BRANCHES OF THE IXTEPXAL ILIAC. 623 



sommunicating with offsets from the deep epigastric artery and with the corre- 

 sponding vessel of the opposite side. This branch is placed on the inner side of 

 the femoral ring. External to the pelvis, the obturator artery divides into an 

 iial and an external branch, which are deeply situated beneath the Obturator 

 externus muscle. 



The internal branch curves downward along the inner margin of the obturator 

 foramen, distributing branches to the Obturator externus muscle, Pectineus. 

 Adductors, and Gracilis. and anastomoses with the external branch and with the 

 internal circumflex artery. 



The external branch curves round the outer margin of the foramen to the 



space between the Gemellus inferior and Quadratus femoris. where it anastomoses 



with the sciatic artery. It supplies the Obturator muscles, anastomoses, as it 



a backward, with the internal branch and with the internal circumflex, and 





FIG. 373. Variations in origin and course of obturator artery. 



sends a branch to the hip-joint through the cotyloid notch, which ramifies on the 

 round ligament as far as the head of the femur. 



Peculiarities. In two out of every three cases the obturator arises from the internal iliac . 

 in one case in three and a half from the epigastric ; and in about two and a half in seventy-two 

 iiy two routs from both vessels. It arises in one and two-tenths per cent, from the exter- 

 nal iliac artery. The origin of the obturator from the epigastric is not commonly found on both 

 sides of the same body. 



When the obturator artery arises at the front of the pelvis from the epigastric, it descends 

 almost vertically to the upper part of the obturator foramen. The artery in this course usually 

 lies in contact with the external iliac vein and on the outer side of the femoral ring (Fig. 373, A) ; 

 in such cases it would not be endangered in the operation for femoral hernia. Occasionally. 

 however.it curves inward along the free margin of Gimbernat's ligament I Fig. 373. B'. and 

 under such circumstances would almost completely encircle the neck of a hernial sac (supposing 

 a hernia to exist in such a case), and would be in great danger of being wounded if an operation 

 was performed. 



The internal pudic is the smaller of the two terminal branches of the anterior 

 trunk of the internal iliac, and supplies the external organs of generation. 

 Though the course of the artery is the same in the two sexes, the vessel is much 

 smaller in the female than in the male, and the distribution of its branches 

 somewhat different. The description of its arrangement in the male will first be 

 given, and subsequently the differences which it presents in the female will be 

 mentioned. 



The Internal Pudic Artery in the Male passes downward and outward to the 

 lower border of the great sacro-sciatic foramen, and emerges from the pelvis 

 between the Pyriformis and Coccygeus muscles : it then crosses the spine of the 

 ischium and re-enters the pelvis through the lesser sacro-sciatic foramen. The 

 artery now crosses the Obturator internus muscle along the outer Avail of the ischio- 

 rectal fossa, being .situated about an inch and a half above the lower margin of the 

 ischial tuberosity. It is here contained in a sheath of the obturator fascia, and 

 gradually approaches the margin of the ramus of the ischium. along which it passes 

 forward and upward, pierce? the posterior layer of the deep perineal fascia, and 

 runs forward along the inner margin of the ramus of the os pubis ; finally, it 

 perforates the anterior layer of the deep perineal fascia and divides into its two 



