Lying down for a long time left thigh numbness, may be localized pressure and other physiological factors, may also be sciatica, lumbar disc herniation, etc., need to be targeted to take general treatment, drug therapy, massage physiotherapy, surgery and other methods of treatment. 1. Physiological factors: mainly due to the long-term maintenance of a position resulting in local localized pressure, causing poor blood circulation and peripheral nerve pressure and numbness of the left thigh, change the posture, move the body to relieve the symptoms of numbness of the legs. 2. Sciatica: the sciatic nerve is squeezed when it passes through the pear-shaped muscle, which can lead to numbness in the nerve distribution area and numbness in the thigh. Local hot compresses and massage can be given to relax the muscles, and non-steroidal drugs such as ibuprofen and acetaminophen can be taken as prescribed by the doctor. 3. Lumbar disc herniation: caused by the continued compression of the nucleus pulposus on the nerve root, usually try to avoid bending over and bearing weight, localized hot compresses, ultra-short wave and other physical therapy, oral non-steroidal drugs such as ibuprofen to relieve pain, some patients may need surgery. Lying down for a long time left thigh numbness, if the symptoms continue to get no relief, you should go to the hospital in a timely manner, to identify the cause of targeted treatment.