Patients can take the following ways to determine whether edema of the lower extremities appears: 1. They can take the way of observation. If edema appears in the lower extremities, it will first be manifested by the disappearance of the skin texture of the lower extremities, that is, the normal skin texture becomes very taut, and afterwards it is possible for the skin to become taut and shiny. If the swelling is very severe, there is also the possibility of tense blisters in this area. If several of these signs occur, it suggests the presence of edema. 2. Pressure can be applied. If pressure is applied to the area where edema is present, there will be a very obvious depression, and sometimes it may not recover in a short time. This situation is most obvious around the ankle joint and on the anterior medial side of the lower leg, that is, on the bone surface of the tibia.3. Bilateral comparison can be taken, that is, both lower limbs can be compared and observed to clarify whether there is swelling on one lower limb.4. Dynamic observation can also be taken. For example, the foot or the entire lower leg can be elevated with a pillow, sleep for one night, and then observe whether there is any abnormality in the diameter of the lower extremity in the morning and afternoon, to be able to clarify whether there is swelling of the lower extremity.