650 



UTERUS AND ITS APPENDAGES. 



condition. These, up to the time of impregna- 

 tion, form the special and sole elements of 

 the muscular tissue ; yet some physiologists 

 even of the present day refuse to recognise 

 in these a muscular character, although it is 

 plain that the uterus so constructed has a 

 contractile power. The occurrence of ab- 

 ortion, sometimes at the very beginning of 

 pregnancy, the expulsion of polypi and dys- 

 menorrhceal membranes, and the painful con- 

 tractions termed uterine colic, prove that the 

 unimpregnated uterus is so endowed. This 

 non-recognition of a muscular character in 

 the uterus before pregnancy has arisen from 

 the minute size of the individual fibres, and 

 from the difficulty of explaining why tliese 

 should grow to a given point, and then cease 

 to be developed. But F. M. Kilian has 

 given a happy illustration of this point, de- 

 rived from the observation of Kolliker, that 

 the contractile fibre cells which are found in 

 the coats of the smaller blood-vessels, pre- 

 serve a relative proportionate size to those of 

 the larger ones, wherein they are more fully 

 developed. So also the contractile fibre cells 

 of the uterus proceed to a certain point of 

 development in the unimpregnated organ, and 

 there stop. And in this respect it makes 

 little or no difference whether the organ exa- 

 mined has been taken from an infant or an 

 adult. 



But when pregnancy takes place, the fibres 

 proceed to a further stage of development. 

 Their growth is now so considerable, that the 

 contractile fibre cells, instead of a length of 

 0-002 0-003"', and width of Q'002"', in the 

 fifth month, present a length of 0'06 Q-12'", 

 and width of 0'0025 O'OOG'", or even O'Ol'", 

 and in the second half of the sixth month, a 

 length of 0-1 0-25'", a width of 0'004 

 0-oby", and a thickness of 0'002 G'0028'"; 

 consequently their length is increased from 

 seven to eleven times, and their width from 

 twice to five times.* 



But in addition to this greater development 

 of pre-existing fibre cells, a new formation of 

 muscular fibre also takes place. This is ob- 

 served, according to Kolliker, chiefly in the 

 inner layers, although it may also occur in the 

 external ones. The time of this new forma- 

 tion is chiefly the first half of pregnancy, the 

 earlier forms of the fibre cells being no longer 

 discernible after the twenty-sixth week. 

 From this time onwards, the muscular coat 

 contains only colossal fibre cells. 



According to my observations, the indivi- 

 dual fibre cells increase gradually in breadth 

 throughout pregnancy, but their length is so 

 variable, that the measurements just given 

 can only be regarded as examples. The length, 

 indeed, of the greater number of fibre cells 

 after the third month cannot be determined 

 with exactitude. A great many are thrown 

 into numerous folds and contortions. Some 

 exhibit transverse wrinkles, and the majority, 

 when unbroken, end in long drawn out fila- 



* Kolliker, Manual of Human Histology, Syd. 

 Soc. vol. ii. p. 259.; and Siebold and Kolliker's 

 Zeitschrift, 1848, bd. I. p. 72. 



ments, whose terminations become inter- 

 mingled with the adjacent cells. Fine longi- 

 tudinal markings are often distinguishable, 

 and some fibres exhibit an elongated nucleus. 

 The interior of the fibre is finely granular, 

 and the margins show often a sinuous outline. 



Fig. 448. 



Fibre cells of gravid uterus fully developed. 

 Wagner.) 



(After 



The fibrous tissue uniting the several 

 layers of muscles appears also to increase 

 considerably, and towards the end of preg- 

 nancy to exhibit a distinct fibrillation. 



These muscular and fibrous elements of 

 the gravid uterus are arranged in numerous 

 thin lamellae, a good view of which may be 

 obtained by cutting a thin slice perpendicu- 

 larly out of the walls of the uterus at term. 



Fig. 449. 



Section of the entire walls of the uterus after deli- 

 very; showing the arrangement of the lamina: and 

 the divided arteries and veins lying between them. 

 (Ad Nat.)* 



By gentle traction, the laminae may be drawn 

 partly asunder. They are then seen to be 



* In order to obtain a correct representation of 

 the course of the laminae, I have here pinned out the 

 preparation under spirit, and afterwards photo- 

 graphed it for engraving, of the natural size. By 

 the stretching, the breadth of the preparation is 

 doubled, and the laminae are separated and rendered 

 more distinct. 



