A new concept of the anatomy of the anal sphincter mechanism and the physiology of defecation. IV. Anatomy of the perianal spaces.
A study of the perianal spaces was performed in 22 cadaveric specimens using dissection and microscopic examination. Six spaces could be recognized: subcutaneous, central, intersphincteric, ischiorectal, pelvirectal, and submucous. A mention of the central and intersphincteric spaces could not be traced in the literature. The anatomic relations and communications of the perianal spaces are discussed. The central space occupies the area between the longitudinal muscle termination and the base loop of the external anal sphincter. It is the headquarters of all of the perianal spaces as it communicates with all of them. The intersphincteric spaces lie along the longitudinal anal muscle. They constitute the main tracks for extension of pus along the anal canal. The ischiorectal space communicates directly with main tracks for extension of pus along the anal canal. The ischiorectal space communicates directly with the subcutaneous space without the intervention of a septum. The pelvirectal space communicates with the perianal skin through the intersphincteric spaces. The author failed to demonstrate the musculus submucous space; in its place a collagenous internal anal septum could be identified. Furthermore, no trace for the suspensory ligament of Parks was detected; the lower anal lining was found to be pulled by the medial central septum derived from the central tendon.
D000293:Adolescent; D000328:Adult; D001003:Anal Canal / Q000033:anatomy & histology* / Q000502:physiology; D003672:Defecation; D005260:Female; D006801:Humans; D007231:Infant, Newborn; D008297:Male; D009132:Muscles / Q000033:anatomy & histology* / Q000502:physiology