The disclosure relates to a corner structure which is suitable for a sealed and thermally insulating tank for storing a fluid comprising a secondary thermal insulation barrier which is retained on a carrier structure, a secondary sealing membrane, a primary thermal insulation barrier and a primary sealing membrane which is intended to be in contact with the fluid contained in the tank, the corner structure comprising: a first panel and a second panel forming a corner of the secondary thermal insulation barrier, and comprising an external face intended to move opposite the carrier structure and an internal face; a corner arrangement of the secondary sealing membrane, which arrangement is fixed to the first and second panels; a first insulating block and a second insulating block of a primary thermal insulation barrier which are fixed to the first and second panels, respectively, and which rest against the corner arrangement of the secondary sealing membrane; and a corner of a primary sealing barrier comprising a first wing and a second wing which are fixed to the first and second insulating blocks, respectively.