The anus is the opening at the end of the rectum through which a bowel movement passes.
Hemorrhoids are one of the most common problems of the lower digestive tract.
Internal hemorrhoids are painless but they sometimes cause a lot of bleeding. The veins may then become irritated and painful. External hemorrhoids can be seen or felt easily around the anal opening. When the swollen veins are scratched or broken by straining or rubbing, they bleed. Veins in the rectum and around the anus tend to expand under pressure.