THE EXTERNAL ILIAC ARTERY. 485 



fasciae, as far as the anterior superior iliac spine. From this point the artery is con- 

 tinued backwards along- the inner margin of the iliac crest, giving branches to the 

 iliacus and lateral abdominal muscles, and ends by anastomosing with the iliac 

 branch of the ilio-lumbar artery. Some small branches also pierce the muscles 

 attached to the crest of the ilium and communicate with offsets of the gluteal 

 artery. 



From the first part of the circumflex iliac artery branches are given to the ilio- 

 psoas, and to the upper ends of the sartorius and tensor vaginae femoris muscles. 

 One considerable branch, sometimes replaced however by two or three~Bnraller ones, 

 arises near the anterior superior iliac spine, and ascends between the internal oblique 

 and transversalis muscles, supplying the abdominal wall, and anastomosing with 

 the epigastric and lumbar arteries. 



Two veins accompany the circumflex iliac artery ; these unite below into a single 

 vessel, which crosses the external iliac artery about three quarters of an inch above 

 Poupart's ligament, and joins the external iliac vein. 



Varieties. Size. In those rare cases in which the principal vessel of the lower limb is 

 continued from the sciatic branch of the internal iliac artery, the external iliac is much 

 diminished in size, and ends in the profunda artery of the thigh. 



Branches. The usual number of two principal branches of the external iliac artery may 

 be increased by the separation of the circumflex iliac into two branches, or by the addition of 

 a branch usually derived from another source, such as the internal circumflex artery of the 

 thigh, or the obturator artery, or very rarely the deep femoral artery. In one case the dorsal 

 artery of the penis was thus given off (Arthur Thomson, Journ. Anat., xix, 330). 



The deep epigastric artery occasionally arises higher than usual, as at an inch and a half, 

 or even two inches and a half, above Poupart's ligament ; and it has been seen to arise below 

 that ligament from the femoral, or from the deep femoral artery. The epigastric frequently 

 furnishes the obturator artery as already described (p. 476) ; and a few examples are recorded 

 in which the epigastric artery arose from an obturator furnished by the internal iliac artery. 

 In a single instance the epigastric artery was represented by two branches, one arising from 

 the external iliac, and the other from the internal iliac artery (Lauth). Some combinations 

 of the epigastric with the internal circumflex, or with the circumflex iliac, or with both those 

 vessels, have been noticed. 



The deep circumflex iliac artery sometimes deviates from its ordinary position. arising 

 at a distance not exceeding an inch above Poupart's ligament. Deviations in the opposite 

 direction are not so frequent, but it is occasionally found arising below the ligament, from the 

 femoral artery. 



SURGICAL ANATOMY OF THE EXTERNAL ILIAC ARTERY. 



The external iliac artery is usually tied about midway between its commencement and the 

 origin of the epigastric artery. It may be exposed by a curved incision, about four inches in 

 length, commencing about an inch above and a little outside the middle of Poupart's liga- 

 ment, and terminating about an inch above the anterior superior iliac spine. After dividing 

 carefully the integument, the abdominal muscles, and the transversalis fascia, the peritoneum (to 

 which the spermatic vessels adhere) is raised from the iliac fossa, and the artery is found at 

 the margin of the pelvis, lying along the inner border of the psoas muscle. The vein is close 

 to the artery, on its posterior and inner aspect ; the genital branch of the genito-crural nerve 

 lies on it rather to the outer side ; and the circumflex iliac vein crosses it near Poupart's 

 ligament. In order to introduce the ligature, it is necessary to divide the layer of subperi- 

 toneal tissue which binds the vessel down to the iliac fascia ; and the needle should be passed 

 from within outwards on both sides of the body. 



Collateral circulation. After ligature of the external iliac artery, blood is conveyed to 

 the lower end of that vessel through the anastomoses of the epigastric with the internal 

 mammary, intercostal, and lumbar arteries, and of the circumflex iliac with the lumbar and 

 ilio-lumbar arteries ; to the femoral trunk also by the anastomoses of the branches of the 

 deep femoral artery with the branches of the internal iliac, viz., the internal circumflex with 

 the obturator and sciatic arteries, the external circumflex \\ith the gluteal, and the perforating 

 arteries with the sciatic. 



FEMORAL ARTERY. 



The femoral artery is that portion of the artery of the lower limb which lies in 

 the upper three-fourths of the thigh, its limits being marked above by Poupart's 



i i 2 



