What is the most common type of anal fissure?

In the context of anal fissures, the most common type is the posterior fissure. This type of fissure typically occurs due to trauma to the anal canal, often linked to straining during bowel movements. The anatomy of the anal canal and the distribution of blood supply contribute to this common occurrence.

Posterior fissures are usually located at the 6 o'clock position of the anal canal and are frequently associated with conditions such as constipation or diarrhea, which place excessive strain on this area. Their prevalence can be attributed to the embryological development of the anal canal and the relative tension on the anal sphincters in the posterior region, making it more susceptible to tearing.

On the other hand, intersphincteric fissures, while they can occur, are less common compared to posterior fissures. Lateral fissures and anterior fissures are also rare, with lateral fissures often being associated with underlying conditions like Crohn's disease or other systemic diseases, and anterior fissures being predominantly found in females, linked to anatomical differences.

Understanding these patterns can help healthcare providers in diagnosing and managing anal fissures effectively.