Seat comprising a part (100) for back support with adjustable surface profile, comprising an adjustable central column (101) located along the direction of the height of the part (100) for back support and which it comprises a plurality of supports (110, 210, 211, 310) and a plurality of side pieces (120, 220, 221, 320) fixed to the supports (110, 210, 211, 310) and substantially extending in the direction of the width of the part (100) for support of the back to profile the surface of the part (100) for support of the back, which further comprises means (130) for interlocking the profile coupled to a plurality of supports (110, 210, 211, 310) and which can be adjusted to a non-locked configuration, in which the profile of the surface of the part (100) for back support is adjustable, and to a locked configuration, in which each of The brackets (110, 210, 211, 310, 410) are fixed with respect to the others and the surface profile of the part (100) for back support is interlocked, characterized in that the supports (110, 210, 211, 310) are coupled to neighboring supports (110, 210, 211, 310) directly or through dividers (240, 340), by means of a spherical joint configured in such a way that, in the non-interlocked configuration of the profile interlocking means (130), the supports (110, 210, 211, 310) can be rotated individually around a plurality of axes with respect to the neighboring supports (110, 210, 211, 310)Asiento que comprende una parte (100) para apoyo de la espalda con perfil superficial ajustable, que comprende una columna (101) central ajustable situada a lo largo de la dirección de la altura de la parte (100) para apoyo de la espalda y que comprende una pluralidad de soportes (110, 210, 211, 310) y una pluralidad de piezas (120, 220, 221, 320) laterales fijadas a los soportes (110, 210, 211, 310) y que se extienden substancialmente en la dirección de la anchura de la parte (100) para apoyo de la espalda para perfilar la superficie de la parte (100) para
