A generally accepted explanation for the etiology of anorectal abscess and fistula-in-ano is that the abscess results from obstruction of an anal gland and the fistula is due to chronic infection and epithelialization of the abscess drainage tract. Anorectal abscesses are defined by the anatomic space in which they develop and are more common in the perianal and ischiorectal spaces and less common in the intersphincteric, supralevator,and submucosal locations.