FOETUS. 



deviates from this regular figure from va- 

 rious accidental causes, as it adapts itself 

 to the neighbouring parts, to the altitude 

 of the body, and to the position of the 

 contained child. Parts of the latter can 

 often be distinguished in the living state. 

 The small, or lower end of the uterus, is 

 placed in the pelvis; this contains the 

 greater part of the child's head, and fills 

 up the cavity so completely as to press 

 the bladder against the pubes, and the 

 rectum against the sacrum. The body 

 and fundus of the uterus, containing all 

 the rest of the child and the placenta, is 

 placed in the front of the abdomen, from 

 the pelvis upwards to the epigastric re- 

 gion, so as to be under and before all the 

 other bowels. It occupies the whole 

 space from one hip-bone to the other. 



The round ligaments, Fallopian tubes, 

 and ovaria, necessarily undergo consider- 

 able change in their situation : they be- 

 come closely connected to the uterus, as 

 that body in its enlargement extends be- 

 tween the two layers of the broad liga- 

 ments. The ovaria are particularly dis- 

 tinguished after conception by containing 

 a corpus luteum This is a firm fleshy 

 portion, distinguished by its yellowish 

 gray colour from the rest of the ovary, 

 and considered as a certain proof that con- 

 ception has taken place. If there is one 

 child, there is only one corpus luteum; if 

 two children, two of these bodies, &c. 

 The thickness of the pregnant uterus is 

 from one to two-thirds of an inch. The 

 arteries and veins of the uterus are won- 

 derfully increased in size in the pregnant 

 state, particularly opposite to the attach- 

 ment of the placenta. This change seems 

 to arise naturally from the important of- 

 fice which the vessels have to perform at 

 this period ; viz. the development and 

 nutrition of the foetus. Anatomists have 

 disputed concern' ng the muscularity of 

 the uterus ; but Dr. Hunter describes the 

 appearance of the muscular fibres, which 

 are however very faint. The mouth of 

 the uterus is closed, until the time of la- 

 bour, by a viscid glutinous substance. 



The contents of the pregnant uterus are, 

 the secundines, liquor amnii, and the foe- 

 tus. The former line the uterus, and im- 

 mediately cover the child ; they form the 

 chain of connexion and communication 

 between the bodies of the mother and 

 child, and carry on that wonderful influ- 

 ence upon which the life and health of 

 the child depend. They are divided into 

 navel-string, placenta, and membranes; 

 and, as they are expelled from the uterus 

 after the birth of ihe child, they are call- 

 ed the after-birth. 



The navel-string is a cord about two feet 

 long, made of three vessels twisted toge- 

 ther, and fixed at one end to the child's 

 navel, at the other to the placenta Its 

 vessels are an umbilical vein and two ar- 

 teries : the latter carry blood from the 

 child to the placenta," and the former 

 brings it back again. 



Placenta.. This, with the membranes, 

 makes a complete bag, lining the uterus, 

 and containing the child. It is thick, 

 fleshy, and exceedingly vascular. Its fi- 

 gure is round and flat, about an inch 

 thick, and a span in breadth. The outer 

 surface, which adheres to the womb, is 

 rough, tender, and bloody ; the inner is 

 smooth, harder, and marked by the rami- 

 fications of the vessels proceeding from, 

 the umbilical cord, which is attached to 

 this part. Its substance consists of two 

 parts intimately blended; viz. an umbili- 

 cal, or infantine, and an uterine portion. 

 The former is a continuation of the umbi- 

 lical vessels of the foetus, the latter an ef- 

 florescence of the internal surface of the 

 uterus. The foetal portion, which is by 

 far the largest part, is a regular ramifica- 

 tion of the arteries and veins of the navel- 

 string into smaller and smaller branches. 

 No communication whatever has b^en 

 discovered between these vessels and 

 those of the uterus ; so that the mode in 

 which the fostus'derives its nourishment 

 and growth must be completely hidden 

 from us. 



The uterine portion of the placenta 

 covers its convex surface in the form of a 

 thin membrane, and detaches innumera- 

 ble fine processes into the substance of 

 the part. It seems to be a portion of the 

 decid.ua. It is connected into one mass 

 with the umbilical portion, and the ves- 

 sels of the uterus are continued into it, 

 although they have no discoverable com- 

 munication with the umbilical arteries 

 and veins. 



The membranes are three in number ; 

 amnion, chorion. and decidua. 



The ammoii is firm, thin, transparent, 

 and possessing no visible vessels. It im- 

 mediately includes ihe liquor amnii and 

 child The chorion lies outside of the 

 amnion, and adheres to it ; it is transpa- 

 rent, very thin and tender, and adheres 

 externally to the decidua. 



The decidua is an efflorescence of the 

 internal coat of the uterus, produced af- 

 ter conception, in order to adapt the 

 womb for the ovum which is to enter it. 

 It is shed after every birth, or miscar- 

 riage, with the other membranes; and 

 hen e lits name. It is thicker, but more 

 delicate and tender, than the amnion or 



