ILIAC ARTERIES AND VEINS. 491 



The EXTERNAL ILIAC ARTERY (fig. 171, /*) is the first part of the ves- 

 sel leading to the lower limb, and is contained in the cavity of the abdo- 

 men. Its extent is from the bifurcation of the common iliac to the lower 

 border of Poupart's ligament, where it becomes femoral. And its direction 

 would be indicated, on the surface of the abdomen, by a line from the left 

 of the umbilicus to the middle of the space between the symphysis pubis 

 and the front of the iliac crest. 



The vessel lies above the brim of the pelvis in its course to Poupart's 

 ligament, and is covered closely throughout by the peritoneum and the 

 subperitoneal fat. To its outer side is the psoas, except at its termination 

 under Poupart's ligament, where the muscle lies beneath it. A chain of 

 lymphatic glands is placed along the front and inner side of the artery. 



Near its origin it is crossed sometimes by the ureter ; and near Pou- 

 part's ligament the vas deferens bends down along its inner side, whilst 

 the spermatic vessels, and part of the genito-crural nerve lie on it for a 

 short distance. 



The position of the external iliac vein (/) is not the same on both sides. 

 The left vein is altogether internal to the artery ; whilst the right, though 

 internal in position on the pubes, afterwards lies beneath the arterial 

 trunk. The circumflex iliac vein crosses it nearly an inch above Poupart's 

 ligament. 



Branches. Two branches, epigastric and circumflex iliac, arise about 

 a quarter of an inch from the end of the artery, and are distributed to 

 the wall of the abdomen (p. 419, 420). 



Some small unnamed twigs are given to the psoas muscle and the lym- 

 phatic glands. 



Peculiarities in usual branches. The epigastric and circumflex branches may wan- 

 der over the lower inch and a half or two inches of the artery. 



In unusual branches. Though the trunk of the vessel is commonly free from any 

 unusual branch, it may be occupied between the middle and the end by the obtu- 

 rator artery, or by the internal circumflex artery of the thigh. 



ILIAC VEINS AND VENA CAVA (fig. 171). The larger veins of the 

 abdomen correspond so closely with the arteries, both in number, extent, 

 and connections, as to render unnecessary much detail in their descrip- 

 tion. As the veins increase in size from the circumference towards the 

 centre of the body, those most distant from the heart will be first re- 

 ferred to. 



The external iliac (r) is a continuation of the femoral vein beneath 

 Poupart's ligament. It has an extent like the artery of the same name, 

 and ends by uniting with the vein from the pelvis (internal iliac), to form 

 the common iliac vein. On the pubes it is inside its companion artery, 

 and lies between the psoas and pectineus muscles ; the left vein remains 

 internal to, but the right slips beneath its artery. 



The veins opening into it are the epigastric and circumflex iliac (p. 420). 



The common iliac vein (fig. 171, />) ascends by the side of its accom- 

 panying artery, the right almost vertically, and the left obliquely, to the 

 right side of the body of the fifth lumbar vertebra (the upper part), where 

 it blends with its fellow in one trunk the vena cava. 



The right vein is the shortest, and lies at first behind, but afterwards 

 outside the artery of the same name. The left is altogether below the 

 artery of its own side, and crosses beneath the right common iliac artery. 



Each vein -receives the ilio-lumbar, and the lateral sacral branch ; and 

 the common iliac of the left side is joined by the middle sacral vein. 



