The mattress (1) has an elongate chamber comprising a planar main wall (5a) and another planar main wall braced by flexible links that are formed of drop-stitch yarns and are resistant to inflation pressure of the mattress. The chamber is extended by two raised lateral strips (15a, 15b) on both sides of a base (9) beyond a transition area where the braced walls are close to each other. A seam, at the location of the transition area, brings the walls together for causing a fold between the base and each strip, where the seam and the walls are covered by sealed lining walls at folded areas.Il sagit dun matelas gonflable (1) comprenant une enceinte (3) délimitée par deux parois principales (5a, 5b) sensiblement planes, approximativement parallèles, étanches aux gaz, entretoisées par des liens souples (7). Lenceinte (3) définit un fond (9) et se prolonge de part et dautre de celui-ci, au-delà dune zone de transition (13a, 13b, 17) où les deux parois principales entretoisées (5a, 5b 50a, 50b) sont plus proches, par deux bandes latérales relevées (15a, 15b) de sorte à flanquer latéralement la personne (11).
