SEAT BACKREST FOAM, BACKREST AND MOUNTING METHOD THEREOF

A seat backrest foam comprising a first headrest area (11) and a second backrest area (12), the first headrest area (11) and the second backrest area (12) forming a single foam body (1), the foam defining a window (13) passing through from a first surface of the foam, supporting a seat occupant, to a second surface of the foam, located opposite the first surface, and further comprising at least one block (4) disposed adjacent to a wall of the foam defining the window and mechanically linked to said wall by a joining line (8), wherein the block forms a single body with the foam (1) and is configured to rotate 180° about the joining line. The invention also relates to a backrest containing the foam and to the method of mounting the backrest.