Pain from the knee down to the top of the foot may be caused by vascular diseases of the lower limbs, nerve compression and so on. 1. Lower extremity vascular diseases: venous return obstruction or arterial occlusion in the lower extremity can lead to increased venous pressure, blood stasis in the veins, and pain, while the reduction of arterial blood can also occur in the limb ischemia, hypoxia, which can also lead to pain in the limb. Common diseases, such as varicose veins of the lower limbs, deep vein thrombosis, arterial occlusive vasculitis and so on. 2. Nerve compression: the knee to the top of the foot is mainly innervated by the peripheral peroneal nerve. Various causes of peroneal nerve compression or injury may be manifested as symptoms of pain below the knee to the top of the foot, such as popliteal cysts of the knee, knee trauma, etc. In addition, the peroneal nerve, which is responsible for transmitting the peripheral nerve, can also cause pain. In addition, when the spinal nerves responsible for conducting sensation and movement of the common peroneal nerve are compressed, the above symptoms may also be manifested, such as lumbar disc herniation, spinal stenosis, and so on. If the pain is not relieved or is accompanied by other symptoms, it is important to go to the hospital to get a clear picture of the cause of the pain and then give targeted treatment.