What is the Goodsall rule
- The Goodsall rule helps predict the location of the internal opening of an anal fistula based on the site of its external opening.
- Accurately determining the criminal crypt of fistula origin on the dentate line is important at the time of surgical treatment, generally fistulotomy.
- If the anus is divided into imaginary anterior and posterior halves in the coronal plane, posterior fistulas tend to curve into the posterior midline.
- Anterior fistulas shorter than 3 cm tend to proceed radially to the dentate line, whereas anterior fistulas longer than 3 cm may track back to the posterior midline.
