The relation of sensation in the anal canal to the functional anal sphincter: a possible factor in anal continence

Duthie, H. L.; Bennett, R. C.

doi:10.1136/gut.4.2.179

Cited by 263 publications

(62 citation statements)

References 3 publications

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“…The anal canal has a rich supply of nerve endings at the level of the anal skin, while the rectum senses mechanical distention through mechanoreceptors deep in-between the muscle layers of the gut wall. In consequence, rectal perception has a high threshold and is diffuse in localization (Goligher et al, 1951), while anal sensation is precise in localization, possesses a low threshold, and allows precise discrimination (Duthie et al, 1963). While it is conceivable that such differences in peripheral processing of sensory information would result in differences in cortical processing of this information, this has not been investigated for the anorectum so far.…”

Section: Introductionmentioning

confidence: 99%

Cerebral Activation during Anal and Rectal Stimulation

et al. 2001

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While the rectum is innervated by visceral afferents, the anal canal is innervated by the somatosensory pudendal nerve. The representation of these two central domains of intestinal sensations in the human brain is largely unknown. Nonpainful pneumatic stimulation of the anal canal and the distal rectum using event-related functional magnetic resonance imaging (fMRI) was performed in eight healthy subjects. Subjective scaling of sensations revealed no differences in unpleasantness and pain during both stimuli. Both types of stimuli revealed fMRI activation in secondary somatosensory, insula, cingular gyrus, left inferior parietal, and right orbitofrontal cortex. Anal stimulation resulted in additional activation of primary sensory and motor cortex, supplementary motor area, and left cerebellum. We concluded that viscerorectal and somatosensory anal stimulation predominantly differ in their primary sensory activation and additional activation in motor areas. This motor response following aversive somatosensory stimuli may be caused by a reflexive avoidance reaction which is not observed after the more diffuse experienced visceral stimulation.

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Section: Introductionmentioning

confidence: 99%

Cerebral Activation during Anal and Rectal Stimulation

et al. 2001

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“…Although others have studied the mechanism of action of the anal sphincter (15)(16)(17), our design was not to study the rectum and anus as such but simply to investigate the meaning of pressures recorded from an easily accessible sphincter. Although we do not claim that our results can be directly applied to the gastroesophageal sphincter, we do feel that they may challenge the general concept that alimentary tract sphincters prevent flow by creating a barrier of pressure.…”

mentioning

confidence: 99%

“Squeeze” vs. Resistance: An Evaluation of the Mechanism of Sphincter Competence*

Harris¹,

Pope²

1964

J. Clin. Invest.

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“…It is thought that the consequence of relaxation of the internal sphincter, induced by rectal distension, is that it, enables the sensitive zone of the anal canal to sample the rectal contents (Duthie & Bennett, 1968). If contents are solid or liquid and conditions are inappropriate for defaecation, then conscious contraction of the external sphincter and pelvic floor forces contents back into the rectum.…”

Section: Discussionmentioning

confidence: 99%

“…At the same time there is a reflex contraction of the external anal sphincter. It is assumed that a similar relaxation ofthe internal sphincter occurs when the rectum is distended with faeces and allows the faecal bolus to descend and come into contact with sensory receptors in the anal canal (Duthie & Bennett, 1968). If conditions are inappropriate for defaecation, reflex contraction of the external sphincter and recovery of the tone of the internal sphincter force contents back into the rectum, and hence preserve continence (Schuster, Hendrix & Mendeloff, 1963).…”

Section: Introductionmentioning

confidence: 99%

Ano‐rectal activity in man during rectal infusion of saline: a dynamic assessment of the anal continence mechanism.

Haynes¹,

Read²

1982

The Journal of Physiology

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SUMMARY1. Anal and rectal pressures and the external anal sphincter electromyogram were recorded in eighteen normal subjects at rest and during rectal infusion of 1500 ml. saline at a rate of 60 ml./min.2. During saline infusion, the recordings described a pattern of regular relaxations of the internal sphincter associated with contractions of the rectum and the external anal sphincter. The frequency of ano-rectal pressure fluctuations increased as the infusion progressed.3. The peaks in rectal pressure were always lower than the lowest anal pressure in all normal subjects tested.4. External sphincter contractions only occurred in association with 60 % of internal anal sphincter relaxations and did not prevent the maximum decrease in anal pressure. These observations suggest that phasic contraction of the external anal sphincter does not play a major role in maintaining continence.

show abstract

The relation of sensation in the anal canal to the functional anal sphincter: a possible factor in anal continence

Cited by 263 publications

References 3 publications

Cerebral Activation during Anal and Rectal Stimulation

Cerebral Activation during Anal and Rectal Stimulation

“Squeeze” vs. Resistance: An Evaluation of the Mechanism of Sphincter Competence*

Ano‐rectal activity in man during rectal infusion of saline: a dynamic assessment of the anal continence mechanism.

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