FALLOPIAN TUBE OR OVIDUCT (ABNORMAL ANATOMY). 



621 



respect have led to a division of cases of tubal 

 gestation into three varieties, viz. tubo-ovarian, 

 tubal, and interstitial. 



In the first variety, graviditas lubo-ovaria, 

 the ovum becomes developed in a sac, of 

 which a principal portion appears to be fur- 

 nished by the hypertrophied walls of the 

 infundibular end of the tube, and the proper 

 tissue of the ovary combined. In the second, 

 graviditas tubaria, the developed ovum occu- 

 pies some part of the canal of the free portion 

 of the oviduct ; while in the third, graviditas 

 interstitialis, the seat of development of the 

 ovum is that part of the tube which traverses 

 the uterine walls. 



In the first, or tubo-ovarian variety, the 

 parts supplying the principal foundation of the 

 cyst, which surrounds the foetus, are in the 

 first instance probably chiefly normal struc- 

 tures ; and it is easy to understand how, 

 during the progress of growth of the ovum, 

 when the limit of expansibility of these parts 

 has been reached, there may be superadded 

 to them materials for the extension and fur- 

 ther growth of the cyst walls ; and in this 

 way are apparently formed these large sacs, or 

 artificial uteri, which have been sometimes 

 observed to surround a fully developed foetus, 

 and which in the course of their growth have 

 come to include omentum, mesentery, or in- 

 testine, and other portions of the abdominal 

 viscera or parietes, by which the sides of the 

 sac become strengthened and enlarged. 



As in the case of ovarian gestation for- 

 merly described, so in the varieties termed 

 ovario-tubal, it is only when death has taken 

 place during the early stages of formation of 

 these embryo-bearing cysts that the exact 

 nature and relation of the parts originally 

 composing them can be made out. Hence the 

 difficulty of determining, in more advanced 

 stages of gestation, when other parts have 

 been superadded, in what precise situation 

 the development of the ovum was commenced. 

 Anil hence the probability that some at least 

 of those cases which have been recorded from 

 time to time as examples of the foetus deve- 

 loped in the cavity of the abdomen, and among 

 the intestines (graviditas abdominalis), may 

 have been originally cases of the tubo-ovarian 

 variety, in which the cyst walls, commencing 

 their formation by the artificial union of the 

 expanded termination of the oviduct with a 

 portion of the ovarian parietes, have in the 

 course of their growth come to include many 

 other parts. 



The second variety, which includes all cases 

 strictly termed tubal (graviditas tubaria), con- 

 stitutes by far the most common of all the 

 forms of extra-uterine gestation. Here the 

 ovum is developed within some part of the 

 free portion of the tube, whose walls appear, 

 from the examples which most of our mu- 

 seums furnish, to be capable of a very limited 

 degree of expansion in most individuals. 

 Hence, when the ovum has attained to a cer- 

 tain size, and usually by the time that the 

 second or third month of gestation has been 

 reached, rupture of the tubal wall occurs, 



followed by rapid death from hasmorrhage. 

 And thus the parts are usually obtained for 

 examination in such a state as to leave no 

 room for question regarding the precise seat 

 which the ovum occupies, and the nature of 

 the parts enclosing it. For in these cases of 

 early rupture the tube has contracted no 

 adhesions with surrounding parts, and the 

 walls of the embryo-bearing sac are formed 

 of the parietes of the oviduct alone. 



The third variety of tubal gestation, distin- 

 guished by M. Breschet under the title of 

 Gratiditas in uteri substantia; and by Profes- 

 sor Mayer, of Bonn, as Graviditas interstitialis, 

 has been made known, particularly by an essay 

 of the former devoted to this subject.* 



This variety differs from the last mentioned 

 chiefly in the circumstance, that the seat of 

 development of the ovum is that portion of 

 the canal of the tube which passes through 

 the solid walls of the uterus. Here the sac 

 surrounding the foetus is formed in a great 

 measure at the expense of the proper uterine 

 tissues, and consequently the parietes of these 

 cysts exhibit under the microscope a very 

 different composition from that which the 

 tube walls show in the*second variety. 



In interstitial cases the walls of the sac 

 surrounding the ovum sometimes attain in 

 parts a thickness nearly equal to that of the 

 gravid uterus. On section of these portions 

 the appearance which they present is precisely 

 similar to that of the gravid uterus itself. 

 There is here seen precisely the same arrange- 

 ment of large vascular openings, being the 

 divided canals or sinuses which everywhere 

 permeate the solid walls, in whose composi- 

 tion may be traced the same abundance of 

 smooth muscular fibre, as in the ordinary 

 gravid uterus. 



Within such a sac, formed out of the walls 

 of the tube in the first instance, and in the 

 case of this third variety further strengthened 

 by the addition of a large quantity of tissue 

 derived from the uterus, the ovum lies, pre- 

 senting its ordinary character of an external 

 chorion and inner amnion ; the foetus or 

 embryo itself, according to the period of ges- 

 tation, being perfectly formed. The walls of 

 the sac, being in this case usually much 

 stronger than when the ovum lies nearer to 

 the distal end of the tube, resist pressure for 

 a longer time, and consequently the foetus 

 may attain a greater growth. 



One of the most interesting questions con- 

 nected with this subject is, whether a decidua 

 is here formed. Schroeder van der Kolk, in 

 his recent most valuable work on the struc- 

 ture of the Placenta f, answers the inquiry in 

 the affirmative, in contradiction to the state- 

 ment of VirchowJ, by whom it is asserted 

 that in the case of tubal gestation no decidua 



* Memoire sur une nouvelle espiice de grossesse 

 extra-uterine. Par M. Breschet. 



| Waarnemingen over het Maakscl van de Mcn- 

 schelijke Placenta. Amsterdam, 1851, p. 88. et seq. 



J Virchow, ueber die Puerperal Krunkheiten 

 Verhand. der Ges. fur Geburtshelfe. Berlin, 1848, 

 B. III. s. 180. 



