A sheath for covering an intravenous device to shield the device from a patient’s skin. The turbofan jet engine further includes at least one monoblock arm for the connection of ancillaries between the outside of the external casing and the inside of the shell, placed parallel to a radial arm. The angle, and optionally the height, of the back support with respect to the base is selectively adjustable, optionally over a continuous range, by changing the location where the rail attaches to the rail support.