A small tear in the lining of the anus.
Anal fissure is a small tear in the tissue that lines the anus. It may happen when passing hard or large stools.
It causes pain and bleeding during bowel movements and may cause spasms in the ring of muscle at the end of the anus.
This condition usually heals on its own in 4 to 6 weeks. If it doesn't, treatment or surgery can relieve pain.