ABSTRACT
Fistula-in-ano and anorectal abscesses share a common cause and differ only with respect to timing. The abscess represents the acute phase, whereas the fistula represents the chronic phase.
ANORECTAL ABSCESS
Anatomy
Successful treatment of fistula-in-ano and abscesses requires an in-depth understanding of anorectal anatomy. Essential is an understanding of the existence of potential anorectal spaces [1,2] (Figure 1). The perianal space is in the area of the anal verge. It becomes continuous with the ischiorectal fat laterally while it extends into the lower portion of the anal canal medially. It is continuous with the intersphincteric space. The ischiorectal space extends from the levator ani to the perineum. Anteriorly, it is bounded by the transverse perineal muscles; the lower border of the gluteus maximus and the sacrotuberous ligament form its
346 Beck and Vasilevsky
A
B
FIGURE 1 Anorectal spaces: (A) coronal section; (B) sagittal section.
