Abstract: Tubular structure having at least two tubes (20, 20?) and a plug-in tube connection (10) which comprises a flange (1), wherein said flange (1) serves as an axial stop surface for terminal ends (21, 21?) of the two tubes (20, 20?). Each side of the flange (1) is equipped with at least one lug (3) in order to engage in a corresponding cutout (22) in the terminal end (21, 21?) of the respective tube (20, 20?), wherein the lugs (3) engaging in the cutouts (22) prevent the tubes (20, 20?) from twisting relative to one another. On each side of the flange (1) is provided a cylinder portion (5, 5?) which can be plugged into the inside of the respective tube (20, 20?). In addition, each cylinder portion (5) has an axial gap (7), resulting in flexible endpieces (9A, 9B) above and below the gap. The first flexible endpiece (9A) has a radial bore (11) with a screw element (13) for tightly clamping the tube connection (10) in the tube (20, 20?).