=Operation.= The same preliminaries are carried out as before. The incision is carried completely round the cervix at its junction with the vagina. The lateral margin of the vulva is then held tense, and an incision is made, beginning at the circumcervical incision running down the lateral vaginal wall, through the margin of the vulva and on to the skin externally, ending at a point midway between the perineum and the ischial tuberosity, _i.e._ about 1-1/2 inches to the side, and in front of the perineum; the incision may be lateral only or bilateral. In sewing up, it is important to reunite the cut edges of the levator ani, or pelvic weakness will result. CHAPTER XV OPERATIONS UPON THE UTERUS PASSAGE OF THE UTERINE SOUND This is an operation which is much less frequently resorted to than formerly, owing partly to the risks of sepsis attending its performance and partly to the greater perfection of the bimanual examination. Passing the uterine sound should always be looked upon as a surgical operation. The facts learnt by the use of the sound are: (1) the length and direction of the uterine cavity; (2) the condition of the endometrium: bleeding as a rule follows withdrawal in fibro-myomata and endometrial disease; (3) whether a fibroid growth is projecting into the uterine cavity, and if so, how much. [Illustration: FIG. 50. THE PASSAGE OF THE UTERINE SOUND. _Introduction of the point into the external os uteri._] [Illustration: FIG. 51. THE PASSAGE OF THE UTERINE SOUND. _Commencement of the tour de maître._] The sound may be passed in the dorsal position (Fig. 61), the cervix being held by a volsella and exposed by means of a posterior speculum, or in the left lateral position, the method usually adopted in the consulting room. In the latter the right index-finger is passed up to the anterior lip of the cervix, the sterilized sound is taken in the left hand with its concavity backwards and its bulbous end is slid gently along the palmar surface of the finger in the vagina until the os uteri externum is reached; through this it should be passed for about a quarter of an inch (Fig. 50). The instrument should now be steadied by the thumb and the two distal joints of the second finger of the right hand, and its subsequent movements controlled by the left (Fig. 51). [Illustration: FIG. 52. THE PASSAGE OF THE UTERINE SOUND. _Completion of the tour de maître._] [Illustration: FIG. 53. THE PASSAGE OF THE UTERINE SOUND. _Entry of the sound into the uterine cavity._]