The numbness of the left middle finger may be caused by cervical spondylosis, carpal tunnel syndrome, cerebral thrombosis and other diseases. 1. Cervical spondylosis: if you often lower your head or sit for a long time, you will be prone to cervical spondylosis, which leads to local nerve compression, causing numbness in the middle finger of the left hand and accompanied by neck pain, dizziness and other symptoms. 2. Elbow tube syndrome: when patients have elbow osteoarthritis, elbow tumors, etc., it is easy to lead to ulnar nerve compression, resulting in elbow tube syndrome, numbness of the hand, pain and other symptoms. 3. Cerebral thrombosis: If the patient has high blood pressure or when the blood pressure rises sharply, it may lead to atherosclerosis and cerebral thrombosis, resulting in numbness of the middle finger of the left hand, crookedness of the eyes and mouth, weakness, and slurred speech, etc. The patient may also experience numbness of the middle finger of the left hand. Patients with numbness in the middle finger of the left hand should go to the hospital in time, and be judged by the doctor and given appropriate treatment.