482 THE ARTERIES OF THE ABDOMEN. 



ascending branch of the external circumflex artery, as well as with the deep 

 circumflex iliac by means of branches which perforate the origin of the gluteus 

 medius, and ascend over the iliac crest. The inferior branch crosses the middle of 

 the gluteus minimus, distributes offsets to the smaller gluteal muscles and the hip- 

 joint, and anastomoses with the external circumflex and sciatic arteries. 



Variety. One instance is recorded in which the gluteal artery was replaced by a large 

 branch arising from the femoral and passing outwards and backwards to reach the gluteal 

 muscles (F. T. Roberts). 



9. The ilio -lumbar artery (v) resembles in a great measure one of the lumbar 

 arteries. It is a short vessel which passes outwards, between the obturator nerve and 

 the lumbo-sacral cord, to the upper end of the ilio-pectineal line, where it divides, 

 behind the inner margin of the psoas muscle, into lumbar and iliac branches. 



The lumbar or ascending branch turns upwards under cover of the psoas, to 

 which and to the quadratus lumborum it is mainly distributed, and anastomoses 

 with the lower lumbar arteries. A spinal branch is sent inwards through the last 

 intervertebral foramen, and is distributed like the spinal offsets of the lumbar 

 arteries. 



The iliac or transverse branch is directed outwards into the iliac fossa, and 

 ramifies partly beneath, partly on the surface of the iliacus muscle, giving offsets 

 to the bone, and forming anastomoses with the obturator, circumflex iliac, and 

 lumbar arteries. 



Varieties. The ilio-lumbar artery frequently arises from the internal iliac above the 

 division of that trunk, more rarely from the common iliac. The iliac and lumbar portions 

 sometimes arise separately from the parent trunk. 



10. The lateral sacral arteries (v) are usually two in number on each side, 

 although occasionally they are united into one. They arise close together from the 

 posterior division of the internal iliac. Both arteries incline somewhat inwards and 

 descend on the front of the sacrum, internal to the anterior sacral foramina. The 

 superior artery is confined to the upper part of the sacrum ; the inferior passes 

 downwards to the front of the coccyx, and terminates by anastomosing with offsets 

 of the middle sacral artery. 



From the lateral sacral arteries small offsets proceed outwards to the pyriformis 

 and coccygeus muscles, and to the sacral nerves, anastomosing with one another 

 round the foramina. Others are directed inwards and anastomose with branches of 

 the middle sacral artery. The largest branches pass backwards into the anterior 

 sacral foramina, supply twigs to the sacral canal, and are continued through the 

 posterior foramina to the muscles and integuments on the back of the sacrum, 

 anastomosing with the gluteal and sciatic arteries. 



EXTERNAL ILIAC ARTERY. 



The external or anterior of the two arteries resulting from the division of the 

 common iliac forms a large continuous trunk, which extends downwards in the limb 

 as far as the lower border of the popliteus muscle, but, for convenience of descrip- 

 tion, it is named in successive parts of its course external iliac, femoral, and 

 popliteal. 



The external iliac artery (9-10 mm.) is placed within the abdomen, and extends 

 from the bifurcation of the common iliac to the lower border of Poupart's ligament, 

 where the vessel enters the thigh, and is named femoral. It is larger than the 

 internal iliac, and measures usually from three and a half to four inches in length. 

 Inclining obliquely outwards, its course, together with that of the common iliac 



