204 



UMBILICAL VESSELS. 



Fig. 171.* and the communication with the cavity 

 n of the abdomen continues. The descent 



of the intestine into the cavity thus cir- 

 cumstanced, constitutes that species of 

 hernia which is denominated Conge- 

 nit a Lf 



The most important peculiarities in 

 the abdomen of the foetus are those con- 

 nected with the circulation of the blood. 

 The internal iliac or hypogastric arte- 

 ries are larger than the external iliacs. 

 Their main trunks are continued on 

 each side of the bladder to its fundus, 

 and proceed from it, with the ligament, 

 to the umbilicus ; when they pass out of 

 the abdomen to go along the umbilical 

 cord to the placenta. These arteries are 

 now denominated the Umbilical, and 

 are very considerable in size. After birth, as there is no cir- 

 culation in them, they soon begin to change : their cavity 

 becomes gradually obliterated, and they are converted into 



* Diagram of the circulation of the human foetus. 1, 1, Umbilical arteries. 

 2, Umbilical vein. The blood of the umbilical vein is partly distributed to the 

 liver, in the right tube of which it becomes mixed with the blood of the porta, 

 and in part passes directly by the ductus venosus 3, to the vena cava inferior, 4. 

 5, Vense cava; hepaticse or hepatic veins. 6, Superior cava. 7, Right auricle. 

 8, Pulmonary veins. 9; Left auricle. 10. Left ventricle. 11, Ascending aorta 

 or left arch of the aorta. 12, Vessels to the head and upper extremities. 13, Right 

 ventricle. 14, Ductus arteriosus, or right aortic arch. 15, Descending aorta. — p. 



t These interesting circumstances respecting the original situation of the tes- 

 ticle, and its descent into the scrotum, were discovered and elucidated by Haller, 

 Hunter, Pott, Camper, and several other very respectable anatomists and sur- 

 geons. There is, however, a difference of opinion between some of them, as to 

 the time when the testicle leaves the abdomen. Haller thought the testicles 

 were seldom in the scrotum at birth. Hunter and Camper found them so 

 generally. 



It has been suggested that there are some national peculiarities in this respect ; 

 that amongst the Hungarians, for example, the testicles often remain above the 

 abdominal ring until near the age of puberty. 



The student will find an interesting description of the situation of the testis, 

 and its descent in the foetus, in the " Observations on certain parts of the Animal 

 Economy," by John Hunter. 



