly with the middle hsemorrhoidal and sometimes take 

 the place of that artery, and the inferior vesical which is distributed 

 to the base and neck of the bladder, the vesiculae seminales, and 



