The length of the anal canal


The authors measured the length of the surgical anal canal (anorectal ring to anal verge) in 108 men and 103 women; the age ranged from 18 to 90 years (average 59 years). The average length of the surgical anal canal was 4.2 cm (range 3.0–5.3 cm). In men the average length was 4.4 cm (range 3.2–5.3 cm) compared with the average length of 4.0 cm (range 3.0–5.0 cm) in women (P<0.001). The average length of the anatomic anal canal (dentate line to anal verge) was 2.2 cm (range 1.0–3.8 cm). In men, the average length was 2.2 cm (range 1.4–3.8 cm), whereas in women the average length was 2.0 cm (range 1.0–3.2 cm) (P<.01). The length of the anatomic and cnal has no relationship to the length of the surgical anal canal orvice versa (P<0.1). There was no statistically significant difference in the length of the surgical anal canal or the anatomic anal canal in persons below 60 years old versus those above in either sex (P>0.1).

This is a preview of subscription content, log in to check access.


  1. 1.

    Milligan ETC, Morgan CN. Surgical anatomy of the anal canal: with special reference to anorectal fistulae. Lancet 1934;2:1150–56.

    Article  Google Scholar 

  2. 2.

    Goldberg SM, Gordon PH, Nivatvongs S. Essentials of anorectal surgery. Philadelphia: JB Lippincott, 1980;3:21.

    Google Scholar 

  3. 3.

    Goligher JC. Surgery of the anus, rectum, and colon. 4th ed. London: Baillière Tindall, 1980;7:16–17.

    Google Scholar 

Download references

Author information



Corresponding author

Correspondence to Dr. Sasnthat Nivatvongs M.D..

About this article

Cite this article

Nivatvongs, S., Stern, H.S. & Fryd, D.S. The length of the anal canal. Dis Colon Rectum 24, 600–601 (1981).

Download citation

Key words

  • Anal canal
  • Surgical anal canal
  • Anatomic anal canal
  • Anorectal ring