**7. Classification**

Anal fissures may be classified as acute or chronic and typical or atypical. Acute fissures cause bright red bleeding with bowel movements and anal pain or spasm that can last for hours after the bowel movement. They have the appearance of a simple tear, superficial or deep in the anoderm. Chronic anal fissures present with induration at the edges, a sentinel pile, visible fibers of the internal anal sphincter, chronic granulation tissue in the base of the fissure and a hypertrophied anal papilla. They are acute fissures that fail to heal following 6 to 8 weeks of intensive treatment. Typical fissures are usually in the posterior or anterior midline, and are not associated with other diseases. Atypical fissures can occur anywhere in the anal canal, and tend to be associated with other diseases.
