In the case of the uterus unicornis, notwith standing the imperfection of one uterine half, both ovaries may be found alike developed.
The type of this condition of uterus exists as a normal formation in the class ayes, where one side only of the generative apparatus proceeds in its growth, and the other remains undeveloped from an early period of fcetal life.* Group III. If, instead of an unsymmetrical growth of the two uterine cornua, such as occurs in the last example, both sides are alike developed, yet without any, or with only an imperfect, junction of their lateral borders there is produced a uterus bieornis, falsely termed a double uterus (uterus du plex). Here however there is no evidence of plurality, or true duplicity of the uterus, but only a deficiency of' that union of the two separately formed halves by whose subsequent conjunction the organ is normally constituted.
This conjunction should naturally com mence from the level of the point of attach ment of the round ligaments, and the varia tions in the degree of malformation will be according to the height at which the union of the uterine halves stops short of that point.
The highest degree of malformation in this group, or the greatest departure from the normal form, is that in which the two uterine halves do not coalesce at all, but remain com pletely divided in their whole extent. This happens very rarely, and is co-existent with other malformations, such as fissure of the abdominal and pelvic walls. The division is here so complete that certain of the pelvic or abdoininal viscera may occupy the space be tween the two uterine halves.
In the next degree of this kind of deformity a horizontal comtnissure occupies the angle in which the two uterine halves meet, and serves to unite them together (fig. 461.). The horizontal commissure is composed, like the eornua, of uterine tissue, and represents the fundus uteri. According to the height at -which it is placed, the external form of the uterus approaches or recedes from the normal type. ltokitansky* has pointed out how the situation of this commissure affects the angle in which the two cornua meet, and conse quently the relative mutual position of the two uterine halves. The nearer the point of co alescence of the two halves approaches to the external orifice, the rnore obtuse will be the angle at which their junction takes place, and the more extensive will be the fissure ( fig. 461.). On the other hand the higher the point of union, the more acute will be their angle.
This becomes obvious in the lesser degrees of deformity represented in figs.462. and 463. In fig. 462., although the comrnissure is placed at a higher point than infig. 461., so as to be much further removed from the external os, there is still a considerable separation of the two cornua, and their direction is still mainly horizontal ; but infig. 463., where a more per
fect coalescence of the two halves has taken to the extremity of the vagina, dividing the latter, fig. 461., together with the hymen in the virgin state, so that there are two com plete canals leading to corresponding uterine halves.
Group IV. In this group the external form of the uterus differs but little from the normal character. The breadth of the organ, especially between the points of entrance of the Fallopian tubes, is usually greater, and the fundus, though arched, is more shallow than usual. Here also a slight notch, extending into a shallow furrow, running along the posterior uterine wall, may indicate the seat of that in ternal vertical septum which more or less completely divides the uterine cavity into two halves, and constitutes the uterus bilocularis ( fig. 464.). i place, and, consequently, where the com missure approaches nearer to the points of attachment of the Fallopian tubes and round ligaments, the angle has become so much smaller, that the two halves begin to lie nearly parallel with one another, and the horns, or ununited portions, exhibit only a slight di vergence.
In this, as well as in the following group of malformations, there often proceeds from the commissure an internal septum which descends to a variable depth, and exercises a corresi ond ing influence upon the separation of the two halves. In cases where the conimissure representing the fundus lies very low, there may be no septum, and a single cervix con ducts into two uterine halves which lie right and left of it. In cases where the fundus is higher, if the septum extends downwards only in a slight degree, as in figs. 462. and 464., the cervix is still common to both sides of the uterus. Where the septum begins to divide the cervix, as infig. 463., the separation of the two uterine halves is more complete, but there is still a common os externurn, leading to the two canals. The highest de gree of division, and consequently lowest type of structure, is that in which the septum ex tends not only through the cervix, but even The extent of this septum, and conse quently- the more or less perfect formation of two separate loculi, exhibits the same varieties as in the former group. The par tition may stop short at the cervix, or ex tend in rare cases completely through that canal, and even divide the vagina. Where the septum is rudimental, and extends only to the cervix, the lower free border is usually thin and falciform (fig. 463.), having its concavity directed forwards, the lower extremity being that which is connected with the posterior uterine wail.