Defecation Norm Gram

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The Equation
Flow Index calculator
Flow Index contispation
Defecation Norm Gram
Anal Incontinence
Continence Norm Gram
Applications of use of the Theory
Facts and Controversies

  • The 4 primary factors involved in the flow equation could be successfully plotted in order to facilitate understanding the mechanism of normal defecation and continence and to allocate the majority of the patients into normal or abnormal physiology by simply plotting the line connecting the A.C. Length and Diameter during attempted defecation against the line connecting the mean Intrarectal Pressure during attemted defecation and Point M (see the norm gram) where the meeting of the 2 lines allocate the patient in its corresponding functional status. The above mentioned measurements are applied directly to the norm gram as mmHg and cm. Without conversion to the SI units.

    Example: IRP = 52 mmHg.

    A.C. Length = 2 cm.

    A.C. Diameter = 2.3 cm.

    Calculated flow index = 1.8 cc. Barium Sulphate/S.

    Norm gram grade I

  • A flow index of 1cc/s. was taken as well as a cut off point between obstructed defecation (flow < 1cc/s.) and unobstructed flow in the absence of anatomical obstruction or excessively hard stools during defecation.


  • Where Zone I includes :

    1. Normal unobstructed defecation.
    2. Patients who have constipation due to hard stools, Colonic Inertia, or mechanical factor such as Rectocele or Intussusceptions who is expected to regain normal defecation after correction of the cause.

Zones II, III and IV: Include patients with underlying Anismus and/or Rectal Inertia.

Zone II: Obstructed defecation for soft well formed stools.

Zone III: Obstructed defecation for watery stools.

Zone IV: Obstructed defecation for Gas.


  • The minimum normal anal canal resistance was represented by the line connecting A.C. Length 2 cm. And A.C. Diameter =2 cm.

  • And The minimum normal Intrarectal pressure was represented by line connecting IRP.=50 mmHg and point M.

  • Defining Anismus, rectal inertia, combined cases and normal controls.

  • Some of Anismus patients lie in zone I of normal defecation being compensated for by increased Intrarectal pressure during defecation which had led to the controversies about the role of Anismus in constipation .

  • Those cases are compensated Anismus patients who should not be recruited as normal controls, who should be recruited only from the control area above and in- front of both lines.

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