SMALLER BRANCHES OF THE INTERNAL ILIAC. 295 



to the lower part of the side of the bladder, and from thence to 

 the umbilicus, under the denomination of the Umbilical Ar- 

 tery. From the convex side of this curve the different branches 

 of the internal iliac go off. In the foetal state they are very 

 small, in proportion to the umbilical artery ; but as the artery 

 becomes ligamentous, these branches increase in size. 



In the adult, the arrangement of these vessels is very differ- 

 ent. The Internal Iliac generally divides into two great 

 branches ; the Gluteal, which passes through the sacro-sciatic 

 notch, and ramifies on the exterior and upper part of the os 

 ilium : and the Ischiatic, which passes downwards on the out- 

 side of the tuberosity of the ischium. 



The former of these large ramifications passes out of the pel- 

 vis above the pyriform muscle, and the latter of them below it. 

 Several smaller arteries arise from these branches near their 

 origin, or from the main trunk of the internal iliac, which are 

 distributed to the different parts of the pelvis ; and one im- 

 portant branch of the ischiatic, called the Pudic, proceeds 

 downwards on the inside of the tuberosity of the ischium. 



The first of the smaller branches which the external iliac 

 commonly sends off, is called the 



Ileo Lumbalis. 



The ilio-lumbar artery sometimes arises from the gluteal 

 artery, and sometimes from the main trunk of the internal iliac. 

 It passes outwards under the psoas muscle, and suddenly 

 divides into two branches. One of them proceeds upwards, 

 and is distributed in the lumbar region, while the other ramifies 

 on the iliacus internus muscle, and is spent on the contiguous 

 parts. 



There are, also, two or three small arteries called 



Arteria Sacra Laterales, 



Which sometimes arise singly, and sometimes in common, 

 from the great trunk. They also occasionally originate from 

 the gluteal artery. These vessels enter the anterior foramina 

 of the os sacrum, to be distributed on the cauda equina and 



