EXTERNAL ILIAC ARTERY. 321 



anastomoses with the internal circumflex, and sends a branch through the 

 notch in the acetabulum to the hip joint. Within the pelvis the obturator 

 artery gives off a branch to the iliacus muscle, and a small ramuscule which 

 inosculates with the epigastric artery. 



The LATERAL SACRAL ARTERIES are generally two in number on each 

 side ; superior and inferior. The superior passes inwards to the first sacral 

 foramen, and is distributed to the contents of the spinal canal, from which 

 it escapes by the posterior sacral foramen, and supplies the integument on 

 the dorsum of the sacrum. The inferior passes down by the side of the 

 anterior sacral foramina to the coccyx ; it first pierces and then rests upon 

 the origin of the pyriformis, and sends branches into the sacral canal to 

 supply the sacral nerves. Both arteries inosculate with each other and 

 with the sacra media. 



The GLUTEAL ARTERY is the continuation of the posterior trunk of the 

 internal iliac : it passes backwards between the lumbo-sacral and first lum- 

 bar nerve through the upper part of the great sacro-ischiatic foramen and 

 above the pyriformis muscle, and divides into three branches, superficial, 

 deep superior, and deep inferior. 



The Superficial branch is directed forwards, between the gluteus maxi- 

 mus and medius, and divides into numerous branches, which are distri- 

 buted to the upper part of the gluteus maximus and to the integument of 

 the gluteal region. 



The Deep superior branch passes along the superior curved line of the 

 ilium, between the gluteus medius and minimus to the anterior superior 

 spinous process, where it inosculates with the superficial circumflexa ilii 

 and external circumflex artery. There are frequently two arteries which 

 follow this course. 



The Deep inferior branches are several large arteries which cross the 

 gluteus minimus obliquely to the trochanter major, where they inosculate 

 with the branches of the external circumflex artery, and send branches 

 through the gluteus minimus to supply the capsule of the hip joint. 



Varieties in the Branches of the internal iliac. The most important of 

 the varieties occurring among these branches is the origin of the dorsal 

 artery of the penis from the internal iliac or ischiatic. The artery in this 

 case passes forwards by the side of the prostate gland, and through the 

 upper part of the deep perineal fascia. It would be endangered in the 

 operation of lithotomy. The dorsal artery of the penis is sometimes de- 

 rived from the obturator, and sometimes from one of the external pudic 

 arteries. The artery of the bulb, in its normal course, passes almost 

 transversely inwards to the corpus spongiosum. Occasionally, however, 

 it is so oblique in its direction as to render its division in lithotomy un 

 avoidable. The obturator artery may be very small or altogether want- 

 ing, its place being supplied by a branch from the external iliac or epi- 

 gastric. 



EXTERNAL ILIAC ARTERY. 



The external iliac artery of each side passes obliquely downwards along 

 the inner border of the psoas muscle, from opposite the sacro-iliac sym- 

 nhysis to the femoral arch, where it becomes the femoral artery. 



Relations. It is in relation in front with the spermatic vessels, the 



