ILIO-LUMEAR AND LATERAL SACRAL ARTERIES. 



449 



Varieties.— Tlie ilio -lumbar ai-tery sometimes arises from the intemal iliac 

 above the division of that trunk : and more rarely from the common iliac. The 

 iliac and lumbar portions sometimes arise separately from the parent trunk. 



Fig. 237. — Arteries of the Back 

 OF THE Pelvis and Upper 

 Part of the Thigh (from 

 Tiedemann). ^ 



o, crest of the ilium ; h, tuber- 

 osity of the ischium and lower 

 attachment of the gi'eat sacro- 

 sciatic ligament ; c, great tro- 

 chanter ; d, integument round the 

 anus; e, great sciatic nerve; 1, 

 trunk of the gluteal artery as it 

 issues from the great sacro-sciatic 

 foramen, the superficial branches 

 cut short, the deep arch seen jjass- 

 ing round on the upper part of 

 the gluteus minimus muscle ; 2, 

 placed on the great sacro-sciatic 

 ligament, points to the pudic artery 

 at the place where it winds over 

 the back of the spine of the ischium ; 

 2', the continuation of the artery 

 towards the periuajum on the in- 

 side of the tuberosity and ramus 

 of the ischium ; 3, 3, the sciatic 

 artery, the lapper figure pilaced on 

 the pyriformis muscle, the lower 

 on the great sciatic nerve ; 4, 4', 

 tirst perforating branch of the 

 femoral anastomosing with the pos- 

 terior branch of the internal circum- 

 flex artery, which ajjpears between 

 the quadratus and the abductor mus- 

 cles ; 5 and 6, part of the second 

 and third perforating arteries. 



Fig. 287. 



"When the lowest of the lumbar arteries is wanting it is replaced by a branch 

 from the ilio-lumbar, which is increased in size, and by a small offset from the 

 middle sacral artery. 



The lateral sacral arteries are usually two in number on each side, 

 though occasionally they are united into one. The two arteries arise 

 close together from the posterior division of the internal iliac. One is 

 distributed upon the upper, and the other upon the lower part of the 

 sacrum. 



Both arteries pass downwards, at the same time inclining somewhat 

 inwards, in front of the pyriform muscle and the sacral nerves, which 

 they supply with twigs, and reach the inner side of the anterior sacral 

 foramina. Continuing to descend, the lower one approaches the middle 

 line, and anastomoses with the middle sacral artery. 



Branches. — The lateral sacral ai-teries give off a series of branches which enter 

 the anterior sacral foramina. Each of these, after having furnished within the 

 foramen a spinal branch, which ramifies on the bones and membranes in the 

 interior of the sacral canal, escapes by the corresponding posterior sacral foramen, 

 and is distributed upon the dorsal surface of the sacrum to the skin and 

 muscles. 



VOL. I. a n 



