<prompt> During the delivery, it is necessary to do an episiotomy. The tear extends through sphincter of the rectum, but the rectal mucosa is intact. How would you classify this type of perineal tear? NOT RELATED-GYNIst Degree2nd degree3rd degree4th degree  <response>: A first degree tear involves the vaginal mucosa or perineal skin, but not the underlying tissue. In a second degree episiotomy, the underlying subcutaneous tissue is also involved, but not the rectal sphincter or rectal mucosa. In a third degree tear, the rectal sphincter is affected. A fouh-degree episiotomy involves a tear that extends into the rectal mucosa. 