A flexible expandable inter vivos tube includes at least one arched segmented portion, a corresponding movable element and at least one positioning mechanism. The at least one arched segmented portion and corresponding movable element forming a flexible closed longitudinally expandable tube. The at least one arched segment includes an H-shaped connector having at least one cavity that allows variable slidable movement of a free end portion of the corresponding movable element. A flexible membrane is contained in the at least one cavity so that the hydraulic or air pressure within an inner rib of the H-shaped connector expands the movable element and, thus, the circumference and diameter of the flexible inter vivos tube are increased. A free end of the arched segment may include a retaining pin that engages a serrated free end of the corresponding movable element.
