• Marc A. SingerEmail author


  • Hemorrhoids are normal components of anorectal anatomy.

  • Hemorrhoids are vascular cushions in the submucosal space of the anal canal.

  • Hemorrhoids are classically described as occurring in the left lateral, right anterior, and right posterior position. However, this finding was identified in less 20 % of cadavers.

  • They are composed of blood vessels, connective tissue, and smooth muscles.

  • The smooth muscle is known as Treitz’s muscle and originates from conjoined longitudinal muscle and internal sphincter.

  • Histologically, hemorrhoids lack a muscular wall and are therefore sinusoids (not veins or arteries).

  • Blood inflow to hemorrhoids is from the superior hemorrhoidal artery with some contribution from middle hemorrhoidal artery, and most distally from inferior hemorrhoidal artery. pH analysis of hemorrhoidal bleeding confirms that it is arterial blood.


Anal Canal Dentate Line Internal Hemorrhoid Rubber Band Ligation Calcium Dobesilate 
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Copyright information

© Springer Science+Business Media New York 2014

Authors and Affiliations

  1. 1.Section of Colon and Rectal Surgery, Department of SurgeryNorthShore University Health SystemEvanstonUSA

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