Facts and Controvesies

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


  • Anal continence is maintained by the Integrated effect of 4 Primary mechanical factors namely Intrarectal pressure, Dynamic viscosity of rectal contents and Anal canal Length and Diameter. The relative role played by each factor can be quantitated by its share in the flow equation.

  • The dynamic viscosity (D.V.) of soft well formed stools is 68.9 times that of air , while D.V. of watery stools is 38 times that of air , which explains why anal canal resistance to air is much lower than that to water, which is 1.8 times lower than that for soft well formed stools.

  • The controversy concerning the Anorectal angle (ARA): The ARA does not show itself in the flow equation and can be absent in the presence of adequate anal canal length and diameter maintaining adequate anal canal resistance. However owing to the visico-elastic properties of the anal canal pulling the anorectal junction upwards and forwards increases the anal canal length and decreases anal canal diameter and hence indirectly increases anal canal resistance to flow.

  • The absence of correlation between the presence of anal sphincter injuries as detected by U.S. or MRI and anal incontinence is explained by the fact that the injury should decrease anal canal length and increase anal canal diameter to a certain degree which would decrease the anal canal resistance enough to cause clinical and mathematic Anal Incontinence.



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