It is described a foldable articulated arm comprising a first rod-shaped element, a second rod-shaped element and a third rod-shaped element foldable one another and at least three stretching element of the rod-shaped elements, arranged to form a system of four-bar linkages, further comprising a plurality of joint elements of the rod-shaped elements and the stretching elements and having, at the opposite ends, a retaining mechanism for a respective combining with a tube and an umbrella sheet, wherein the rod-shaped elements, the joint elements, the stretching elements and the retaining mechanism are all made integral in a single piece of plastic material constituting the foldable articulated arm.