TEE INTERNAL ILIAC ARTERIES. 625 



3. Slender ramifications for the pelvic portion of the urethral canal, Cowper's 

 glands, the anus, and the erector penis muscle. 



The terminal extremity of the vessel is insinuated beneath the accelerator 

 urinaB muscle, and immediately divides into a multitude of ramuscules which 

 enter the erectile tissue of the urethral bulb, where they comport themselves as in 

 all tissues of this kind. 



Varieties. — It is not rare to see this artery detach — before reaching Cowper's 

 gland — the cavernous artery., which then passes round the ischial arch along with 

 the nerve of the penis. Sometimes it only gives off the posterior dorsal artery of 

 the penis — a branch of the cavernous. 



Internal Pudic Artery in the Female. (Fig. 370, 4.) — This artery ter- 

 minates, towards the vagina, by rectal, vulvar, vaginal, and bulbar branches ; 

 the latter are for the bulb of the vagina. As in the male, it does not 

 give off more than one important branch on its course ; this — the vaginal artery 

 (Fig. 370, .5) — is analogous in every respect to the vesico-prostatic artery ; its 

 terminal divisions go not only to the middle portion of the vagina, but also to 

 the body of the uterus, where they anastomose largely with the branches of the 

 uterine artery, and even pass to the bladder and rectum. 



The internal pudic artery of the female, as in the male, is liable to numerous 

 variations. It may furnish the cavernous artery, or only the dorsal artery of the 

 clitoris. We have seen the vaginal artery come from the umbilical. 



3. Lateral Sacral or Subsacral Artery (Figs. 368, 12 ; 370, 6). 



Rising from the inner side of the internal iliac artery, at, or a little behind 

 the lumbo-sacral articulation, lying above the peritoneum, and beneath the 

 sacral foramina and the large nerves passing through them, this vessel is directed 

 backwards, and arrives near the posterior extremity of the sacrum, where it ends 

 in two branches : the ischiatic and lateral coccygeal arteries^ to which must be 

 added the middle coccygeal artery, usually given off by the vessel of the right 

 side. 



Collateral Branches. — The lateral sacral artery sends off on its course 

 several insignificant ramuscules destined for the neighbouring parts, and four 

 spinal branches which enter the spinal canal by the inferior sacral foramina, and 

 leave it again by the superior, after throwing off some divisions to the posterior 

 extremity of the spinal cord and the cauda equina nerves ; these branches ramify 

 in the muscles lying along the sacral spine. 



Terminal Branches. — 1. Ischiatic Artery.— It crosses the sacro-sciatic 

 ligament, to place itself under the superior extremity of the posterior portion 

 of the superficial gluteus, passes backwards and downwards, and divides into 

 several branches which descend into the substance of the semimembranosus and 

 semitendinosis muscles, to beneath the ischial tuberosity. These branches 

 anastomose, by their extremities, with the ascending branches from the femoro- 

 popliteal, as well as with the divisions of the obturator and deep femoral 

 arteries. 



2. Lateral Coccygeal Artery.— This vessel represents the continuation 

 of the lateral sacral artery, though not by its volume — which is much less than 

 that of the ischiatic artery — but in its direction. It proceeds from before to 

 behind, for the whole length of the coccyx, between the rudimentary vertebra of 

 that region and the compressor coccygis, gradually diminishing in volume, and 



