Abstract: An inflatable balloon structure (10) for catheters, such as a catheter for angioplasty or for depositing an endolumenal prosthesis or stent in a duct, for example, a vascular duct, the balloon structure being of predominant longitudinal extent with a proximal end and a distal end, and being suitable for performing an expansion in an object to be dilated, the balloon comprising a wall which has, transverse the longitudinal extent, at any point, an annular cross-section delimited externally by an outer surface which, at least in an intermediate portion thereof, is suitable for coming into contact with the object to be dilated, and internally by an inner surface which delimits an inflation chamber, in which at least one wall cavity (19) is provided in the wall and is formed within the annular cross-section which delimits the inflation chamber so as to be disposed between the outer surface and the inner surface, the cavity extending without interruptions and/or openings, longitudinally relative to the balloon str