Grade 4 tear from Abbott et al. BMJ 2010;341:c3414. Grade 4 tear from Abbott et al. BMJ 2010;341:c3414.

Grade                           Damage


Grade I                                      Only skin/vagina’s mucous membrane is damaged
Grade II                                     Deeper damage in the vagina and/or perineum

Grade IIIa                                 Less than 50% of the outer sphincter damaged
Grade IIIb                                 More than 50% of the outer sphincter damaged
Grade IIIc                                 Both outer and inner sphincter damaged

Grade IV                                  Outer and inner sphincter damaged and also
                                                  rectum’s mucous membrane damaged
                                                

 

Grade III a, b and c as well as grade IV are so called anal sphincter tears.