| Category | Piles |
Piles are blood vessels located in the smooth muscles of the walls of the rectum and anus. They are an integral part of the anatomy and are located at the junction where the small arteries merge with the veins. They are cushioned by smooth muscle and connective tissue and classified according to their position relative to the pectinate line, the point of separation between the upper 2/3 and lower 1/3 of the anus. This is an important anatomical distinction because of the types of cells that line the hemorrhoids and the nerves that provide sensation.
