THE TUBES OR OVIDITCTS.
The uterine tubes, Fallopian tubes or oviducts, are two tubes which bring the semen into contact with the ovule, and conduct the ovule into the interior of the womb. (Fig. 44.) They are situated at the sides of the uterus, to the superior angle of which they are attached, and occupy the free edge of the middle wing of the broad ligament.
They are straight near their origin, at the uterus, but at the end they bend and form, with their external half, a curve, the concavity of which .faces backward, inward and downward. They terminate in an enlarge ment, turned towards the ovary.
Their length does not generally exceed 4.6 inches. Their diameter increases from the uterus toward the ovary. Near the uterus it is .15 inches, in its middle about .23 inches, and at the external or abdominal opening it reaches about .31 inches.
Shape.—Fallope compared them to a trumpet. They have, therefore, a tubular part, the body of the tube, and a wide part, the pavilion of the tube.
The body of the tube is continuous at its internal extremity with the superior angle of the uterus. It is in connection with the convolutions of the ilium, with the bladder and the ovary.
The tube opens into the cavity of the uterus by its internal or uterine orifice. This is situated at the bottom of the infundibuke, which form the superior angles of the uterine cavity. Its diameter is .039 inches. The external or abdominal opening is at the top of the funnel-shaped pavilion. Throughout its whole length we find on the walls longitudinal folds which do not disappear on insufflation.
The pavilion, the wide part of the tube, is attached, laterally, to the lateral walls of the cavity, in which it somewhat freely floats. Its diameter is generally from .7 to .78 of an inch. It has an external surface, an in ternal surface, and a circumference.
External Surface.—It is continuous with the body of the tube; is covered by peritoneum, and is smooth and even.
Internal Surface.—This is concave and faces backward, downward, and inward, towards the ovary. The abdominal orifice is situated in its centre.
A number of folds, which are continuations of the longitudinal folds of the body, leave the orifice of the pavilion and radiate towards its circum ference. This circumference is not circular, but is cut into bands, called fringes. One of these, longer than the others, extends to the external extremity of the ovary, and forms the ligament of the tube.
G. Richard notes on the external third of the tube the presence of accessory pavilions, which occur only once in sii. Sappey believes them to be much less frequent.
tube has three coats: an external serous; a middle muscular; and an internal mucous.
The external or peritoneal coat only envelopes three quarters of the cir cumference of the tube. It terminates on the free edge of the fringes, when it reaches the pavilion.
The muscular layer consists of two layers of fibres. An external, com posed of longitudinal fibres, which, according to Sappey, are formed by a prolongation of the fibres of the uterus, but which are, according to Robin, entirely distinct. A deep layer composed of circular fibres, be ginning at the abdominal orifice, where it forms a sort of sphincter, it continues to the uterus where it disappears. The uterine portion of the oviduct is represented only by the mucous coat.
The mucous coat has numerous folds. It is continuous at the internal extremity with the uterine mucosa; at its external extremity it extends to the base of the pavilion, i.e., to the peritoneal envelope. The mucosa of the tube is covered with cylindrical epithelium with vibratile cilia; the peritoneum with pavement epithelium.
The vibratile cilia. point from the ovary towards the uterus. Their func tion is to conduct the ovule to the womb, after it has been seized by the pavilion of the tube.
Vessels and arteries come from the utero-ovarian artery.
The veins terminate in the utero-ovarian vein.
The lymphatics join those of the uterus and ovary and empty into the lumbar glands.
The nerves are very numerous and come from the utero-ovarian plexus.