Which anatomy is relevant to proctitis and anusitis?

Updated: Mar 27, 2020
  • Author: David E Stein, MD; Chief Editor: John Geibel, MD, MSc, DSc, AGAF  more...
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Answer

It is important to recognize that most inflammatory processes of the rectum also involve the adjacent colon and the anus. Controversy remains regarding the anatomy of the rectum and the anus. Some authorities say that the rectum starts at the level of the third sacral vertebra, whereas others consider the start of the rectum to be at the sacral promontory.

Where the rectum ends also is debated. Some say that it ends when it passes through the levator ani muscles, but most agree that the rectum transitions to the anus where the epithelial cells change from columnar cells to squamous cells.

The World Health Organization (WHO) and the American Joint Cancer Committee define the anal canal as the distal portion of the gastrointestinal (GI) tract that corresponds to the internal anal sphincter.

In proctitis and anusitis, the anatomy does not change therapy, because a significant overlap between anorectal inflammation and rectosigmoid inflammation exists.


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