A backrest includes first and second side wings and connectors configured to connect the first and second side wings to the wheelchair frame. The first side wing comprises a plurality of transverse profiles extending towards the second side wing and the second side wing comprises a plurality of second transverse profiles extending towards the first side wing. At least one first transverse profile of the first side wing and at least one associated second transverse profile of the second side wing are at least partially mutually embraced in a slidable manner. The at least one first transverse profile and the at least one second transverse profile are dimensioned and configured so that the mutual slidably embracement of the at least one first transverse profile and the at least one second transverse profile is made on a range of distances enabling the width adjustment of the backrest.
