You are called to assess the perineal tear after a difficult labour. On examination the tear involves the perineal muscles but sparing the external and internal anal sphincters. You would classify the tear as which of the following?

1st degree perineal tears are superficial and doesn't involve the muscles. 2nd degree perineal tear involves the perineal muscles but doesn't involve anal sphincters. In 3rd degree perineal tears the sphincters are also involved. When rectal mucosa is also involved its called a 4th degree perineal tear. Ref: Oxford Handbook of Clinical Specialities, 8th Edition, Page 92.