THE INTERNAL ILIAC ARTERY 673 



the two arteries, now termed umbilical, enter the umbilical cord, where they are 

 roiled around the umbilical vein and ultimately ramify in the placenta. 



At birth, when the placental circulation ceases, the portion of the hypogastric 

 artery which extends from the summit of the bladder to the umbilicus, contracts, 

 and ultimately dwindles to a solid fibrous cord, the impervious hypogastric artery 

 (lig. umbilicale laterale), but the lower portion, extending from its origin (in what 

 is now the internal iliac artery) for about an inch and a half to the wall of the 

 bladder, and thence to the summit of that organ, is not totally impervious, though 

 it becomes considerably reduced in size, and serves to convey blood to the bladder 

 under the name of the superior vesical artery. 



Peculiarities as Regards Length. In two-thirds of a large number of cases the length of 

 the internal iliac varied between an inch and an inch and a half; in the remaining third it was 

 more frequently longer than shorter, the maximum length being three inches, the minimum 

 half an inch. 



The lengths of the common and internal iliac arteries bear an inverse proportion to each 

 other, the internal iliac artery being long when the common iliac is short, and vice versa. 



As Regards its Place of Division. The place of division of the internal iliac varies between 

 the upper margin of the sacrum and the upper border of the sacrosciatic foramen. 



The arteries of the two sides in a series of cases often differed in length, but neither seemed 

 constantly to exceed the other. 



Applied Anatomy. The application of a ligature to the internal iliac artery may be required 

 in cases of aneurism or hemorrhage affecting one of its branches. The best method of tying the 

 internal iliac artery is by an abdominal section in the median line and reaching the vessel through 

 the peritoneal cavity. This plan has been advocated by Dennis, of New York, on the following 

 grounds: (1) It in no way increases the danger of the operation; (2) it prevents a series of acci- 

 dents which have occurred during ligature of the artery by the older methods; (3) it enables the 

 surgeon to ascertain the exact extent of disease in the main arterial trunk, and select his spot for 

 the application of the ligature; and (4) it occupies much less time. 



Collateral Circulation. The circulation after ligature of the internal iliac artery 1 is carried 

 on by the anastomoses of the uterine and ovarian arteries; of the opposite vesical arteries; of 

 the hemorrhoidal branches of the internal iliac with those from the inferior mesenTeric: of the 

 obturator artery, by means of its pubic branch, with the vessel of the opposite side and with the 

 epigastric and internal circumflex; of the circumflex and perforating branches of the profunda 

 femoris with the sciatic; of the gluteal with the posterior branches of the sacral arteries; of the 

 iliolurnbar with the last lumbar; of the lateral sacral with the middle sacral; and of the cir- 

 cumflex iliac with the iliolumbar and gluteal. 



Branches (Fig. 473). The branches of the internal iliac are: 



From the Anterior Trunk. From the Posterior Trunk. 



Superior vesical. Iliolumbar. 



Middle vesical. Lateral sacral. 



Inferior vesical. Gluteal. 



Middle hemorrhoidal. 

 Obturator. 

 Internal pudic. 

 Sciatic. 

 Uterine 

 Vaginal 



The superior vesical (a. vesicalis superior) (Fig. 473) is the terminal part of 

 the previous portion of the fetal hypogastric artery. It extends to the side of 

 the bladder, distributing numerous branches to the apex and body of the organ. 

 From one of these a slender vessel is derived which accompanies the vas deferens 

 in its course to the testis, where it anastomoses with the spermatic artery. This is 

 the artery of the vas deferens. Other branches supply the ureter. 



1 For a description of a case in which Owen made a dissection ten years after ligature of the internal iliac 

 artery, see Medico-Chirurgical Transactions, vol. xvi. 



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