ILIAC ARTERIES. 



829 



the sacro-iliac articulation or of the lateral part 

 of the sacrum, as it may be, inclining backward 

 and outward, and describing a curve concave 

 forward, until it reaches the superior part of the 

 great sciatic notch, where it usually divides ; 

 this however is by no means uniform, the point 

 of its division ranging between the brim of the 

 pelvis and the notch. The internal iliac is an 

 artery of great size, but in the adult smaller 

 than the external ; its course is somewhat tor- 

 tuous and short, from one and a half to two and 

 a half inches. 



During its descent the artery is placed before 

 the lumbo-sacral nerve, on the left side before 

 the primitive iliac vein, and pn both before the 

 sacro-iliac articulation or the lateral part of the 

 sacrum. Before it are in the male the bladder 

 or its lateral connections, in the female the 

 uterus and its broad fold of peritoneum ; ex- 

 ternally the artery corresponds to the internal 

 iliac and the commencement of the primitive 

 iliac vems, to the inside of the psoas magnus 

 muscle, to the brim of the pelvis, to the obtu- 

 rator nerve, which it crosses nearly at right 

 angles, to the lumbo-sacral and first of the 

 anterior branches of the sacral nerves, and to 

 the superior attachment of the pyriformis 

 muscle : the ilio-lumbar artery is also external 

 to the internal iliac, between it and the wall of 

 the pelvis. Internal to it are the peritoneum, 

 the rectum with its mesentery, and the superior 

 hemorrhoidal vessels, (these parts being nearer 

 to the artery upon the left than the right,) and 

 the small intestine when in the pelvis. 



The external iliac vessels are above, before, 

 and external to the internal.* In the foetus the 

 condition of the internal iliac differs remarkably 

 from that which it presents in after life ; in it 

 both in size and direction this artery appears the 

 continuation of the primitive trunk, exceeding 

 the external as much as afterward it is exceeded 

 by it. It is the channel which conveys the blood 

 to the placenta, and it is generally entitled the 

 " hypogastric or umbilical artery ;" " placental" 

 would certainly be preferable. It passes from 

 the primitive iliac or rather from the aorta, for 

 there the primitive iliac appears only the com- 

 mencement of the placental artery, downward 

 and at first outward as far as the sacro-iliac 

 articulation, where it gives off the external 

 iliac artery, then forward to the side of the 

 bladder, descending but little into the pelvis 

 and at the same time giving off pelvic branches; 

 it next changes its direction and ascends in- 

 clining inward toward the umbilicus, at first by 

 the side of the bladder and then in the anterior 

 abdominal wall, between the peritoneum and 

 the rectus muscle or its sheath, and on either 

 side of the urachus; thus forming a curve 

 convex downward through the concavity of 

 which pass the vas deferens or round ligament 

 before, the ureter posteriorly and the rectum, 

 the extremity of the ilium and the appendages 

 of the uterus in the mean space. Having reached 

 the umbilicus the artery escapes through it 

 from the body of the foetus and is conducted 



* This is to be understood to refer to the recum- 

 bent posture ; in the erect posture the external are 

 not superior to the internal vessels. 



by the umbilical cord to the placenta ; during 

 their transit to the placenta the arteries at the 

 very early periods of utero-gestation, are straight, 

 but afterwards, in proportion as the develope- 

 ment advances, they become tortuous, and are 

 twined round the umbilical placental vein, 

 whence the length of the arteries exceeds that 

 of the cord which varies from one to two feet. 

 At the placenta the two arteries are connected 

 by a considerable anastomosis, and divide into 

 numerous branches, which subdivide minutely 

 in the lobes of that structure, the ramifications 

 of the several lobes being distinct from each 

 other; ordinarily the two vessels are distinct 

 until they approach the placenta, but they have 

 been found to unite into a single one before 

 escaping from the abdomen of the foetus.* 

 The placental arteries give off within the body 

 of the foetus branches similar in number and 

 destination with those of the primitive iliac of 

 the adult, but in a rudimental condition ; 

 between the summit of the bladder and the 

 umbilicus however they do not furnish branches, 

 and hence, the circulation through them be- 

 tween these points ceasing at birth, they be- 

 come obliterated to the same extent and 

 connected into impervious cords, known by the 

 name of umbilical ligaments ; these hold the 

 same course and relation with the original 

 vessels, and are less distinct in proportion to 

 the age of the subject ; they are covered upon 

 their abdominal aspect by the peritoneum, 

 which is reflected upon them to a greater or 

 less extent according to the subject, and thereby 

 forms triangular falciform folds, the base of 

 which is below in the iliac fossa, and the apex 

 above toward the umbilicus, and in the free 

 edge of which the ligament is contained. At 

 a point intermediate to the brim of the pelvis 

 and the upper part of the sacro-sciatic notch the 

 internal iliac artery divides into branches ; these 

 are numerous, amounting altogether in the male 

 to nine, and in the female to eleven ; but in 

 their mode of origin they vary very much, 

 arising sometimes separately, sometimes by 

 common trunks, but for the most part from, 

 two, into which the iliac divides ; these are an 

 anterior one giving off the hemorrhoidal, the 

 umbilical, the vesical, the uterine, the vaginal, 

 the sciatic and internal pudic, and a posterior, 

 from which arise the ilio-lumbar, the lateral 

 sacral, the obturator and the gluteal. Another 

 diversity in the mode of their origin is that of 

 the obturator from the epigastric or external 

 iliac. 



The branches of the internal iliac are arranged 

 either into four sets, viz. posterior, anterior, 

 internal, and inferior,f or into two, internal and 

 external,} the former distributed within, the 

 latter without the pelvis ; the latter seems the 

 more simple division, and is the one which will 

 be adopted in this article. 



The internal branches are in the male five, 

 in the female seven ; they are as follow 



1 . The iliolumbar artery varies in size and ori- 

 gin ; for the most part it arises from the posterior 



* Cloquet. 

 t Cloquet. 

 Harrison. 



