In the clinic, the causes of left hand weakness are still very many, the most common consideration is caused by the following situations: 1, the patient’s recent period of excessive strain, which can cause local muscle strain, thus causing left hand weakness; 2, the patient if there is a fracture, subluxation, prolonged fixation of inactivity can cause joint stiffness, muscle atrophy, thus causing hand weakness; 3, if If there is cervical spondylosis, especially the nerve root cervical spondylosis causes obvious pressure on the nerve root, which will also cause the patient to have hand weakness; 4. If there is cerebral infarction, cerebral hemorrhage or brain tumor, it will also cause the patient to have left hand weakness.