598 ABDOMEN 



third and fourth sacral nerves pass to its walls. Whilst the pelvic fascia 

 is being removed from the sacral region care must be taken not to injure the 

 sacro- pudenda! and coccygeal plexuses and their roots and the sympathetic 

 cord, which all lie immediately behind the fascia. The lateral sacral 

 arteries will serve as useful guides, for as they run medially, from the 

 posterior division of the hypogastric artery, they lie in front of the sacral 

 plexus, and as one or other of them descends along the front of the 

 sacrum it lies immediately to the lateral side of the sympathetic cord and 

 across the roots of the sacral nerves as they issue from the anterior sacral 

 foramina. 



Pelvic Blood - Vessels. The pelvic arteries are the 

 following : 



1. The hypogastric and its branches (upon each side). 



2. The middle sacral } , ,. , . 



3. The superior hsemorrhoidal ) (near the median P lane >' 



Arteria Hypogastrica (O.T. Internal Iliac Artery). The 



hypogastric artery is the medial terminal branch of the 

 common iliac artery; it is a short, wide vessel, about one 

 and a half inches long (37 mm.) and much smaller in the 

 adult than the external iliac artery. It commences opposite 

 the sacro-iliac articulation, at the level of the lumbo-sacral 

 articulation ; it runs downwards and backwards in the pelvis, 

 and ends, near the upper border of the great sciatic notch, 

 by dividing into an anterior and a posterior division. 



Relations. To its lateral side are the obturator nerve, and, 

 at a higher level, the external iliac vein, which separates it from 

 the medial border of the psoas. In front is the ureter, 

 and behind is the hypogastric vein. Medially it is covered by 

 peritoneum, which separates the right artery from coils of the 

 ileum and the left from the pelvic colon. In the female 

 the ovary and the ovarian end of the Fallopian tube are 

 anterior relations of the artery and of the ureter, from both 

 of which they are separated by the parietal peritoneum. 



Condition in the Fxtus. Very different is the condition 

 of the hypogastric artery in the foetus. It is twice as large 

 as the external iliac artery. Instead of terminating at the 

 sciatic notch it runs forwards and ascends, on the posterior 

 aspect of the anterior abdominal wall, to the umbilicus, 

 through which it passes, in company with its fellow of the 

 opposite side and the umbilical vein. Outside the abdominal 

 cavity the hypogastric arteries enter the umbilical cord, and, 

 twining spirally round the umbilical vein, they reach the 

 placenta, where the impure blood which they carry is brought 

 into relation with the maternal blood. 



