[The colo-sphincteral reflex. Critical review of the physiological mechanisms of defectation]

A colosphincterometrographic study in 40 normal subjects revealed the existence of a colosphincteral reflex hitherto unknown to man. In all cases, insufflation of 30-40 cc air into a balloon placed 50 cm from the anus produced a relaxation of the internal sphincter muscle of the anus (colosphincteral reflex), a subjective feeling of imminent defaecation, and reflex contraction of the external sphincter muscle. The discovery of this new reflex suggests that the physiological mechanism of defaecation may even commence above the ampulla recti, which has always been regarded as the only reflexogenic segment of the large intestine.