Clinical manifestations of lower limb venous disease: a. Sudden unilateral lower limb swelling and pain; b. Lower limb thigh and calf veins are tortuous and grouped; c. Local hardness and pressure pain in the lower leg; d. Itchy lower leg skin, which may be accompanied by eczema; e. Soreness and discomfort in the lower leg after standing for half an hour; f. Darkening of the lower leg skin; g. Calf edema, which is light in the morning and heavy at night; h. Calf ulcers do not heal easily.