If the patient’s legs are thin in the morning and become thicker after a while, it usually belongs to the edema of the lower limbs. If the edema of the lower limbs occurs, there are several factors as follows: 1. In the case of some organic diseases, such as cardiac insufficiency and renal insufficiency, there will be a situation that the water can not be fully operated, and the water can not be fully utilized and metabolized by the body, so there will be a case that the legs are thin in the morning and appear to have edema and puffiness after a while. 2. In some basic metabolic diseases, such as thyroid insufficiency and hypoadrenocorticism, anterior cervical mucus edema may occur. 3. Malnutrition may lead to generalized swelling, and localized and lower limbs may show obvious thickening and edema. 4. In the case of arterial and venous vascular insufficiency in the lower limbs, or deep venous thrombosis in the lower limbs, the legs may be thin in the morning. 5. In the case of arteriovenous occlusion of the lower limbs and deep vein thrombosis and embolism of the lower limbs, the legs will be thin in the morning and swollen after a while due to blood vessels.