A "fissure" is a tear or a cut in the lining of the skin. An "anal fissure" is nothing but a tear in the lining of the skin around the anus, which is different from Piles or Fistula. It is non life-threatening and treatable. It is quite common among adults and young children (ages 0-5). With adults, this condition is easily preventable by following basic instructions and advices.