There are several reasons for numbness on the left side of the body: it may be due to nerves, which may be the central nervous system, such as the brain, with some ischemic lesions or bleeding in the brain or some degeneration of the nervous system. The central nerve also includes some conditions of the spinal cord, a herniated disc or frozen shoulder or cervical spondylosis, which may cause numbness in half of the body. Vascular causes, insufficient blood supply to one side of the body due to arterial insufficiency, cause nerve lesions and sensory numbness, such as atherosclerotic numbness. There is also a part of numbness and plant nerve dysfunction related.