<prompt> Episiotomy incision was extended posteriorly beyond perineal body injuring the structure immediately posterior to it. Which structure has been injuredExternal anal sphincterIschiocavernosusBulbospongiosusUrethral sphincter  <response>: Ext. anal sphincteris present just posterior to perineal body. Therefore, Ext. anal sphincter can be injured when episiotomy incision given posteriorly beyond perineal body. 