834 



ILIAC ARTERIES. 



behind the ischium between its tuberosity and 

 the great trochanter of the femur, and gives off 

 as it descends numerous branches distributed 

 in the superior posterior region of the thigh. 

 Within the pelvis the artery is situate internal 

 to the sacral nerves and the pyriformis muscle, 

 external to the rectum and the peritoneum, in 

 front of the sacrum, the nerves and the attach- 

 ments of the pyriformis, and posterior and ex- 

 ternal to the pudic artery; in escaping from the 

 cavity it passes between the pyriformis and 

 ischio-coccygeus muscles, and is accompanied 

 by the pudic artery, to which it holds the same 

 relation as before, but is closer to it, and by the 

 sciatic nerve; within the pelvis it is internal 

 and anterior to the sacral plexus, but as it goes 

 out it passes between its branches, and thus 

 becomes posterior to the nerve. 



Without the pelvis the ischiatic artery corre- 

 sponds in front to the spinous process of the 

 ischium, the gemelli, with the obturator inter- 

 nus muscles, and the quadratus ; posteriorly, it 

 is covered by the gluteus maximus and the inte- 

 guments ; it is situate at first behind the sciatic 

 nerve, but as it descends it becomes internal to 

 the nerve, the distance between them increasing 

 at the same time. While behind the spinous 

 process of the ischium the ischiatic artery is 

 external to the pudic artery, and more super- 

 ficial, i.e. still posterior; but as the pudic passes 

 to the inside of the tuberosity of the bone, while 

 the ischiatic runs on its outside, the two vessels 

 immediately separate and cease to be related. 



Within the pelvis the ischiatic artery gives 

 some irregular and small branches to the rec- 

 tum, the bladder, the uterus, the vagina, the 

 cellular tissue, the pyriformis and levator mus- 

 cles ; at times it is considered as giving off 

 also the pudic, the hemorrhoidal, or obturator 

 arteries. The branches which it furnishes ex- 

 ternal to the pelvis are numerous ; among them 

 are distinguished the following : 1. Thecoccy- 

 gean branch, of considerable size, runs down- 

 ward and inward toward the coccyx, across the 

 pudic artery and posterior to it, passes through 

 the great sacro-sciatic ligament, and divides into 

 branches, which are distributed to the ligament, 

 to the gluteus, the coccygeus, and levator ani 

 muscles, to the posterior aspect of the sacrum 

 and coccyx, and to the fat and integument ; its 

 branches communicate with those of the pudic. 

 2. A considerable branch or set of branches, 

 which run outward and downward toward the 

 back of the great trochanter upon the internal 

 obturator, gemelli, and quadratus muscles, sup- 

 ply them with branches, and anastomose with 

 the circumflex (femoral) arteries. 3. A branch 

 or branches to the inferior part of the gluteus 

 maximus, prolonged through it to its insertion, 

 and then meeting the circumflex and perforating 

 arteries. 4. A branch or branches, which 

 attach themselves to the sciatic nerve, naturally 

 of small size, but regular, and remarkable for 

 the extraordinary change they undergo after the 

 interruption of the main artery of the thigh; 

 they arise about the tuberosity of the ischium, 

 and descend along the nerve giving it branches, 

 and communicating with branches from the 

 perforating arteries, which also attach them- 



selves to the nerve, whereby a chain of anasto- 

 moses is established along it, which, when the 

 main channel has been interrupted, becomes 

 amazingly enlarged and forms, as it were, one 

 remarkably tortuous vessel along the entire 

 length of the nerve. 5. A very considerable 

 branch, the termination of the artery, distri- 

 buted to the upper extremity of the flexors of 

 the leg, the biceps, &c. and of the adductor 

 muscles ; the ramifications of which communi- 

 cate with the perforating and internal circumflex 

 arteries. 



The ischiatic artery is circumstanced external 

 to the pelvis so similarly to the gluteal, that, if 

 necessary, it might be exposed during life by a 

 similar operation ; for a method of determining 

 its situation prior to operation, the reader is re- 

 ferred to the description of the pudic artery. 



4. The internal pudic artery arises from the 

 anterior division of the internal iliac, which for 

 the most part, after having given off its other 

 branches, divides into the ischiatic and the 

 pudic ; the height at which the division takes 

 place is uncertain ; at times it does not occur 

 until the trunk has descended to the sciatic 

 notch, or even escaped from the pelvis. The 

 pudic artery is smaller than the sciatic; it 

 passes downward, forward, and inward, until it 

 reaches the inferior part of the great sciatic 

 notch, through which it escapes from within 

 the pelvis in company with the ischiatic artery, 

 the pudic, and sciatic nerves ; having escaped 

 from the pelvis it crosses the extremity of the 

 spinous process of the ischium and the attach- 

 ment of the anterior sacro-sciatic ligament, and 

 returns into the cavity through the anterior 

 notch, accompanied by the pudic nerve ; having 

 re-entered the pelvis, it then runs forward, in- 

 ward, and downward internal to the tuberosity 

 of the ischium, until it reaches its anterior ex- 

 tremity, whence it continues its course upward 

 along the inside of the rami of the ischium and 

 pubis toward the arch of the pubis, and beneath 

 the latter finally divides ; the course of the 

 artery, therefore, forms a considerable curve 

 convex downward and backward, during which 

 the vessel is contained within the pelvis at its 

 commencement and its termination, and is 

 without the cavity during the intermediate part. 

 Its course is thence divided into three stages, 

 during two of which it is within, and in the 

 third without the cavity. 



The first stage of the artery's course, through- 

 out which it is contained in the pelvis, extends 

 from its origin to the lower part of the posterior 

 sacro-sciatic notch, through which it escapes 

 from the cavity ; it is of variable length, in con- 

 sequence of the variable height at which the 

 vessel arises. The relations of the artery during 

 this stage are posteriorly and externally the 

 sacral nerves, the pyriform muscle, and the 

 sacrum ; internally the peritoneum and the 

 rectum ; it is posterior and external to the fun- 

 dus of the bladder and the vesiculae seminales, 

 and anterior and internal to the ischiatic artery; 

 previous to its exit it sometimes passes between 

 the sacral nerves before forming the plexus. 

 It goes out from the pelvis below the pyriformis 

 and above the spinous process of the ischium 



