A third or fourth degree tear is a tear of the vaginal skin and the muscles between the vagina and anus. If the tear extends into the muscle surrounding the anus it is called a third degree tear and this is further categorised according to the depth of the tear. A fourth degree tear is a tear which extends into the inside of the anus. They are also called Obstetric anal sphincter injuries (OASIS).
Physiotherapy following a grade 3 or 4 perineal tear
