Where are anal fissures most commonly located?

Anal fissures are most commonly found at the midline posterior aspect, often referred to as the 6 o'clock position. The anatomical structure of the anal canal, along with the characteristic vascular supply and muscular control, contributes to the prevalence of fissures in this area. The posterior midline is less vascularized and has a thinner epithelium, which makes it more susceptible to trauma and subsequent fissure formation.

Additionally, fissures at the 6 o'clock position are frequently associated with underlying causes such as constipation and straining, which puts extra pressure on this region during bowel movements, contributing to its vulnerability. While anterior (12 o'clock) and lateral (3 and 9 o'clock) positions can also be sites of fissures, they occur significantly less frequently due to the better blood supply and thickness of tissues in those areas, reducing the likelihood of fissuring.

Therefore, recognizing the typical location of anal fissures is crucial for diagnosing and managing patients effectively. The posterior midline remains the most consistent location for these lesions in clinical practice.