 Perianal abscess, which represents the most common type of anorectal abscesses accounting for about 60% of reported cases, are superficial collections of purulent material just beneath the skin of the anal canal.Ischiorectal abscess is formed when suppuration transverses the external anal sphincter into the ischiorectal space.Intersphincteric abscess results from suppuration contained between the internal and external anal sphincters

Supralevator abscess forms from cephalad extension of the intersphincteric abscess above the levator ani or from caudal extension of a suppurative abdominal process like appendicitis, diverticular or gynaecologic sepsis.