The scars upon the mucous membrane and on the skin in time become faint, with difficulty perceptible. By elevating the anterior vaginal wall and closely inspecting the posterior wall immediately within the ostium vaginæ we may detect a fine irregular white line running in the direction of the vaginal sulcus and dividing the normal transverse ridges and furrows of the vaginal mucous membrane. This is the only sign of former injury to the vaginal mucous membrane. The injury to the underlying structures--the supporting structures of the perineum, the muscles and the fascia--is indicated by certain characteristic and unmistakable signs. These signs are best recognized after a careful study of the normal uninjured perineum. If an uninjured woman be placed in the lithotomy position and the perineal region be carefully examined, we observe the following points: The anus is not prominent: it is drawn upward and forward; the anal cleft is deep. The perineum, or the surface between the anus and the fourchette, is shallow; the distance from the anus to a fixed point like the external meatus is relatively short: this surface is more or less convex, showing muscular tonicity. If the labia are separated, it will be observed that the anterior and posterior vaginal walls are in close apposition. If the woman is made to strain or to bear down, the vaginal walls appear to come into close contact; the perineum is pushed directly downward, and becomes more prominent under the increased intra-abdominal pressure, but there is no tendency to eversion or rolling out of the vaginal walls. If the vulva is pricked with a needle, reflex muscular action is immediately observed: the anus is drawn still more upward and forward; the perineum is shortened; the ostium vaginæ is closed more firmly by the drawing forward of the posterior margin of the opening. The test shows that the muscles supporting the perineum are intact. If the finger be introduced into the vagina and be pressed backward and outward in either vaginal sulcus, resisting structures are felt. There seems to be a band, perhaps half an inch in breadth, immediately within the ostium vaginæ, that holds forward the perineum and the posterior vaginal wall and resists the pressure of the finger. Compare these characteristic features of the uninjured perineum with what we observe in a woman in whom there has been an untreated laceration of the perineum in the vaginal sulci. Here the supporting structures of the perineum have been destroyed. [Illustration: FIG. 44.--Diagram showing the sling of muscle and fascia supporting the perineum and the posterior vaginal wall. In A the parts are intact; in B there has been a laceration in the left vaginal sulcus; in C there has been a laceration in both sulci; a suture has been introduced on the right side.]