Piles or hemorrhoids are swollen rectal vein or hemorrhoidal venous plexus present in rectum like pads or cushion. The anal canal is a short, muscular tube at the last part of the large intestine and is about 4 cm long. At the lower end of the anal canal it opens outside by anal orifice. There is a network of small veins (blood vessels) in rectum within the lining of the anal canal. Piles can develop when the rectal veins get swelled up. The engorged blood vessels sometimes get ruptured at more straining result from constipation, hard dry stool, pregnancy condition etc.