What is the difference between anterior/posterior anal fissure and lateral anal fissure? What is considered abnormal in terms of anal fissure location
Posterior / anterior. Most "normally located" fissures are due to passage of hard, dry stools or explosive diarrrhea. These are almost exclusively posterior in men but can be anterior in up to 10% of women. These respond well to lateral internal sphincterotomy. Secondary anal fissures are associated with crohn disease, leukemia and certain other neutropenic blood conditions. Surgery should be avoided.