A leg thick and a leg thin common causes are the following two: First, the formation of venous thrombosis of the lower extremities will cause significant swelling of the affected limbs, manifested as thickening of the limbs, at this time the patient needs to be given as soon as possible to the subcutaneous injection of low molecular heparin, oral aspirin antiplatelet aggregation, double lower extremity stockings, to promote the return of blood flow to the lower extremities, if necessary, the inferior vena cava filter implantation, to prevent the thrombus dislodgment caused by pulmonary embolism and other serious complications, this treatment can be beneficial to the absorption and dissolution of thrombus, and restore the normal shape of the limbs. Such treatment can be beneficial to the absorption and dissolution of thrombus in the affected limbs, and restore the normal limb shape. Second, after the fracture caused by trauma, the affected limb lacks sufficient exercise, resulting in muscle atrophy and limb thinning, at this time, the patient can gradually restore the normal shape by strengthening the muscle exercise.