There are many possibilities for weak legs, including orthopedics, neurology, cerebral surgery, endocrinology and other disciplines, so we have to combine the systemic manifestations and related medical history with clinical examination results to determine which department to go to. If there is sudden generalized weakness, weakness of the lower limbs, fear of heat, excessive sweating, palpitations or acute gastroenteritis with little food, hypokalemia should be considered and the endocrinology department should be consulted. If there is a combination of dizziness, weakness, orofacial deviation, previous history of hypertension and cardiovascular disease, etc., consider stroke, etc., and refer to neurology. If dizziness and change of position are obvious, consider the lumbar spine and cervical spine problems, you can call orthopedics.