Numbness in the left leg of a man may be due to cervical spondylosis, diabetic peripheral neuropathy, lumbar lesions and other diseases of the omens. 1. Cervical spondylosis: commonly seen in spinal cervical spondylosis, which can easily lead to local spinal cord, nerve root compression, resulting in dysfunction of the area innervated by the compressed nerves, which may cause numbness in the left leg, and may be accompanied by numbness of the upper extremities, weakness, walking as if on cotton, and other symptoms. 2. Diabetic peripheral neuropathy: this disease can lead to damage to the peripheral nerves, nerve endings blood circulation is impaired, which may cause numbness of the left leg, may also be accompanied by numbness of the hands, feet and other symptoms. 3. Lumbar lesions: due to the sciatic nerve compression, it may cause the left leg to produce radioactive numbness, may also be accompanied by lumbar pain, numbness of the feet and other symptoms. Common diseases are mainly lumbar disc herniation, lumbar spinal stenosis, pear-shaped muscle syndrome. Men’s left leg numbness, may be caused by other reasons, if accompanied by obvious symptoms of discomfort, should be as early as possible to seek medical attention, through the improvement of the relevant examination, diagnosis of the causative factors, by the doctor’s guidance for treatment.