INTERNAL ILIAC. 431 



to the bladder, it ascends along the side of that viscus to its summit, to which 

 it gives branches ; it then passes upwards along the back part of the anterior wall 

 of the abdomen to the umbilicus, converging towards its fellow of the opposite 

 side. Having passed through the umbilical opening, the two arteries twine round 

 the umbilical vein, forming with it the umbilical cord ; and, ultimately, ramify in 

 the placenta. That portion of the vessel placed within the abdomen is called the 

 hypogastric artery ; and that external to that cavity, the umbilical artery. 



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

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

 and ultimately dwindles to a solid fibrous cord; the portion of the same vessel 

 extending from the summit of the bladder to within an inch and a half of its origin, 

 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 its 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. 



Tho 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 vs/ies between 

 the upper margin of the sacrum, and the upper border of the sacro-sciatic foramen. 



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

 constantly to exceed the other. 



Surgical 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. This vessel may be secured 

 by making an incision through the abdominal parietes in the iliac region, in a direction and to an 

 extent similar to that for securing the common iliac ; the transversalis fascia having been cau- 

 tiously divided, and the peritoneum pushed inwards from the iliac fossa towards the pelvis, the 

 finger may feel the pulsation of the external iliac at the bottom of the wound ; and, by tracing 

 this vessel upwards, the internal iliac is arrived at, opposite the sacro-iliac articulation. It should 

 be remembered that the vein lies behind, and on the right side, a little external to the artery, and 

 in close contact with it ; the ureter and peritoneum, which lie in front, must also be avoided. 

 The degree of facility in applying a ligature to this vessel will mainly depend upon its length. 

 It has been seen that, in the great majority of. the cases examined, the artery was short, varying 

 from an inch to an inch and a half; in these cases, the artery is deeply seated in the pelvis ; when, 

 on the contrary, the vessel is longer, it is found partly above that cavity. If the artery is very 

 short, which occasionally happens, it would be preferable to apply a ligature to the common iliac, 

 or upon the external and internal iliacs at their origin. This operation has been performed in 

 seven cases, four of which recovered, and three died. 



Collateral Circulation. In Mr. Owen's dissection of a case in which the internal iliac artery 

 hid been tied by Stevens ten years before death, for aneurism of the sciatic artery, the internal 

 iliac was found impervious for about an inch above the point where the ligature had been applied; 

 but the obliteration did not extend to the origin of the external iliac, as the ilio-lumbar artery 

 arose just above this point. Below the point of obliteration, the artery resumed its natural 

 diameter, and continued so for half an inch ; the obturator, lateral sacral, and gluteal, arising in 

 succession from the latter portion. The obturator artery was entirely obliterated. The lateral 

 sacral artery was as large as a crow's quill, and had a very free anastomosis with the artery of 

 the opposite side, and with the middle sacral artery. The sciatic artery was entirely obliterated 

 as far as its point of connection with the aneurismal tumor ; but, on the distal side of the sac, it 

 was continued down along the back of the thigh nearly as large in size as the femoral, being 

 pervious about an inch below the sac by receiving an anastomosing vessel from the superior 

 profunda. 1 In addition to the above, the circulation in the parts supplied by the internal iliac 

 would be 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 ; by the anastomoses of the circumflex, and 

 perforating branches of the femoral, with the sciatic ; of the gluteal with the posterior branches 

 of the sacral arteries ; of the ilio-lumbar with the last lumbar ; of the lateral sacral with the 

 middle sacral ; and by the anastomoses of the circumflex iliac with the ilio-lumbar and gluteal. 



1 Medico- Chirurgical Transactions, vol. xvL 



