The tendons in the legs, or superficial veins, are more visible and may be caused by several reasons: 1. They may be caused by the patient being too thin. If the patient is thin, the more superficial veins will become very obvious, more obvious when the patient is overactive or in hot weather. 2. It may be caused by prolonged standing. The blood circulation of the lower limbs may slow down significantly due to prolonged standing, and the blood will pool inside the veins of the lower limbs, causing the superficial veins to become more obvious. 3, it may be caused by varicose veins. This kind of disease is often due to the patient standing for a long time, or the lower limbs have often been cold, and then lead to the superficial veins of the lower limbs, such as the small saphenous vein, the saphenous vein appeared inside the vein inflammation, and there are varicose veins occur. In this case, the superficial veins on the surface of the body will be very obvious.4. It may also be caused by the presence of deep vein thrombosis. If the patient has an embolism inside the large veins of the lower limbs, it may cause the superficial veins of the lower limbs to become more obvious. Finally, this condition may also be caused by high blood pressure. The superficial veins may become more pronounced due to high blood pressure levels in the patient.