398 



DISSECTION OF THE PELVIS. 



supply 

 spinal 

 branches. 



Gluteal 

 artery : 



small 

 offsets. 



Branches 

 of anterior 

 part. 



Upper 

 vesical. 



Lower 

 vesical 



or vaginal. 



Middle 

 hsemor- 

 rhoidal. 



Hypogastric 

 trunk. 



Obturator 

 artery 

 courses 

 across 

 pelvis : 



offsets in 

 pelvis ; 

 iliac branch, 



bic 



pUDIC 



branch. 



superior and inferior : they correspond in situation with the 

 lumbar arteries, and form a chain of anastomoses by the side of 

 the apertures in the sacrum. These arteries supply the pyriformis 

 and coccygeus muscles, and anastomose with each other, as well as 

 with the middle sacral. A spinal branch enters each aperture in the 

 sacrum. 



The gluteal artery (tig. 148, m) is the continuation of the posterior 

 division of the internal iliac, and is destined for the gluteal muscles 

 on the outer surface of the hip-bone. It is a short, thick trunk, 

 which leaves the pelvis through the great sacro-sciatic foramen 

 above the pyriformis muscle, with its accompanying vein and the 

 superior gluteal nerve, passing between the lumbo-sacral cord and 

 the anterior division of the first sacral nerve, or sometimes between 

 the anterior divisions of the first and second sacral nerves, as in 

 fig. 148. In the pelvis the artery gives small branches to the con- 

 tiguous muscles, viz., iliacus, pyriformis, and obturator, and a twig 

 to the hip-bone. 



B. The BRANCHES of the anterior division of the internal iliac 

 artery are the following : 



The superior vesical artery is the imperfectly obliterated portion 

 of the fretal hypogastric artery. It divides into three or four 

 branches, which ramify over the apex and body of the bladder : the 

 lowest of these is sometimes called the middle vesical branch. 



The inferior vesical artery often arises in common with the branch 

 to the rectum. It is distributed to the base of the bladder, the 

 vesiculse seminales, and the prostate. A small offset from this 

 artery, or from the upper vesical, is furnished to the vas deferens, 

 and is known as the artery of the vas deferens. 



The vaginal artery (fig. 147, e) of the female takes the place of 

 the inferior vesical of the male. It descends 011 the vagina, and 

 ramifies in its wall as low as the outer orifice ; while, superiorly, it 

 communicates with the lower branches of the uterine artery. This 

 branch is often given off by the uterine artery. 



The middle hcemorrhoidal artery (fig. 148, I) commonly arises from 

 the inferior vesical (or vaginal), or from the pudic trunk. It is 

 spent on the anterior and lower part of the rectum, and anastomoses 

 with the other haemorrhoidal arteries. 



The preceding arteries sometimes arise in common with the 

 superior vesical, and the trunk of origin is termed the hypogastric 

 trunk. 



The obturator artery (fig. 148, k) is directed forwards below the 

 brim of the pelvis to the aperture at the top of the thyroid foramen ; 

 passing through that opening it ends in two branches, which 

 ramify on the membrane closing the thyroid foramen, beneath the 

 obturator externus muscle. In. the pelvis the artery has its com- 

 panion nerve above, and vein below it ; and it there gives rise to : 



An iliac branch which enters the iliac fossa to supply the bone 

 and the iliacus muscle, and anastomoses with the ilio-lumbar artery. 



A pubic branch (fig. 107, /, p. 294) ascends on the posterior 

 aspect of the pubis, and communicates with the corresponding 



