account of its containing the apertures of the urethra and vagina. Within this fissure a slightly marked crescentic fold of integument stretching between the hinder parts of the labia majora will be observed. This fold receives the name of the "fourchette" or "frænulum pudendi," It is usually ruptured in first labours.

Between the fourchette and the entrance to the vagina there is a depression which is known as the fossa navicularis.

It may be well for the student to bear in mind that the term "perineum" in the language of the obstetric surgeon is used in a very restricted sense. It is given to the narrow interval which exists between the anus and the fourchette.

They are placed As they proceed and at the same

The Labia Minora or Nymphæ represent the male prepuce. They are two pendulous folds of integument which lie within the labia majora. To display them fully the labia majora must be pulled apart. one on each side of the vaginal orifice. forwards they become more prominent, time converge so as to approximate to each other more closely. Reaching the clitoris, each terminates by splitting into two divisions or folds. The smaller and lower fold is attached to the under surface of the clitoris, and receives the name of frænulum clitoridis. The upper fold arches over the clitoris like a hood, and unites with the corresponding fold of the opposite side to form the præputium clitoridis.

The Clitoris is the homologue of the penis, and, notwithstanding its diminutive proportions, it presents a close resemblance to the male organ both in appearance and structure. It is a minute elongated projection placed below the anterior commissure, and surmounted by a sensitive rounded tubercle called the glans, but it is not traversed by the urethra. The manner in which its prepuce and frænum are formed has already been described. To obtain a proper view of the clitoris the student must lay hold of the glans with the forceps and draw it out from the prepuce.

Vestibule.-The dissector should next take note of a smooth triangular interval which exists between the clitoris and the entrance to the vagina. The term vestibule is given to this area. It is bounded laterally by the nymphæ, and towards its lower part or base is seen the orifice of the urethra.

The triangular outline of the vestibule is only seen when the labia are forcibly drawn apart from each other. In the natural condition of parts the labia are in close apposition, and the vestibule is then a deep recess which represents the bottom of the pudendal cleft, between the clitoris and the vagina.

The Urethral Orifice lies close to the opening of the vagina, about one inch below the clitoris. It is circular in form, and the mucous membrane around it is prominent, pouting and slightly puckered, so that when the tip of the finger is passed over the vestibular area the opening can readily be distinguished by touch.

The Vaginal Orifice, in the virgin, is partially closed by the hymen -a semilunar fold of mucous membrane attached to the posterior aspect and sides of the entrance to the vagina, and presenting a free concave margin towards the pubes. The form of the hymen, however, is very variable. Sometimes it is present in the shape of a septum attached around the entire circumference of the vaginal entrance, but pierced in the centre by a circular opening or a vertical slit; again, it may be cribriform or fringed along its free margin. Lastly, it may constitute a complete septum across the opening of the vaginal canal. In this case awkward results ensue from the retention of the menstrual fluid. After it has been ruptured its position is marked by certain rounded elevations which have received the name of carunculæ myrtiformes.

Passage of Catheter and Examination of Os Uteri. -The dissector should now practise the passing of the female catheter, and afterwards introduce a speculum into the vagina, so as to obtain a view of the os uteri.

The difficulty in passing the catheter arises from the fact

that the operation must be conducted without any exposure of the person. Place the forefinger of the left hand in the orifice of the vagina, with its palmar surface directed upwards towards the pubes. If the instrument be now passed along this finger, and the point raised slightly when it reaches the entrance to the vagina, a little manipulation will cause it to enter the urethra.

When the speculum is introduced into the vagina, the points to be noted in connection with the os uteri are:(1) the small size of the opening; (2) the two rounded and thick lips which bound this aperture. In the virgin the opening is circular, but in women who have borne children it is somewhat transverse and often scarred. Note further that the anterior lip is the thicker and shorter of the two, whilst the posterior lip is the longer.

Reflection of Skin. The rectum should be moderately filled with tow, and the vulva and anal orifice stitched up.—Incisions—(1) A transverse incision should, in the first place, be carried from one ischial tuberosity to the other, in front of the anus; (2) The urogenital fissure and the orifice of the anus should next be closely encircled by incisions, and these joined by a cut along the middle line. (3) Lastly, carry an incision forwards from the second or third piece of the coccyx along the middle line to the cut which surrounds the anus.

Four flaps are thus marked out; the two anterior may be thrown forwards and outwards, and the two posterior backwards and outwards.

Superficial Fascia.-The superficial fascia of the perineum is now laid bare. In the rectal triangle it agrees in every particular with the same portion of fascia in the male. In the anterior or urogenital triangle, however, owing to the difference in the external organs of generation, there is a slight modification. It presents the same two layers. In the superficial fatty layer, where it covers the labia majora, there are dartos fibres similar to those in the scrotum of the male. The deeper layer has the same attachments as in the male, viz., to the anterior lips of the pubic arch, and to the base of the triangular ligament; but it is not so membranaceous, and consequently does not form so distinct a stratum. The two fascial pouches are

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also present in the female, and are sometimes spoken of as the vulvo-scrotal sacs. Their separation along the middle line is not due to the interposition of a median septum, as in the male, but to the presence of the urogenital fissure.

RECTAL TRIANGLE.

Nothing need be added to what has already been written regarding this portion of the perineal space in the male. In both sexes the steps of the dissection and the parts found are precisely the same (vide p. 338).

UROGENITAL TRIANGLE.

Superficial Perineal Vessels and Nerves.-Under this heading we include two arteries and three nerves, viz.:—

Arteries. {

Nerves.

{

The superficial perineal artery.
The transverse perineal artery.

The posterior superficial perineal nerve.
The anterior superficial perineal nerve.
The long pudendal nerve.

They have precisely the same disposition as the corresponding vessels and nerves in the male, with this exception, that they are somewhat smaller, and are distributed to the labium majus, instead of to the scrotum. For a detailed description of these structures, the student may refer to p. 347.

Dissection.-The superficial perineal vessels and nerves should now be divided and thrown backwards, and the superficial perineal muscles cleaned. These are three in number, viz., the transversus perinei, the erector clitoridis, and the sphincter vaginæ. The two first have a similar position to the corresponding muscles in the male; the sphincter vaginæ lies upon the side of the vagina close to its orifice. To obtain a good view of these muscles the superficial fascia and the labia should be dissected away.

In cleaning the muscles the dissector should look for the small nervous twigs which are given to each by the perineal division of the internal pudic nerve.