432 A MANUAL OF ANATOMY 



passes between the lumbo-sacral cord and the anterior primary; 

 division of the first sacral nerve, after which it emerges through 

 the upper compartment of the great sacro -sciatic foramen above 

 the pyriformis, and breaks up into two divisions — superficial and 

 deep. The superficial division passes backwards between the 

 posterior border of the gluteus medius and the pyriformis, and 

 then enters the deep or anterior surface of the gluteus maximus 

 near its origin. Some of its branches become cutaneous by piercing 

 the muscle, and they anastomose with the posterior branches oi 

 the lateral sacral arteries from the posterior division of the internal 

 iliac. 



The deep division passes beneath the gluteus medius, where 

 it subdivides into an upper and a lower branch. The uppet 

 branch courses along the upper border of the gluteus minimus, 

 in company with the upper division of the superior gluteal 

 nerve. It supplies the ilium and adjacent muscles, and anasto- 

 moses with the deep circumflex iliac of the external iliac and the 

 ascending branch of the external circumflex of the arteria profunda 

 femoris. The lower branch passes forwards over the centre of the 

 gluteus minimus, in company with the lower division of the superior 

 gluteal nerve. It supplies the gluteus medius and gluteus minimus 

 muscles. It also gives an articular branch to the hip- joint, and a 

 branch to the digital fossa which anastomoses with the sciatic, 

 the ascending branch of the internal circumflex, and a branch of 

 the first perforating of the arteria profunda femoris. The lower 

 branch of the deep division also anastomoses with the ascending 

 branch of the external circumflex. 



The place of emergence of the gluteal artery from the pelvis! 

 is indicated as follows : the thigh being rotated inwards, draw £| 

 line from the top of the great trochanter -to the posterior superion 

 iliac spine, and take a point in this line at the junction of the innei 

 third and outer two-thirds. 



The gluteal vein terminates in the internal iliac vein. 



Sciatic Artery. — ^This vessel arises from the anterior division o 

 the internal iliac artery. It descends, usually behind the interna i 

 pudic, upon the pyriformis and sacral nerves, and emerges througl: 

 the lower compartment of the great sacro-sciatic foramen below thf 

 pyriformis. It then passes between the great trochanter and tubef 

 ischii, lying under cover of the gluteus maximus, on the inm^ 

 side of the great sciatic nerve, and resting upon the gemellj^ 

 obturator internus, and quadratus femoris. On leaving this hollovl 

 it descends upon the posterior surface of the upper part of tH 

 adductor magnus, where it terminates. I 



For the intrapelvic portion of the artery, see dissection of tl 

 pelvis. 



Branches. — ^The extrapelvic branches are as follows : coccyger 

 inferior gluteal, muscular, anastomotic, articular, gluteal cutaneoi 

 and comes nervi ischiadici. 



The coccygeal branch pierces the great sacro-sciatic ligame 



