What does Goodsall's rule apply to?

Goodsall's rule applies specifically to the classification and surgical approach to anal fistulas based on their anatomical location relative to the anal verge. This rule posits that fistulas presenting less than 3 centimeters from the anal verge typically have a direct connection to the anal canal, while those that are more than 3 centimeters away, particularly those oriented anteriorly, are likely to follow a path toward the posterior midline, connecting to the anus.

In the context of this question, the focus on fistulas less than 3 cm from the anal verge is crucial because such fistulas tend to have a simpler pathway that is easier to understand and manage during surgical treatment. Fistulas in this category have a higher likelihood of being classified as intersphincteric or low transsphincteric, aligning with the clinical significance of Goodsall's observation.

In contrast, fistulas more than 5 cm from the anal verge or anal fissures do not directly relate to the application of Goodsall's rule, as the principles governing their treatment may differ significantly. Similarly, rectal prolapse is a condition that concerns the descent of the rectum rather than the pathways of anal fistulas, further distancing it from the parameters of Goodsall's rule