An unequal layer offibroza tissue, traversed by vessels, and supporting and containing the numerous papillm and mucous crypts of vari ous forms and sizes which characterise the cervical mucous membrane, completes this structure. Tough and coriaceons upon the outer portion, and thinner and more delicate within the canal of the cervix, it forms the chief substance of the mucous membrane, and lies immediately upon the muscular coat, the fibres of which become intermingled with it.
The papilla., or villi, as they' are sometimes termed, of the cervix, exhibit considerable varieties of size and figure, being conical, verrucose, or tuberculated, dentate, clavate, and filitbrm. The clavate papillm are usually found fringing the surface and margins of the thinner phew. The dentate usually form a border to those which are a little more fleshy, and are commonly seen at the margins of the lateral and upper mucous folds. The verru cose papillm are seen in various situations, but are most constantly observed in the sharp lateral furrows which constitute the lines of demarcation between the two cervical walls. The filiform papillm are the finest of all. They' are more slender and pointed than the elevate. They occur under two forms, and in two situations.
One of these forrns is invariably present on the outer or vaginal part of the cervix. The whole of this portion, from the margins of the os outwardly, is covered by numerous short close-set thread-like papillm, invisible to the naked eye, but with the help of a sufficient amplifying power easily distinguished by their white colour, through the somewhat dense layer of pavement epithelium and basement membrane that closely covers and binds them down. Similar papillm clothe the inner sur face of the vagina, and form, with those just described, a continuous layer.
The filiforin papillm constituting the second variety are larger and longer than these, so that they may be discerned by the naked eye. They occur usually at the maroins of the os, and may be traced to a variablebdistance within the canal. But their pre,sence here is uncertain, vihile that of the former variety is constant in the situations indicated. These larger fili form papillm may be sometimes seen to form the terminations of the longitudinal cervical plicm in those cases where parallel folds run down to the very margins of the os uteri.
Here the folds, each ending in a little tuft or tassel, form by their junction a close-set crop of villi, which may merely border one or both lips with a narrow fringe, or form a velvetty patch extending outwardly upon the lips of the cervix and being here uncovered by the ordinary dense epithelial layer of this region, which, as just stated, sometimes, terminates at this spot with an abrupt marg,in, they may present the appearance already described as simulatim, an ulcer.
Regardting the minute structure and composi tion of the papillw, all but the finer kinds may be viewed as consisting of the same elements as the mucous membrane itself', for they appear to be produced by mere notchings or indenta tions, extending more or less deeply into that membrane ; they are, in fact, little more than repetitions of the plicte and sulci upon a smaller scale, with a slight difference of form. They serve to extend the secreting surface, and possibly to expose a larger aggregate superficies of vascular and nervous tissues.
One or more long and slender blood-vessels may usually be traced from the muscular coat running into each papilla. These are suf ficiently conspicuous in thin sections without the aid of injections. By the aid 6f the latter they may be seen to terminate in vascular loops upon the ends of the papillx, just as similar vessels may be observed to form wavy coils upon the crests of the plicx by which the cervix is lined.
The filiform papillx, both larger and smaller, are more finely-constructed than the rest. They often end in a slightly bulbous extremity. Those upon the outer portion of the cervix are usually single, their length being from two to six times that of their breadth. The free uncovered filiform papillm of the cer vical canal and margins of the os are relatively much longer. Tnese latter are commonly branched, and in conformation occasionally resemble the early villi of the chorion. Each villus. whether single or ramified, contains usually a single capillary loop, which returns upon itself, and at the base passes on to an other villus. Covering the capillary loop is a delicate basement membrane, uniting toge ther the clear granule-holding nucleated cells, which constitute the epithelial covering as well as the substance of the villi, and of which a description has been already given.