1012 SURGICAL ANATOMY OF THE ARTERIES. 



avoided, to be opened with a lancet, except in a part which is not contiguous 

 to the artery. 



When two arteries are present, instead of the ordinary single trunk, they 

 are commonly close together ; but it now and then happens that an interval 

 exists between them one being in the usual situation of the brachial, the 

 other nearer, in different degrees in different cases, to the inner condyle of 

 the humerus. There is on this account an additional reason for precaution 

 when venesection is to be performed ; and care is the more necessary, as the 

 second artery may be immediately under the vein without the interposition 

 of fascia [plate 41]. 



SURGICAL ANATOMY OF THE COMMON ILIAC ARTERIES. 



The common iliac artery (p. 418), extending in a line from the left side 

 of the umbilicus towards the middle of Poupart's ligament, and being placed 

 at its commencement on a level with the highest part of the iliac crest, may 

 be approached in an operation, by dividing the abdominal muscles to a 

 sufficient extent in the iliac region, and a little above this part of the abdo- 

 men. The incision may be made, beginning about Poupart's ligament, 

 to the outer side of its middle, and running parallel with that structure 

 towards the anterior superior spine of the hip-bone, thence curving for a 

 couple of inches towards the umbilicus. In this way the artery will be ap- 

 proached from below, but, if a tumour extends along the external iliac 

 artery, this plan of operation will be objectionable, for the swelling itself, 

 and, it may be, the adhesion of the peritoneum to its surface, will be 

 sources of serious difficulty. Should the aneurism extend upwards iu the 

 abdomen it will be best to approach the artery from the side, or rather 

 from above, not from below. The essential part of the operation, so far as 

 the abdominal muscles are concerned, is, that they should be divided to the 

 extent of five or six inches at the side of the abdomen, beginning about 

 two inches above the level of the umbilicus and ending lower than the 

 iliac spine, the incision being curved outwards towards the lumbar region. 

 Sir P. Crampton, in an operation to tie this artery, divided the muscles from 

 the end of the lowest rib, straight down nearly to the iliac crest, and thence 

 forward a little above the border of the bone as far as its spine. * This plan 

 is well devised for the object. 



The fascia behind the muscles (fascia transversalis) is to be cut through 

 with care, and the peritoneum is to be raised from that and the iliac fascia, 

 as well as from the subjacent membrane (sometimes containing fat) which is 

 interposed between the serous and the fibrous membranes. With the peri- 

 toneum the ureter will be raised, as this adheres to it. 



The artery will be seen on the last lumbar vertebra ; and, on the right 

 side of the body, large veins will be in view in close connection with it, 

 viz., both common iliac veins, and the commencement of the lower 

 vena cava [plate 55]. It will be remembered, that in some cases (with- 

 out transposition of the viscera, as well as with that condition) the iliac 

 veins are joined on the left instead of the right side; and that in 

 another small class of cases the junction of those veins is delayed, so to 

 say [plate 58, figs. 1, 2, 3]. The effect of either of these conformations of 

 the venous system would be to give to the artery on the left side much 

 more than the usual complication with veins. Lastly, the thin subserous 

 membrane covering the artery is divided without any difficulty, to admit 

 the passage of the ligature. 



* Med. Chir. Trans., vol. xvi. 



