An anal fissure is a small crack or tears in the thin, moist tissue lining the anus. The anus is a highly sensitive part of the body, therefore, a small tear in this region can result in severe pain.
It is the most common cause of rectal bleeding in infants and young children. It can be acute or chronic, if the anal fissure lasts less than 6 weeks it is called acute and if it lasts longer than 6 weeks it is known as chronic anal fissure.
It is caused by trauma to the lining of the anus from a stretching of the anal canal. The cause of the trauma may include