Numbness of the fingers of the left hand may be related to too much exertion, or it may be caused by cervical spondylosis, peripheral neuritis, carpal tunnel syndrome and other reasons. 1. Too much exertion: for example, if the left hand is engaged in hand work for a long time, resulting in overwork of the left hand, it may cause numbness of the fingers of the left hand, which may also be accompanied by pain, weakness and other manifestations. 2. Cervical spondylosis: the cervical intervertebral disc degeneration, resulting in intervertebral joints and ligaments and other tissues degeneration, and degenerative tissues are prone to adjacent blood vessels, nerves caused by compression, may show left hand numbness of the fingers, may also be accompanied by stiffness of the neck and shoulders, pain and other symptoms. 3. Peripheral neuritis: the peripheral nerves of patients with this disease are damaged, causing sensory impairment at the distal end of the limb, which may cause numbness in the fingers of the left hand, accompanied by swelling of the fingers, inflexible movement and other manifestations. 4. Carpal tunnel syndrome: When the median nerve passes through the wrist, the narrow carpal tunnel is compressed and induces symptoms. Numbness or pain is often felt in all three fingers, with the middle finger being the worst. Symptoms are most severe at night or early in the morning and can be relieved by shaking the wrist appropriately. Numbness in the fingers of the left hand may also be caused by other reasons. If the symptoms do not get better, you should consult a doctor as soon as possible.