STRUCTURE OF UTERIXE WALLS. 465 



the peritoneum. Tho fibres of the subperitoneal layer are much mixed 

 with areolar tissue, especially about the middle of the anterior and 

 posterior surfaces of the uterus, in which situation many of the super- 

 ficial fibres appear to have as it were a median attachment from which 

 they divera:e. The fibi-es of the intermediate layer, which is compara- 

 tively thin, begin chiefly on the back of the uterus, and stretch over 

 the fundus and towards the sides, running somewhat irregularly between 

 the blood-vessels. Tlie iivier tai/er, which is much the thickest of the 

 three, consists of bands of fibres which are disposed with comparative 

 regularity in its upper part, being arranged there in numerous con- 

 centric rings round the openings of tho two Fallopian tubes, the widest 

 circles of the two series meeting from opposite sides in the middle of 

 the uterus. In the lower part of the body, and in the cervix the 

 internal fibres run more transversely, crossing each other at narrow 

 angles in the most various directions. They form the so-called sphinc- 

 ters of the OS internum and os externum. At the neck, however, there 

 are also longitudinal fibres within the strong transverse fibres of the 

 layer now described. (Helie, Rech. sur la dispos. des fibres musculaires 

 de I'uterus, Paris, 1869.) 



The long spindle-shaped cells of the uterine muscular tissue are very 

 closely united together by cement substance, forming bundles which 

 are again connected by areolar tissue. The fibre-cells possess distinct 

 oval nuclei ; they are about yfoth of an inch in length in the unira- 

 pregnated uterus, but attain sometimes the length of J^ th of an inch 

 in the gravid condition. 



Mucous Membrane. — The mucous membrane lining the cavity of 

 the body of tlie uterus differs greatly from that of the interior of "the 

 cervix, a marked line of distinction separating the two parts at the 

 isthmus. 



Tlie memhrane of the cervix is much firmer than that of the body. 

 Between the rugae of the so-called arhor vifne there are numerous folii- 

 cular glands, which are lined with cubical epithelium, contain a clear 

 alcaline fluid, and open by minute orifices on the surface. In the lower 

 half of the cervix the mucous membrane is beset with vascular papilte. 

 The epithelium of the cervix as a whole is cylindrical and ciliated : 

 towards tho os externum this passes into transitional and flat epithe- 

 lium. Besides the follicular glands now mentioned, there are also the 

 so-called ovula Nolothi, a set of clear or yellowish vesicles of variable 

 size, but visible to the naked eye, embedded in the folds of the mem- 

 brane, and extending down to the os externum. These may arise from 

 closed and distended follicles ; but their exact nature is still doubtful. 



During pregnancy the mucous glands of the cervix secrete a consider- 

 able quantity of tenaceous mucus, which effectually closes the passage, 

 downwards from the uterine cavity. 



The mucous membrane of the triangular cavitif of the t)odij is smooth, 

 and in the unimpregnated state entirely devoid of ridges, and is of a 

 peculiar soft or delicate spougy consistence, and of a dull, reddisli. 

 colour. With a magnifying lens of an inch focus its surface is seen to 

 be covered with a great many closely set small spots, in which may be 

 detected the orifices of the utricular glands. This mucous membrane 

 appears to be without any supporting connective tissue, and its thick- 

 ness is made up mainly of its proper glands, between which is a some- 

 what confused mass of small nuclei, cells of various form and size,, 



VOT,. II. ]I ;i 



