Definition and symptoms of anal fissure
An anal fissure is a split in the skin of the anal canal, often precipitated by passage of a hard stool. Acute fissures present with anal pain that worsens with defecation, and a small volume of bright red blood from the rectumStewart, 2017.
Most anal fissures (90%) are posteriorStewart, 2017; the remainder are anterior (5%), or in other positions (5%). If an anal fissure is in the lateral position or is chronic (lasting more than 8 to 12 weeks), an underlying cause (eg Crohn disease, infection, anal carcinoma) must be excluded.