Anal fissures can be divided into primary and secondary anal fissures, based on etiology; posterior and anterior anal fissures based on location; and acute and chronic anal fissures based on the duration of symptoms.
Anal fissure classification
Anal fistula classification
Anal fissure laboratory findings
Constipation classification
Anal fissure epidemiology and demographics
Rectal prolapse classification
Anal fissure physical examination
Urethritis classification