516 DISSECTION OF THE PELVIS. 



Sometimes the obturator may take origin from the external iliac artery. 



The sciatic artery (fig. 176, n) is the next largest branch to the gluteal, 

 and is continued over the pyriformis muscle nnd the sacral plexus to the 

 lower part of the sacro-sciatic notch, where it issues between the pyriformis 

 and the coccygeus. External to the pelvis it divides into branches beneath 

 the glutens maximus, and is distributed to the buttock : in the pelvis it 

 supplies the pyriformis and coccygeus muscles. 



The pudic artery (tig. 17G, 0) supplies the perineum and the genital 

 organs, and has nearly the same connections in the pelvis as the sciatic, 

 from which it often springs. It accompanies the sciatic, though external 

 to it, and leaves the pelvis between the pyriformis and coccygeus. At the 

 back of the pelvis it winds over the ischial spine of the hip bone, and 

 enters the perinaeal space (p. 390). The artery gives some unimportant 

 offsets in the pelvis, arid frequently the middle hremorrhoidal branch arises 

 from it. 



Accessory pudic (Quain). The pudic artery is sometimes smaller than 

 usual, and fails to supply some of its ordinary perinatal branches, especially 

 the terminal for the penis. In those cases the deficient branches are de- 

 rived from an accessory artery, which takes origin from the internal iliac 

 (mostly from the trunk of the pudic), and courses forwards on the side of 

 the bladder and the prostate gland, to perforate the triangular perimeal 

 ligament. It furnishes branches to the penis to supply the place of those 

 that are wanting. 



c. The branches of the internal iliac artery which are peculiar to the 

 female are two, the uterine and vaginal. 



The uterine artery (fig. 17.0, d~) passes inwards between the layers of 

 the broad ligament to the neck of the uterus, where the vessel changes its 

 direction, and ascends to the fundus. Numerous branches enter the sub- 

 stance of the uterus, and, ramifying in it, are remarkable for their tortuous 

 condition. 



At the neck of the. uterus some small twigs are supplied to the vagina 

 and the bladder ; and opposite the ovary a branch bends outwards to anas- 

 tomose with the ovarian artery (spermatic) of the aorta. 



The vaginal artery (fig. 1 75, e) seldom arises separately from the inter- 

 nal iliac. Combined with the preceding, or with the branch to the rectum, 

 this artery extends along the vagina, and ramifies in its wall as low as the 

 outer orifice. 



Other arteries in the pelvis. The remaining arteries in the pelvis, which 

 are not derived from the internal iliac, are the ovarian, superior luemor- 

 rhoidal, and middle sacral. 



The ovarian artery (p. 490), after passing the brim of the pelvis, be- 

 comes tortuous, and enters the broad ligament to be distributed to the 

 ovary : it supplies an offset to the Fallopian tube, and another to the round 

 ligament; and a large branch anastomoses internally with the, uterine 

 artery. 



The superior hcemorrhoidal artery, the continuation behind the rectum 

 of the inferior nu-senteric. (p. 441), divides into two branches near the 

 middle of the sacrum. From the- point of division the branches are con- 

 tinued along the rectum, one on each side, and each ends finally in about 

 three branches, which pierce the layer of the gut three inches from the 

 anus; they terminate opposite the inner sphincter in anastomotic loops 

 beneath the mucous membrane, and anastomose with the middle and in- 

 ferior ha^morrhoidal arteries. 



