THE FEMALE GENITAL ORGANS. 879 



vagina by a narrow canal that passes through the posterior constriction of 

 the uterus (cervix), and which is, in Human anatomy, named tlie cavity (or 

 canal) of the cervix (os uteri, os externum, os tricce). In all the domesticated 

 animals, except the Eabbit, the uterine canal is prolonged to the bottom of 

 the vagina, in something the same fashion as a tap is into the interior of a 

 barrel ; and in this way it always forms a very marked projection in the vaginal 

 cavity. Around this projection, the utero-vaginal mucous membrane is 

 raised in transverse folds disposed in a circular manner, which give it the 

 appearance of a radiated flower ; in Veterinary anatomy, this projection of 

 the cervix is consequently named the " expanded flower " fleur epanouie ; it 

 is the tench's nose of the Human being. 



STRUCTURE. The walls of the uterus are composed of three membranes : 

 an external, serous; a middle, muscular; and an internal, mucous; with 

 vessels and nerves. 



The serous tunic envelops all the organ ; it is an expansion of the 

 broad ligaments, which are prolonged backwards on the posterior extremity 

 of the vagina, and are afterwards doubled in a circular fashion around that 

 canal, to pass over either the rectum, the bladder, or the lateral walls of the 

 pelvis. Between the two cornua this membrane forms a particular frsBnum, 

 which is but slightly developed in Solipeds. 



The muscular layer comprises longitudinal (superficial), and circular 

 (deep) fibres, analogous to those of the small intestine. Near the insertion 

 of the broad ligaments, they give off a series of fasciculi which are pro- 

 longed between the two layers of these ligaments. These are not the only 

 muscular fibres met with in the ligaments, however ; for Rouget has found 

 others throughout their whole extent, but particularly in the vicinity of the 

 ovaries. 1 (Around the cervix uteri, the circular fibres are most dense and 

 numerous.) 



In the pregnant animal, the number of fibres composing this layer is 

 much more considerable than in ordinary circumstances ; and this increase 

 has for its object to permit the dilatation of the uterus, without allowing 

 its parietes to become too attenuated ; they do become more or less thin, 

 notwithstanding, according to the species. It has also been remarked that, 

 during pregnancy, the muscular fibres present a manifest striation. (The 

 elements of these fibres are short fusiform cells with long oval nuclei, mixed 

 with a large quantity of immature nucleated areolar tissue.) 



The mucous membrane is thin, delicate, and raised into folds. It is 

 covered by ciliated epithelium, which becomes cylindrical in the canal of 

 the cervix, and pavemental around the os uteri. (The cilia vibrate towards 

 the fundus of the organ. The membrane is closely connected with the 

 muscular tunic, and is composed of immature nucleated areolar tissue 

 without elastic fibres.) The uterine mucous membrane is destitute of 

 papillae (except at the cervix, where, according to Leyh, there are many 

 highly vascular papillae) ; but it lodges numerous simple or ramified glands, 

 which are straight or slightly flexuous at their extremities. At the cervix, 

 these glands enlarge at the bottom, and assume something of the appearance 

 of acinous glands. 



(These mucous glands are designated simple and cylindrical. The first 

 are most numerous towards the cervix ; some, here and there, with their 

 orifices closed, are enlarged, and form small vesicular tumours, the ovula 

 Nabothi ; they secrete the peculiar transparent mucus found here. The 



1 Unstriped contractile fibres are also found, in the male, along the spermatic cord, 

 beneath the visceral layer of the tunica vaginalis. 



