448 BRANCHES OF INTERNAL ILIAC ARTERY. 



corpus cavernosum and the dorsal artery of the penis, are distributed to 

 the clitoris, and are named the jjr of u/i da and dorsal arteries. 



Tiie sciatic artery, the largest branch of the internal iliac trunk, 

 excepting the gluteal, is distributed to the muscles on the back of the 

 pelvis. It descends upon the pelvic surface of the pyriformis muscle 

 and the sacral plexus of nerves ; and turning backwards beneath the 

 border of that muscle, it passes between it and the superior gemellus, 

 and thus escapes from the pelvis, along w-ith the great sciatic nerve and 

 the pudic artery, at the lower part of the great sciatic foramen. Outside 

 the pelvis, this artery lies in the interval between the tuber ischii and 

 the great trochanter, covered by the gluteus maximus. 



Branches.— The sciatic arteiy gives off several branches to the external rotator 

 muscles of the thigh, on which it lies, and to the great gluteus by which it is 

 concealed. Two other.s have received special names, viz., the following : — 



(rt) The coccygeal, inclines inwards, and piercing the great sacro-sciatic liga- 

 ment, reaches the posterior surface of the coccyx, and ramifies in the fat and 

 skin about that bone. 



(/>) Tlie comes nrrvl isch'uidlci runs downwards, accompanying the sciatic nerve, 

 along which it sends a slender vessel. 



Some of the branches of this artery are distributed to the capsule of the hip- 

 joint; whilst others, after supplying the contiguous muscles, anastomose with the 

 gluteal, the internal circumflex, and the superior perforating arteries in the upi^er 

 part of the long flexor muscles of the thigh. 



The gluteal artery, the largest branch of the internal iliac, is dis- 

 tributed to the muscles on the outside of the pelvis. It inclines down- 

 wards to the great sacro-sciatic foramen, and escaping from the cavity 

 of the pelvis, between the contiguous borders of the middle gluteal and 

 tlie pyriform muscles, divides immediately into a superficial and a deep 

 branch. 



Branches. — (a) The snpcrficml branch running between the gluteus maximus 

 and gluteus medius, divides into ramifications which are most copiously distri- 

 buted to the gluteus maximus, and anastomose with the sciatic and posterior 

 sacral arteries. 



Q)) The f/<Y7^ branch, situated between the gluteus medius and gluteus minimus, 

 inins in an arched du-ection forwards, and divides into two other branches. One 

 of these, the superior branch, follows the upper border of the gluteus minimus 

 beneath the middle gluteal muscle and the tensor of the fascia lata, towards the 

 anterior iliac spine, and, after having freely supplied the muscles between which 

 it passes, anastomoses with the circumflex iliac and the ascending branches of the 

 external circumflex arteries. Tlie second or inferior branch descends towards the 

 great trochanter, supplies the gluteal muscles, and anastomoses with the external 

 circumflex and the sciatic arteries. 



{(•) A nutrient branch enters the ilium at the place where the ai-teiy emerges 

 from the pelvis. 



The ilio-lumbar artery resembles in a great measure one of the 

 lumbar arteries. It passes outwards beneath the psoas muscle and the 

 external iliac vessels, to reach the margin of the iliac fossa, where it 

 separates into a lumhar and an iliac division. The first of these ramifies 

 in the psoas and quadratus muscles, communicating with the last 

 lumbar artery, and furnishing iDranches to the vertebral canal. The 

 second or iliac division, turning downwards and outwards, either in 

 the iliacus muscle or between it and the bone, anastomoses with the 

 circumflex iliac arteiy, and even with the external branches of the 

 epigastric. 



