Anal Ultrasound is a study of the anal sphincter anatomy. It is performed with ultrasound waves and is painless. The test will be performed on an outpatient basis in one of the clinics at Cedars Sinai. The test will be administered by a colon & rectal surgeon. An ultrasound probe will be placed into the anal canal and ultrasound waves will be used to determine the anal sphincter anatomy- specifically if the muscles of the anal sphincter muscle complex have been damaged. Another reason for an Anal Ultrasound is to evaluate a complex perirectal fistula.