678 



UTERUS AND ITS APPENDAGES. 



covers the placenta, loses by degrees the cha- 

 racter of active vitality, and its tissues are con- 

 verted into molecular fat. 



Other and corresponding changes, of which 

 an account will be hereafter given (see PLA- 

 CENTA), occur in those structures in which 

 the foetal blood circulates. The profusely de- 

 veloped capillaries which ramify within the 

 villi during the early and middle periods of 

 gestation begin to suffer retrogression as the 

 time of separation approaches, and the foetal 

 blood flows in more simple and relatively fewer 

 channels, while, not (infrequently, entire villi 

 become obliterated by calcification. 



While these changes are proceeding in the 

 temporary structures that serve to connect the 

 fetus with the uterus, structures which begin 

 in part, at least, to become effete, even before 

 the offices for which they are formed have 

 been fully carried out, the tissues which are 

 to be employed in the process of expulsion 

 are as yet only ripening into full strength, 

 although they also, in turn, are about to suf- 

 fer a like retrogression, but not until the ob- 

 ject of their formation has been accomplished. 

 The contractile fibre, which constitutes the 

 principal portion of the uterine tissue, has 

 gradually, during pregnancy, advanced to that 

 more complete form which is reached com- 

 monly about the sixth month. From this pe- 

 riod probably no new development of muscular 

 fibre takes place, although that which is already 

 formed appears to increase somewhat in size 

 and power. It constitutes now a contractile 

 tissue, capable of exerting great expulsive 

 force. How easily, and in how many ways, 

 the contractile power may be evoked, has been 

 already shown. It is probable that by the 

 series of metamorphoses already enumerated 

 as occurring in the parts which connect the 

 foetus with the uterus, the entire ovum becomes 

 gradually placed in the position of a foreign 

 body within that organ ; a position which may 

 be compared to that of the food within the 

 alimentary canal. And just as the food is 

 propelled onwards, peristaltically, by irritation 

 of successive portions of the containing sur- 

 faces, until, with the subsequent cooperation 

 of muscles acting under the dominion of the 

 spinal cord, it becomes finally ejected ; so the 

 ovum is itself apparently the excitor of those 

 first peristalses in the uterus which initiate 

 labour. How these become coordinated and 

 established, and how the rhythmic periods are 

 probably determined, has been already con- 

 sidered, as well as the means by which, during 

 the further advances of the child over succes- 

 sive portions of the generative track, other 

 nerve and motor forces are added to those 

 with which the process commenced. 



ABiNORMAL ANATOMY OF THE UTERUS. 



A. Defective development. Imperfect or 

 defective development of the uterus may oc- 

 cur under two circumstances. There may be 

 either an original defect in its organisation, 

 arising from a failure of growth or imperfect 

 formation of those portions of the generative 



canal out of which the uterus is developed ; 

 or else the organ, having been regularly 

 formed during embryonic and foetal life, may 

 not have proceeded in its development, but 

 may have retained the infantile character after 

 the usual age of puberty has arrived and 



1st Class. Congenital defects. Defects of 

 this class may affect the uterus alone, or may 

 be conjoined with corresponding imperfections 

 of other organs. In order that their nature 

 and origin, as well as the possibility of their 

 occurrence, independently of any malforma- 

 tions of the other reproductive organs, may be 

 clearly understood, it is necessary to remem- 

 ber the mode in which the uterus is originally 

 constructed. Formed by the coalescence of 



Fig. 460. 



The entire internal generative organs, from a foetus of 



three months. (After J. Midler x 8.) 

 a, uterus ; b, round ligaments ; c, Fallopian tubes; 

 d, ovaries ; e, remains of Wolffian bodies. 



the inferior extremities of the ducts of Miil- 

 ler*, the uterus will be materially modified in 

 its construction according to the degree of 

 perfection of those ducts, as well as by the 

 amount of union which has taken place at 

 their lower terminations. 



Taking these particulars as affording a basis 

 for classification the malformations of the 

 uterus which are dependent upon original 

 vices of formation may be arranged in four 

 groups, viz. : 



Group 1 . The ducts of Miiller being both 

 imperfect or undeveloped, there results a 

 more or less complete absence of the uterus. 

 The examples of total absence of the uterus 

 which have been recorded are probably cases 

 in which the rudiments exist, but have been 

 overlooked, on account of their slight deve- 

 lopment ; for generally there may be traced 

 a more or less distinct fold of peritoneum ly- 

 ing behind the bladder and representing the 

 broad ligament, within which are found some 

 indications of a uterus. These rudiments 

 consist of two uterine cornua, either conjoined 

 at their lower extremities, or remaining sepa- 

 rate in their whole course. They usually oc- 

 cur under the form of two hollow rounded 

 cords or bands of uterine tissue, extending 

 upwards towards the ovaries, and united per- 

 haps at the usual seat of the uterus by cellu- 

 lar tissue, with which some uterine fibres are 

 intermixed. Sometimes one or two little 

 masses of uterine tissue are found. These 

 are either solid, or they contain a small cavity 



* See p. 642. 



