The cause of numbness in the middle finger of the left hand may be related to mechanical compression, or it may be caused by cervical spondylosis, carpal tunnel syndrome, stroke and other reasons. 1. Mechanical compression: commonly seen in sleeping, if the left middle finger is inadvertently pressurized for a long time, resulting in poor blood circulation in the finger, it may cause numbness of the left middle finger. For this situation, by changing the sleeping position, lifting the compression, appropriate activities, is conducive to quickly make the symptoms disappear. 2. Cervical spondylosis: especially in patients with cervical disc herniation, the protruding cervical discs are easy to compress the local nerve roots, resulting in sensory and motor dysfunction of the parts innervated by the compressed nerves, which may cause numbness in the middle finger of the left hand, and may be accompanied by neck and shoulder pain, dizziness and other symptoms. 3. Carpal Tunnel Syndrome: This disease can lead to the compression of the median nerve, which innervates the sensory and motor functions of the thumb, index finger, middle finger and part of the ring finger. Therefore, after suffering from carpal tunnel syndrome, due to the compression of the median nerve, numbness of the middle finger of the left hand may occur. 4. Stroke: Stroke patients with hemiplegia, hemiparesis, hemisensory deficits, there may be a side of the upper limb numbness, numbness in the left hand, including the middle finger. The numbness of the left middle finger may be related to other factors. If the symptoms continue to be unrelieved, the patient should consult a doctor as soon as possible to clarify the causes and then give targeted treatment.