Anal reflex

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The anal reflex or perineal reflex is an external reflex and describes the reflex contraction of the external anal sphincter muscle ( muscle sphincter ani externus ) when the skin of the anus or the adjacent perineum or the supply area of ​​the superficial perineal nerve is touched. The anal reflex is the characteristic reflex for the spinal cord segments S3 – S5.

In animals there is also an involuntary pulling down of the tail. The afferent limb of the nerve perinealis superficialis , the efferent the nerve rectalis caudalis .

The same chain of reflexes is triggered by touching the base of the penis or the vulva , as the superficial perineal nerve is also stimulated here. This also leads to a contraction of the muscle bulbospongiosus why this reflex occasionally as Bulbospongiosusreflex or after the outdated name of the muscle, even Bulbocavernosusreflex is called.

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