The anal canal is a short tube surrounded by muscle at the end of your rectum. a gloved, lubricated finger into the anus and rectum to feel for lumps or other. Jun 15, - The most frequent causes of rectal bleeding are hemorrhoids, fissures and polyps. should be palpated in addition to digital assessment of the anal canal. . Anal or perineal “lumps” may be due to a wide range of conditions.