Left hand numbness, most of the four factors are not related to the statement is not appropriate, its possible causes include physiological reasons, peripheral nervous system diseases, central nervous system diseases. 1. Physiological reasons: due to incorrect posture and other reasons, local compression, due to ischemia and hypoxia and the symptoms of hand numbness. After releasing the compression, it can be restored to normal in a short period of time. 2. Peripheral nervous system diseases: due to the peripheral nerve function is impaired and the left hand numbness symptoms, such as brachial plexus neuralgia or brachial plexus neuritis. Peripheral neuritis due to diabetes and nerve compression due to cervical disc herniation can also cause the above symptoms. 3. Central nervous system diseases: for example, when acute cerebral infarction, cerebral hemorrhage, etc., the patient may appear left hand numbness, which may be accompanied by slurred speech, dizziness and vomiting. The numbness of the left hand may also be related to other factors, and it is recommended that the patient should consult the doctor in time to clarify the cause and treat reasonably under the doctor’s guidance.