\regaling, Nortwich, Sue, Hunter, Meckel, Calza, Mme. Boivin, Deville, Pappenheim, Rouget and Sappey, studied the structure of the uterus, and Chenantais and 116lie (of Nantes) have given a classical description of it, from which we take what follows.
There are two sets of fibres in the uterus: the intrinsic and the extrin sic. • A. Extrinsic proves that in animals the uterus is cov ered with a muscular envelope covering the anterior and posterior sur face of the organ, doubling over the broad ligaments throughout their entire extent, and attached to the pelvic walls, after having given off fibres to the round ligaments, the ligaments of the ovary, to the ovary and to the Fallopian tubes. These he calls extrinsic fibres. (See Fig. 41). In woman there is but a single group of fibres, which do not form a true layer, but only a kind of mesh-work composed of large links, whose fibres spring from the round ligament, ligament of the ovary and tube, cross over the front of the organ, and go to strengthen the broad liga ments of the opposite side. These fibres are best marked posteriorly, and form the " posterior round ligament." A few of those fibres are found in the utero-vesical folds and utero-sacral ligaments. Other fibres are lost in the ovary and Fallopian tube.
B. Intrinsic divides these into three layers.
A. External consists of two layers, one of which 'Ube calls the ansiform or arciform fascia, already described by Sue, Calza, Boivin, Deville, Dubois and Pajot. It consists of longitudinal fibres, which. pass from the posterior surface of the uterus over the fundus to cover also the anterior surface. Behind, it begins on a level with the union of the cervix and body of the uterus, and is made up of fibres that, at first, were transverse but later are longitudinal. It increases as it rises from the addition of new elements, At the fundus, the lateral fibres run out toward the tubes and broad ligaments, mingling with the extrinsic fibres. The central fibres alone, then, cover the fundus. This layer was described by Devine, who claimed that these fibres formed a Z, running from left to right; liaie denies such interlacing, or at least claims that only a few fibres so cross over.
The second layer of the superficial fibres is transverse, some forming the ansiform layer, while the greater number pass below to run out on to the broad ligaments, the ligaments of the ovary, the round ligament and the Fallopian tube. At the angles of the uterus they curve in an arched form.
The borders of the uterus are made up of transverse fibres, running from one face to the other, now horizontal, now arciform, and now circu lar. The deep become superficial and vice versa. They are disso ciated by vessels that run in them, and then penetrate the sides of the uterus. Part of these fibres go to the broad ligament, ovary and tube, but the greater number pass to the sides of the uterus.
In the Cervix. —Hypertrophy of the muscle-fibres is, here, less than in the body. There is no ansiform layer, the fibres running from the sides of the uterus to the median line, and interlace among themselves. At the sides of the organ, they run from one face to another. The most superficial fibres run to the utero-vesical folds in front, the utero•sacral behind, and the vagina below.
b. Middle Layer. (Fig. 86). —This is indeterminate. It is made up of muscle-fibres running in every direction and interlacing; they form rings about the veins—indeed, sheaths for each one of the uterine veins. The arteries are likewise covered by these fibres, but are also provided with a cellular sheath wanting in the veins, so that the latter adhere by their internal tunic to the muscular tissue, whereas the arteries glide within these sheaths.
c. Internal Layer. (Fig. 87).—Posteriorly, this is formed by a tri layer extending from one tube to the other, and down to the cervix. Like the ansiform layer of 116lie, it consists of transverse fibres, which interlace with those of the opposite side. The upper end of this layer terminates in the orifices of the tubes.
On the anterior surface, the triangular layer is less marked. At the side of these triangular masses, transverse fibres pass from one surface of the uterus to the other, forming arches, which become circles around the orifices of the tubes: the orbicular muscles.