The swelling of the instep may be caused by physiological factors such as sedentary activities, or it may be related to pathologic factors such as malnutrition, kidney disease, hypothyroidism, etc. 1. Physiological factors: Sitting for a long time can lead to localized compression, affecting the blood circulation of the lower limbs, thus resulting in the symptoms of dorsal swelling. 2. Pathological factors (1) Malnutrition: malnutrition can lead to hypoproteinemia and depressed edema of the lower limbs. Vitamin B1 deficiency can also cause dorsal swelling. (2) Kidney disease: eyelid edema and lower limb edema can occur, usually more obvious in the early morning when waking up. (3) Hypothyroidism: anterior tibial mucous edema can occur, mainly in the lower third of the anterior tibia, but also on the instep. There are many causes of dorsal swelling of the feet, and it is recommended to go to the hospital in time to find out the cause and treat it in time.