A push-button for a dispensing system for a liquid under pressure, the push-button includes a body having a mounting well on a delivery tube for the liquid under pressure and a housing in communication with the well, the housing being provided with an anvil around which a spraying nozzle is mounted in such a way as to form a dispensing path of the fluid between the housing and a vortex unit including a vortex chamber provided with a dispensing orifice as well as at least one supply channel of the chamber, the nozzle having a proximal wall wherein is formed a print of the vortex unit and the anvil having a distal wall whereon the proximal wall of the nozzle is pressing against in order to delimit the vortex unit between them, the distal wall having a recess which is formed across from the print of the vortex chamber, the maximum depth of the recess being between 25% and 300% of the minimum depth of the print of the supply channels.