610 THE BLOOD-VASCULAR SYSTEM 



1^1 the prostatic plexus of veins, but outside the capsule of the prostate, and with the 



inferior haemorrhoidal branches of the internal pudic. At times one of these 

 prostatic branches is of large size, and supplies certain of the parts normally 

 supplied by the int. pudendal. It is then known as the accessory pudendal and 

 most commonl}' terminates as the dorsal artery of the penis. 



The inferior vesical usually gives off the deferential, or artery of the ductus deferens [a. 

 deferentiaUs]. This vessel, which may come off from the superior vesical, divides, on the ductus 

 deferens, into an ascending and a descending branch. The ascending branch follows the ductus 

 through the inguinal canal to the testis, where it anastomoses with the internal spermatic artery. 

 The descending branch passes downward to the dilated portion of the ductus and vesiculae 

 seminales. 



3. THE MIDDLE HAEMORRHOIDAL ARTERY 



The middle haemorrhoidal artery [a. hsemorrhoidals media], variable in origin, 

 perhaps most commonly arises from the anterior division of the hypogastric 

 along with the inferior vesical. It runs medially to the side of the middle portion 

 of the rectum, dividing into branches which anastomose above with the superior 

 haemorrhoidal derived from the inferior mesenteric, and below with the inferior 

 hsemorrhoidal derived from branches of the internal pudendal. Its corre- 

 sponding vein terminates in the inferior mesenteric vein. In the female it also 

 sends branches to the vagina. 



4. THE UTERINE ARTERY 



The uterine artery [a. uterina], arises from the anterior division of the hypo- 

 gastric close to or in conjunction with the middle hsemorrhoidal or inferior vesical. 

 It runs downward and medially through the pelvic connective tissue, crossing the 

 ureter about 12 mm. (| in.) from the cervix uteri. It then turns upward and 

 ascends in the parametrium between the layers of the broad ligament at the 

 side of the uterus in a coiled and tortuous manner, and, after giving off a number of 

 tortuous branches which ramify horizontally over the front and back of the uterus, 

 supplying its substance, anastomoses with the uterine branch of the ovarian 

 artery. 



In addition to the branches to the uterus the branches of the uterine artery are: — (1) 

 Cervical. — This branch comes off from the uterine as the latter artery crosses the ureter to turn 

 upward on to the uterus. It is directed medially, and divides into three or four branches which 

 pass on to the cervix at right angles to it; one branch anastomosing with its fellow of the opposite 

 side in front and behhid the neck, forming the so-called coronary artery of the cervix. (2) 

 Tubal [ramus tubarius]. — This courses along the lower surface of the tuba uterina (Fallopian 

 tube) as far as its fimbriated extremity, and may also send a branch to the ligamentum teres. 

 (3) Ovarian [ramus ovarii]. — This runs along the attached border of the ovary, sending branches 

 to that structure, and terminates by anastomosing widely with the ovarian artery. Usually 

 the vaginal artery also ari.ses from the uterine. (4) The vaginal artery [a. vaginalis] corresponds 

 to the inferior vesical arterj^ of the male, and may arise directly from the hypogastric artery, 

 close to the origin of the uterine, or from the superior vesical. It passes medially, behind the 

 ureter, to the upper part of the vagina, and sends muiierous branches to that structure and also 

 some to the posterior part of tlie fundus of the l)ladder. 



The branches to the vagina tend to anastomose with one another and with the cervical 

 branch of the uterine, to form a more or less perfect vertical stem in the median line of the vagina, 

 both back and front. This stem is sometimes termed the azygos artery of the vagina. Branches 

 also pass to the vagina from the middle huMuorrhoidal artery. 



5. THE INTERNAL PUDENDAL ARTERY 



The internal pudendal fpudic) artery [a. pudenda interna] (figs. 492, 493, 494) 

 is one of tin; tcriiiiual hranches of the anterior division of the hypogastric artery 

 (the inferior gluteal being the other). It arises opposite the piriformis muscle and 

 accompani(;s tin; inferior gluteal downward to the lower l)order of the great 

 sciatic foramen. It leaves the pelvis between the piriformis and coccygeus and 

 winds over the ischial spine to enter th(! ischio-rectal fossa through the small 

 sciatic foram(!n. Huuiiiiig forward in the ischio-rectal fossa medial to tiie lower 

 part of the obturator iiiterniis it ends by dividing into the perineal artery and the 

 artery of the penis (or clitoris). 



