The numbness in the thighs is mainly due to four reasons: 1. the herniated discs and bony stenosis of the lumbar region, which produce extrusion and stimulation of the nerve roots, resulting in ischemia of the nerve bundles, which can cause numbness in the lateral and posterior thighs. 2. sciatica, that is, when the sciatic nerve passes through the pear-shaped muscle, it is squeezed by the edema and hyperplasia of the pear-shaped muscle, which can lead to numbness in the nerve distribution area, which can also cause numbness. 3. 3, gluteal epicutaneous neuritis, the gluteal epicutaneous nerve by the skin, subcutaneous tissue and the surrounding muscles and other soft tissue stimulation, there will also be nerve ischemia, there will be a little numbness in the thigh, usually not more than the knee. 4, local peripheral nerves, small nerves from the muscle penetration by stimulation extrusion, there will also be numbness in the thigh.