510 ARTERIES. 



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 length. In two-thirds of a large number of cases, the length of the 

 internal iliac varied between 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 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. The 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 

 cautiously 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, vary- 

 ing 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, as occasionally happens, it would be preferable to apply a ligature to the common 

 iliac, or upon the external and internal iliacs at their origin. 



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

 had 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 natuml 

 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 con- 

 tinued 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 profunda. 1 In ad- 

 dition 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 

 haemorrhoidal branches of the internal iiiac, with those from the inferior mesenteric ; of the ob- 

 turator 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. 



BRANCHES OF THE INTERNAL ILIAC. 



From the Anterior Trunk. From the Posterior Trunk. 



Superior vesical. Gluteal. 



Middle vesical. Ilio-lumbar. 



Inferior vesical. Lateral sacral. 



Middle ha3morrhoidal. 



Obturator. 



Internal pudic. 



Sciatic. 

 Uterine. 

 Vaginal. 



The superior vesical is that part of the fcetal hypogastric artery which remains 

 pervious after birth. It extends to the side of the bladder, distributing 

 numerous branches to the body and fundus of the organ. From one of these 



1 Medico-Chirurgical Trans., vol. xvi. 



