What causes anal fissures?

Trauma.: Anal fissures are usually the result of trauma to the inner mucosal lining of the anus. Most commonly this occurs when the anal canal stretches after a hard, dry bowel movement. Other causes of a fissure include diarrhea or inflammatory conditions of the anal area. Less commonly, an anal fissure may result from foreign body insertion or anal intercourse.

Tearing anal lining: Many things can cause an anal fissure but in general it is caused by straining. The straining causes the anus to evert out and the lining tissue tears. The tear leads to bright red blood. The tear exposes the internal anal muscle which reacts by going into spasm which causes the pain which can be severe. So anything that causes us to bear down and strain such as constipation, lifting, etc.

Anal fissure: Anal fissure may also be classed as: Primary: no apparent cause. Secondary: due to an underlying condition. For example: Constipation - a hard stool tears the anal mucosa as it is passed. Inflammatory bowel disease - ulceration as part of the inflammatory process. Sexually transmitted infection. Rectal malignancy.