Slight numbness of the left leg may be related to the following causes: 1, there may be peripheral neuropathy, the most common is the lumbar intervertebral disc herniation or some of the lower extremity nerves localized compression, both diseases can lead to the distribution of the nerve area to produce a series of symptoms of radiating pain, numbness. In addition, numbness of the lower extremities may also occur during certain cervical spondylosis episodes, such as spinal cord cervical spondylosis. 2, there may be peripheral vascular lesions, such as the presence of deep vein thrombosis or thromboembolic vasculitis, both of which can lead to the distal lower extremity blood supply restrictions, which will result in the production of coldness, purplish, and numb. 3, there may be a central nervous system disease, such as the cerebral cortex. The central nervous system lesions, such as cerebral cortical lesions may cause limited numbness of one side of the limbs. 4, there may be complications of diabetes mellitus, if the patient’s long-term blood sugar is too high, may make the peripheral nerves to produce related lesions, which will be manifested in one side of the limbs with numbness.