572 THE ARTERIES 



Within the pelvis the artery gives off: — (1) An ihac or nutrient branch; (2) 

 a vesical branch; and (3) a pubic branch. "Without the pelvis, it divides into: — 

 (1) An external branch; and (2) an internal branch. 



A. Intra-peliHc branches. — (1) The iliac or nutrient branch ascends to the iliac 

 fossa, passing between the iliacus muscle and the l)one. It svipi)lies a nutrient 

 vessel to the ilium, and anastomoses with the internal In'anch of the iliac division 

 of the ilio-lumbar artery. 



(2) The vesical branch or branches are small vessels which run in the lateral 

 false ligament of the ])ladder to that organ, where they anastomose with the other 

 vesical arteries. 



(3) The pubic branch comes off from the obturator as that vessel is leaving the 

 pelvis by the oliturator canal. It runs upwards and inwards behind the pubes, 

 anastomosing with its fellow of the opposite side of the body, and with the pubic 

 l)ranch of the deep epigastric artery. One of the anastomosing channels between 

 the pubic branch of the obturator and pubic branch of the deep epigastric arteries 

 is sometimes of large size, a fact of surgical interest in that the enlarged vessel may 

 then run round the inner side of the femoral ring (])age 579). 



B. Extra-pelvic branches. — (1) The external branch skirts the external margin 

 of the thyroid foramen, h^ing between the ol^turator externus and the obturator 

 meml^rane. At the lower margin of the foramen it divides into two branches. One 

 branch continues its course round the lower margin of the foramen, and anasto- 

 moses with the internal branch of the obturator and with the internal circumflex. 

 The other branch turns outwards below the acetabulum, and ends in the muscles 

 arising from the tuberosity of the ischium. It anastomoses with the sciatic artery. 

 This l)ranch gives off a small twig which passes under the transverse ligament into 

 the hip-joint, Avhere it supplies the synovial membrane, the ligamentum teres, and 

 the fat in the fossa at the bottom of the acetabulum. 



(2) The internal branch runs round the inner margin of the thyroid foramen, 

 and anastomoses with the inner division of the external branch and with the 

 internal circumflex artery. It supplies branches to the ol)turator and adductor 

 muscles. 



7. THE SCIATIC ARTERY 



The sciatic artery — the larger of the terminal l:)ranches of the anterior division 

 of the internal ihac — passes over the sacral plexus and pyriformis muscle to the 

 lower part of the great sciatic foramen, where it leaves the pelvis with the pudic 

 artery, behind and external to which it lies, by passing between the pyriformis and 

 coccygeus muscles. On emerging from the great sciatic foramen in the gluteal 

 region under cover of the gluteus maximus, it descends to the inner side of the great 

 sciatic nerve, lying midway between the tuberosity of the ischium and the great 

 trochanter on the gemellus superior, obturator internus, gemellus inferior, quadratus 

 fcmoris, and upper part of the adductor magnus muscles. It anastomoses with the 

 internal circumflex artery, and superior perforating branch of the profunda. The 

 branches of the sciatic artery are divided into the intra- and extra-pelvic. 



The intra-pelvic branches are small and unimportant, and irregular in their 

 origin and (Hstribution. Thc}^ are given oft' to the levator ani, coccygeus, and 

 pyriformis muscles, the rectum, bladder, prostate gland, and vesiculse seminales. 



The extra-pelvic branches are: (1) The coccygeal; (2) inferior gluteal; (3) 

 muscular; (4) anastomotic; (5) articular; ((3) cutaneous; and (7) comes nervi 

 ischiatici. 



(1) The coccygeal is a small l)ranch Avliich glasses inwards, and, jjiercing the 

 great sacro-sciatic ligament and the gluteus maximus, is lost in the integument 

 over the lower part of the sacrum and coccyx. It gives several l)ranches to the 

 lower and internal ])art of tlie gluteus maxinuis as it passes through it. 



(2) The inferior gluteal is a fairly large branch which arises from the sciatic 

 just l)elow the coccygeal, and, turning upwards and inwards into the deep surface 

 of the gluteus maximus along with the inferior gluteal nerve, su])plies that muscle, 

 and anastomoses with the gluteal artery. 



(3) The muscular branches, varial)le in their numlier and origin, pass to the 



