THE INTERNAL ILIAC ARTERY. 473 



and hepatic veins ; g, right, </', left kidney ; #", suprarenal bodies ; A, right, h', left ureter ; , portion of 

 small intestine turned to the right side, to show the veins passing from it to the portal vein ; k, urinary 

 bladder; I, is placed below the umbilicus, which is drawn to the left, and points by a line to the 

 urachus ; m, rectum. 



A, A, right auricle of heart, opened to show foramen ovale ; a probe, introduced through a divided 

 right hepatic vein and the inferior vena cava, is seen passing through the foramen ovale into the left 

 auricle ; at the lower part of the foramen is seen the Eustachian valve ; B, left auricular appendix ; 

 C, right ventricle ; D, placed on the inner surface of the left lung, points to the left ventricle. 



1, ascending aorta ; 1', back part of the arch, joined by the ductus arteriosus and crossed by the 

 left vagus nerve ; 1", abdominal aorta ; 2, pulmonary trunk ; 2', the place of division into right and 

 left pulmonary arteries and ductus arteriosus ; 3, 3, superior vena cava ; 3', right, 3", left innominate 

 vein ; 4, inferior vena cava between the junction of the hepatic veins and the right auricle ; 4', con- 

 tinuation of the inferior vena cava below ; 5, umbilical vein within the body of the fcetus,~5 x , without 

 the body, in the umbilical cord ; 5' 5', ductus venosus ; 5", 5", hepatic veins ; 6, 6', superior 

 mesenteric vein becoming portal ; 7, on the right common iliac vein, points to the common iliac 

 artery ; 7', left common iliac artery ; 8, right, 8', left umbilical artery ; 8 x , 8 x , umbilical arteries 

 in the umbilical cord ; 9, 9', external iliac arteries ; 10, right renal vessels ; 11, inferior mesenteric 

 artery. 



Ledwich). The lengths of the common and internal iliac arteries generally bear an inverse 

 proportion to each, other the internal iliac being long when the common iliac is short, and 

 vice versa. Moreover, when the common iliac is short, the internal iliac (arising higher than 

 usual) is placed for some distance above the brim of the pelvis, and descends by the side of 

 the external iliac to reach that cavity. 



The place of division of the internal iliac into its branches varies between the upper 

 margin of the sacrum and the upper border of the sacro-sciatic foramen. 



Brandies. Occasionally all the branches of the internal iliac artery arise without the 

 previous separation of that vessel into two portions (3-3 per cent., Jastschinski, "Die typi- 

 schen Verzweigungsformen der Arteria hypoerastrica," Internat, Monatschr. f. Anat., viii, 

 1891). 



In more than a fourth of R. Quain's cases a branch, most frequently the ilio-lumbar 

 artery, arose from the internal iliac trunk before its subdivision. 



Hypograstric artery. In the foetus, the hypogastric artery, retaining almost the full 

 size of the common iliac, curves forwards from that artery to the side of the urinary bladder, 

 and ascends on the anterior wall of the abdomen to the umbilicus. At that point the artery 

 takes the name of umbilical, and the vessels of the two sides, coming into contact with one 

 another, and with the umbilical vein along with which they are spirally coiled, proceed in 

 the umbilical cord to the placenta. After the cessation of the placental circulation at birth, 

 the hypogastric arteries become impervious from the side of the bladder upwards to the 

 umbilicus, and are converted into fibrous cords. These two cords, being shorter than the 

 part of the peritoneum on which they rest, cause a fold of the serous membrane to project 

 inwards ; and thus are formed two fossse at the fore part of the abdomen on each side of the 

 middle line, in one or other of which the projection of an internal inguinal hernia takes 

 place. The proximal part of the artery persists as the internal iliac, and the portion interven- 

 ing between this and the side of the bladder remains pervious, although proportionally much 

 reduced in size, and forms the trunk of the superior vesical artery. 



BRANCHES OP THE INTERNAL ILIAC ARTERY. 



1. The superior vesical artery (v) is, at its commencement, a part of the 

 hypogastric artery of the foetus which remains pervious after the changes that take 

 place subsequently to birth. It divides into numerous branches which supply the 

 apex and body of the bladder, and anastomose with the corresponding vessels of the 

 opposite side, as well as with the offsets of the inferior vesical artery. Anteriorly, 

 small twigs ascend on the urachus to the abdominal wall, and posteriorly, others 

 supply the lower end of the ureter. One or more of the hindmost branches of this 

 artery are sometimes described separately under the name of middle vesical. 



2. The inferior vesical artery (v) (vesico-prostatic), derived usually from the 

 anterior division of the internal iliac, is directed downwards to the base of the 

 bladder, where it ends in branches which are distributed to the lower part of that 

 organ, to the prostate, and to the vesiculse seminales. The branches to the prostate 

 communicate more or less freely upon that body with the artery of the opposite side, 

 and by small descending twigs also with the arteries of the perineum. It occa- 



