The idiom "束手无策" is formed through a vivid metaphorical structure: "束" (to bind) + "手" (hands) creates the image of having one's hands tied, symbolizing restriction and inability to act, which is then compounded by "无" (without) + "策" (strategy or plan), meaning to have no course of action or solution. Thus, the entire phrase literally paints a picture of being bound and without a plan, which figuratively conveys a state of utter helplessness, desperation, and having no means to deal with a difficult situation. This formation follows a common Chinese idiomatic pattern where a concrete physical scenario is used to express an abstract psychological or circumstantial state.