<prompt> Rectal incontinence is due to involvement of :a External anal sphincterb Internal anal sphincterc Ischiococcygeusd Pubococcygeusacdbcdabcabd  <response>: Rectal continence depends solely on the anorectal ring and any damage to this ring results in rectal incontinence.The anorectal ring is a muscular ring present at the anorectal junction, and formed by the fusion of -Puborectalis a part of pubococcygeus which in turn is a part of levator aniDeep external anal sphincterInternal anal sphincterThe puborectalis muscle appears to be the most important muscle for maintaining fecal continence. 