Rectal sensation is required to detect the presence, nature and amount of rectal contents. There is a range of risk factors and causes associated with rectal prolapse, although doctors do not fully understand why some people get it. Double your portion size. Flatus incontinence may be the first sign of FI. Views Read Edit View history. Endoanal ultrasound, which some consider to be the gold standard for detection of anal canal lesions, [22] evaluates the structure of the anal sphincters, and may detect occult sphincter tears that otherwise would go unseen.