THE FALLOPIAN TUBES. i997 



comparatively straight and constitutes the isth?nus (isthmus tubae uterinae), about 3.5 

 cm. {iy% in.) in length and from 3-4 mm. in diameter. Throughout the succeeding 

 8 cm. (3^ in.) of the tube, known as the ampulla (ampulla tubae uterinae), the 

 diameter gradually increases (from 6-8 mm. ) until the canal suddenly expands into 

 the terminal trumpet-shaped infiindibulum. The margins of the latter are prolonged 

 and slit up into long, irregular processes, xhejimbrits, from 10-15 mm. in length, the 

 rQsnXtWig Jimbriated extremity of the tube resembling, when examined in fluid, an ex- 

 panded sea-anemone (Nagel). One of the fimbriae (fimbria ovarica) is usually longer 

 than the others, attached to' the free border of the mesosalpinx and stretches towards 

 the ovary, the tubal pole of which it often, but by no means always, reaches. The 

 lumen of the oviduct varies greatly at different points. Beginning at the lateral angle 

 of the uterine cavity as a minute, inconspicuous opening (ostium uterinum tubae), 

 commonly obscured by mucus and about i mm. in diameter, the canal traverses the 

 uterine wall (pars uterina) and gains in size and longitudinal folds, so that on cross- 

 section the isthmus presents a stellate lumen. Within the ampulla the plications of 

 the mucous membrane become progressively more marked, appearing in transverse 

 sections as a complex figure of primary and secondary folds (Fig. 1695) that greatly 

 encroach upon the calibre of the tube. The folds are continued into the infundibulum 

 and onto the inner side of the fimbriae. The outer or ovarian end of the oviduct 

 opens directly into the peritoneal cavity by a small aperture (ostium abdominale 

 tubae), 2 mm. or less in diameter, that lies at the bottom of the infundibulum and is 

 produced by local contraction of the muscular tissue of the wall of the tube, a special 

 sphincter, however, not being demonstrable. The mucous lining of the oviduct is 

 continued from the infundibulum onto the fimbriae, the line of transition into the peri- 

 toneum following the bases and outer sides of the fringes. The exceptional relation 

 of the tubal lining to the serous membrane, this being the only place in the body 

 where a mucous tract opening onto the exterior communicates with a closed serous 

 sac, is referrible to the similar original relation of the embryonal Miillerian duct from 

 which the Fallopian tube is directly derived (page 2038). 



Course and Relations. — Since each Fallopian tube occupies the free border of 

 the broad ligament, changes in the position of the uterus affect the course of the 

 oviduct. From the upper angle of the uterus the tube may, therefore, first pass out- 

 ward towards the ovary in a strictly transverse direction, or describe a gentle forward 

 or backward curve, depending upon the position of the fundus uteri, this part of the 

 tube, however, never being tortuous. On gaining the uterine or lower pole of the 

 ovary, it there bends upward and winds obliquely, from below upward and backward, 

 across the median surface of the ovary, close to the anterior border and tubal pole, to 

 the convex posterior margin, where the tube bends sharply downward, its fimbriated 

 end being in relation with the lower and back part of the median surface. When in 

 its usual position, the ovary is, thus, partly covered not only by the tortuous oviduct 

 itself, but also necessarily by the mesosalpinx in which the tube lies, so that when 

 viewed from above the ovary is often entirely hidden by the Fallopian tube and the 

 attached portion of the broad ligament. In consequence of this arrangement, the 

 ovary is partly surrounded by a hood of serous membrane and lies within a pocket, 

 known as the bursa ovarii, which may facilitate the entrance of the liberated ova into 

 the Fallopian tube. In its course from the uterus to the ovary the oviduct lies in 

 front of and generally parallel with the utero-ovarian ligament and is overlaid by the 

 coils of the small intestine. As the tube ascends and arches over the ovary, the 

 . intestinal coils cover its medial surface, the sigmoid colon also occasionally being in 

 relation on the left side. In formalin-hardened subjects, with otherwise normal pel- 

 vic contents, we have so often found the termination of the Fallopian tube lying away 

 from the ovary, that Merkel's suggestion, that the assumed constant close relation 

 between the fimbriated extremity and the ovary may sometimes, at least temporarily, 

 be wanting during life, seems well founded. 



Structure. — The wall proper of the Fallopian tube, consisting of the mucous 

 and muscular coats, lies embedded within the loose connective tissue of the broad 

 ligament (^tunica adventitia') surrounded by the peritoneum, which completely invests 

 the tube with the exception of the narrow interval through which the tubal vessels 

 and nerves pass. The wall is thickest and firmest in the isthmus, less so in the 



