Leg numbness may be caused by factors such as leg compression and cold stimulation, or it may be a harbinger of diseases such as pyriformis syndrome and lumbar intervertebral disc herniation. 1. Compression, cold and other factors; if the patient maintains the same sitting position for a long time, or the legs are compressed, resulting in obstruction of blood circulation in the lower limbs, numbness of the legs will occur. At the same time, if the outside temperature is low recently, the patient’s leg warming measures are not appropriate, in the cold stimulation will slow down the blood circulation in the legs, will also cause leg numbness. 2. Piriformis syndrome: this disease belongs to the peripheral nerve compression disease, mainly due to acetabular fracture displacement, hip trauma bleeding, bone scab is too large, fiber contracture and other conditions. Patients often appear hip and lower limb radiating pain, some patients can also be accompanied by leg numbness phenomenon, if the patient’s pain is more intense, there can be unable to walk phenomenon. 3. Lumbar intervertebral disc herniation; this disease is more common in the clinic, mainly due to degenerative changes in the lumbar intervertebral disc. This disease often leads to lumbago, sciatica and other symptoms, when the lumbar intervertebral disc protrusion on the back of the nerve caused by compression, the patient will also appear lower limb numbness, lower limb weakness and other symptoms. Clinical causes of leg numbness, cerebrovascular disease, lower limb vascular disease can also be induced leg numbness, it is recommended that patients seek medical examination as soon as possible, to clarify the specific causes of the disease, timely treatment.