Anorectal Anatomy

  • Choon Sik Chung


An anatomical definition of the anal canal is from the dentate line to the anal verge. The dentate line is located approximately 2 cm proximal from the anal verge and about the middle of the internal sphincter. The pelvic muscles can be classified into three categories: (1) muscles attached along the pelvic bones, (2) pelvic floor muscles, and (3) anal sphincter muscles. The fascia structure is an anatomically important surgical index as it is a surgical resection plane and also a pathway of disease such as an abscess. Anorectal spaces including the perianal, intersphincteric, ischiorectal, postanal, and retrorectal space are comprised of the levator and anal sphincter muscles. The rectum is supplied by the median sacral artery and upper, middle, and lower rectal artery. The venous drainage of the rectum is to the inferior mesenteric vein into the portal system. Lymphatic drainage of the rectum is parallel to the running of arterial blood.


Anatomy Anal sphincter Anorectal space Perineal body 


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Copyright information

© Springer Nature Singapore Pte Ltd. 2019

Authors and Affiliations

  • Choon Sik Chung
    • 1
  1. 1.Colorectal Division, Department of SurgeryHansol HospitalSeoulSouth Korea

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