Respiratory assistance mask that allows respiratory gas (7) to come from a patient's lungs, coming from an external source, including said mask (1): - a hollow body (2), whose internal volume defines an internal chamber ( 3) provided with an inlet (4) of respiratory gas intended to be attached to said source, - an opening (8) constituting the outlet of respiratory gas and which is intended to be attached to a respiratory tract of said patient, and - a flexible support member (11) that borders the contour of said opening (8) and that is intended to be sandwiched between the face (9) of said patient and said hollow body (2), said flexible support member being an inflatable weatherstrip or a closed cell foam weatherstrip； including the mask, in addition: a flexible membrane (13) incorporated on said weatherstrip (11) and suitable for interposing between said weatherstrip (11) and the face (9) of said patient, said flexible membrane (13) presenting a more flexible important than that of the weatherstrip (11)； and characterized in that the mask includes: - a multi-perforated internal skirt (14) incorporated, by one of its two contours (14E), on said weatherstrip (11) and wrapped, at least partially, by said flexible membrane (13), extending the free contour (141) of said skirt in the direction of said internal chamber (3), so that respiratory gas (7) is suitable to pass through the perforations (15) of said skirt (14), from said inlet (4), for tighten said membrane (13) and apply it tightly against the patient's face (9).Mascarilla de asistencia respiratoria que permite llevar, a los pulmones de un paciente, gas respiratorio (7) que proviene de una fuente exterior, incluyendo dicha mascarilla (1): - un cuerpo hueco (2), cuyo volumen interno define una cámara interna (3) provista de una entrada (4) de gas respiratorio destinada a estar unida a dicha fuente, - una abertura (8) que constituye la salida de gas respiratorio y que está destinada a estar unida a una vía respira
