If the laceration extends up the posterior vaginal wall, two sets of sutures must be introduced--one on the vaginal aspect of the tear, and one on the skin aspect (Fig. 35). [Illustration: FIG. 35.--Recent slight median laceration of the perineum extending up the posterior vaginal wall: sutures introduced on the vaginal and cutaneous aspects.] The secondary operation of perineorrhaphy is not indicated in slight median lacerations of the perineum that may have been neglected at the time of labor, as the integrity of the pelvic floor is practically unaffected by them. =Median Tear involving the Sphincter Ani.=--In this form of injury the laceration takes place in the median line and extends backward through the sphincter ani muscle, and perhaps upward for one or more inches through the recto-vaginal septum. Permanent incontinence of feces results. Though this is a most extensive injury attended by most unpleasant results, yet it will be seen that none of the supporting structures (the fascia and the muscles) that support the pelvic floor are injured by it. The perineum is split in the middle, but the muscles attached to it, being uninjured, are still able to draw the two halves of the perineum forward, thus supporting the posterior vaginal wall and keeping the vagina closed. There is but very little tendency to separation of the two parts of the split perineum by lateral traction, the only muscle that acts at all in this direction being the feeble transverse perineal muscle. Therefore, though there is loss of power of the sphincter ani muscle, yet in this injury the woman may not suffer any of the consequences of loss of power in the support of the pelvic floor, such as vaginal and uterine prolapse. After laceration of the perineum through the sphincter ani the divided muscle retracts so that it embraces only the posterior margin of the anus. If the injury be not repaired immediately, retraction and atrophy progress, so that in time the sphincter muscle, lying posterior to the anal opening, may be but half an inch in length and of very much less than its normal thickness. Cicatrization takes place, and the parts present the appearance shown in Fig. 37. Notwithstanding the atrophy and retraction of the muscle, continence may be re-established by operation, though many years may have elapsed since the receipt of the injury. Notwithstanding the very obvious reasons for the performance of the immediate operation for the relief of this condition, it is yet very often neglected, and the gynecologist is called upon to repair the injury many years after its occurrence.