PRACTICAL CONSIDERATIONS : FALLOPIAN TUBES. i999 



formed numerous twigs are given off to the wall of the Fallopian tube and to the 

 mesosalpinx. Those distributed to the oviduct gain the canal along its nonperitoneal 

 tract between the peritoneal reflection and, piercing the wall, break up into capillary 

 net-works within the muscular and mucous coats. The veins, which begin within the 

 walls of the tube, especially between the muscular layers, and as a subserous net-work, 

 follow the arteries and become tributary to both the uterine and ovarian trunks. 



The lymphatics, after emerging from the wall of the tube, form three or four 

 stems that accompany the blood-vessels and pass in front of the attached border of 

 the ovary. For the most part they follow the ovarian lymphatics through the sus- 

 pensory ligament to become finally tributary to the lumbar lymph-nodes surrounding 

 the aorta. It is probable that some of the lymphatics of the tube communicate with 

 those of the fundus uteri (Poirier, Bruhns). 



The nerves supplying the Fallopian tube, numerous and chiefly sympathetic 

 fibres, follow the arteries and, therefore, reach the oviduct from both the ovarian and 

 the uterine plexus. Within the subserous tissue they form a peritubal plexus from 

 which twigs penetrate the wall of the canal and are distributed principally to the 

 muscular tissue, some filaments taking part in the production of a subepithelial plexus 

 within the mucous membrane (Jacques). 



Development and Changes. — The early development of the oviducts is 

 direcdy associated with that of the embryonal Miillerian ducts (page 2038), the 

 unfused portions of which the tubes represent. The margin of the abdominal open- 

 ing (the persistent original evagination from the primary body-cavity or ccelom) is 

 at first cushion-like, but soon exhibits indentations which, by the fifth foetal month, 

 develop into distinct fimbriee. At birth, while smaller, the latter possess their charac- 

 teristic appearance and are lined by ciliated columnar epithelium that covers the 

 plications of the tube. The upper (outer) segment of the oviduct participates in the 

 migration incident to the descent of the ovary, lying for a time within the abdomen 

 above the pelvic brim. In contrast to the ovary, the tube early acquires its definite 

 form, in the new-born child presenting its chief characteristics, although it is more 

 twisted than later and the fimbriae are still small ; the plication of the mucosa, how- 

 ever, is almost fully developed. During childhood, beginning at the uterine end, the 

 tube becomes less tortuous and the fimbriated extremity assumes its definite propor- 

 tions. In advanced age, the oviduct suffers atrophy, losing its former tortuosity, the 

 infundibulum becoming flaccid and the fimbriae shrivelled. Owing to the atrophy of 

 the muscle its wall becomes thinner ; the ciliated columnar epithelium is replaced by 

 cubo\dal cells, the lumen narrows and in places may disappear in consequence of 

 the adhesion of the mucous folds. 



Variations. — Apart from anomalous situation depending upon malposition of the uterus and 

 ovary, in which the tube of necessity shares, the variations of the oviduct usually depend upon 

 developmental faults traceable to imperfect or aberrant formation of the Miillerian ducts. 

 Retention of the foetal tortuosity, stunted development or entire absence may affect one or both 

 tubes. Complete doubling of the oviducts may occur in association with supernumerary ovaries. 

 Occasionally partial duplication of the tube is observed, consisting of a short canal ending in a 

 diminutive fimbriated extremity in the vicinity of the infundibulum. Such accessory tubes are 

 to be referred probably to a repetition of the invagination that normally produces the infundi- 

 bulum (Nagel). Quite frequently the oviduct is beset with from one to three fringed accessory 

 openings that may lie close to the fimbriated end, or at a distance from the latter along the tube. 

 The explanation of these apertures is uncertain, although it seems most probable that they result 

 from aberrant development of the Miillerian duct, rather than as secondary perforations of the 

 tube and prolapse of its mucosa, as held by Nagel and others. 



PRACTICAL CONSIDERATIONS: THE FALLOPIAN TUBES. 



The function of the Fallopian tube is to transmit the ovum from the ovary to 

 the uterus, the ciliated epithelium of the tube favoring movement in that direction. 

 An impregnated ovum may adhere to the wall of the tube, giving rise to an ectopic 

 gestation (tubal pregnancy). Such pregnancy may occur in the ampulla, — the most 

 usual place, — in the infundibulum (tubo-ovarian pregnancy), or in the intra-mural 

 portion of the tube, — i.e., that part traversing the wall of the uterus. 



