Please note that the content of this book primarily consists of articles available from Wikipedia or other free sources online. Hemorrhoids (US English) or haemorrhoids (Commonwealth English), also known as piles and "Tum- Bum", are part of the normal human anatomy of the anal canal. They become pathological when swollen or inflamed. In their physiological state they act as cushions composed of arterio-venous channels and connective tissue that aid the passage of stool. The symptoms of pathological hemorrhoids depend on the type present. Internal hemorrhoids usually present with painless rectal bleeding while external hemorrhoids present with pain in the area of the anus.