In this study the author emphasizes the existence of a muscular element that had not been described until now. This muscular element is situated around Malpighi's pyramid and its fibres are followed by the caliceal muscle and the elements that form Henle's peripapillar ring. The systolic and diastolic function of this peripyramidal muscle can be observed in the urographies, during the evacuation of the collector tubules of Bellini, and its synchronization with the next caliceal and pyelic musculature.