Degree | Definition |
---|---|
First | Injury to vaginal mucosa or perineal skin only |
Second | Injury to vaginal mucosa or perineal skin and superficial perineal muscles |
Third | Injury to anal sphincter muscles and subdivided into |
3A | < 50% of external anal sphincter muscles is injured |
3B | > 50% of external anal sphincter muscle is injured |
3C | External and internal anal sphincter muscles are injured |
Fourth | Injury involving external and internal anal sphincter muscles and anal epithelium |