Haemorrhoids (piles) are enlarged blood vessels that you can get inside or around your anus (the opening of your bottom). It's completely normal to have blood vessels in your anus, as they play an important role in continence. But piles can develop if these blood vessels become enlarged, which can cause symptoms.

Fissures result from the stretching of your anal mucosa beyond its normal capacity. This often happens when stools are hard due to constipation. Once the tear happens, it leads to repeated injury. The exposed internal sphincter muscle beneath the tear goes into spasm. This causes severe pain.

A fistula is an abnormal connection between two body parts, such as an organ or blood vessel and another structure. Fistulas are usually the result of an injury or surgery. Infection or inflammation can also cause a fistula to form.