The causes of calf distension include varicose veins of the lower limbs, acute cellulitis, hypothyroidism and so on. 1. Varicose veins of the lower limbs: If the patient suffers from varicose veins of the lower limbs, due to the dysfunction of the venous valves of the lower limbs, venous reflux is blocked, resulting in tortuous veins and anguished veins, leading to oedema, swelling and other symptoms of the lower limbs. 2. Acute cellulitis: Bacterial infection of the lower limbs due to trauma, triggering the formation of inflammatory infections in the skin and mucous membrane tissues of the lower limbs, and constant stimulation of inflammatory factors, leading to localized redness, swelling and pain in the lower limbs of the patients. 3. Hypothyroidism: If the patient himself suffers from hypothyroidism, due to insufficient production of thyroid hormone or weakening of the role of thyroid hormone, triggering the metabolic dysfunction of the patient’s whole body, which leads to mucous membranes of the lower limbs, edema, swelling and so on. There are many reasons for calf swelling, we suggest that patients go to the hospital in time, complete the relevant examinations, clarify the cause of the disease, and follow the doctor’s instructions for treatment.