Rapid Communication
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World J Gastroenterol. Jul 28, 2006; 12(28): 4549-4552
Published online Jul 28, 2006. doi: 10.3748/wjg.v12.i28.4549
Functional activity of the rectum: A conduit organ or a storage organ or both?
Ahmed Shafik, Randa M Mostafa, Ismail Shafik, Olfat EI-Sibai, Ali A Shafik
Ahmed Shafik, Department of Surgery and Experimental Research, Faculty of Medicine, Cairo University, Cairo, Egypt
Randa M Mostafa, Department of Physiology, Faculty of Medicine, Sharkia University, Banha-Zagazig, Egypt
Ismail Shafik, Department of Surgery and Experimental Research, Faculty of Medicine, Cairo University, Cairo, Egypt
Olfat EI-Sibai, Department of Surgery, Faculty of Medicine, Menoufia University, Shebin El-Kom, Egypt
Ali A Shafik, Department of Surgery and Experimental Research, Faculty of Medicine, Cairo University, Cairo, Egypt
Correspondence to: Ahmed Shafik, MD, PhD, 2 Talaat Harb Street, Cairo 11121, Egypt. shafik@ahmedshafik. com
Telephone: +20-2-7498851 Fax: +20-2-7498851
Received: June 9, 2005
Revised: September 22, 2005
Accepted: July 10, 2005
Published online: July 28, 2006
Abstract

AIM: To investigate whether the degree of rectal distension could define the rectum functions as a conduit or reservoir.

METHODS: Response of the rectal and anal pressure to 2 types of rectal balloon distension, rapid voluminous and slow gradual distention, was recorded in 21 healthy volunteers (12 men, 9 women, age 41.7 ± 10.6 years). The test was repeated with sphincteric squeeze on urgent sensation.

RESULTS: Rapid voluminous rectal distension resulted in a significant rectal pressure increase (P < 0.001), an anal pressure decline (P < 0.05) and balloon expulsion. The subjects felt urgent sensation but did not feel the 1st rectal sensation. On urgent sensation, anal squeeze caused a significant rectal pressure decrease (P < 0.001) and urgency disappearance. Slow incremental rectal filling drew a rectometrogram with a “tone” limb representing a gradual rectal pressure increase during rectal filling, and an “evacuation limb” representing a sharp pressure increase during balloon expulsion. The curve recorded both the 1st rectal sensation and the urgent sensation.

CONCLUSION: The rectum has apparently two functions: transportation (conduit) and storage, both depending on the degree of rectal filling. If the fecal material received by the rectum is small, it is stored in the rectum until a big volume is reached that can affect a degree of rectal distension sufficient to initiate the defecation reflex. Large volume rectal distension evokes directly the rectoanal inhibitory reflex with a resulting defecation.

Keywords: Anal pressure; Rectal pressure; Rectometry; First rectal sensation