The underlying lesions of cervical spondylosis are straightening of the physiological curvature of the cervical spine, osteophytes of the cervical spine, herniated cervical intervertebral discs, and ligament calcification. Numbness of the upper extremities can occur when any of these underlying lesions lead to nerve root compression. The extent of numbness in the upper extremities may vary depending on the location of the lesion that causes compression of the nerve root. For example, a herniated cervical disc to the left or right, or osteophytes in the hook vertebral joints, which lead to compression of the nerve root foramina, can lead to numbness in the upper extremities. Doing an MRI can basically clarify the specific location, as well as the severity and subsequent need to take the appropriate treatment means, the less severe can be treated through acupuncture, cervical traction, or oral methylcobalamin, vitamin B and other neurotrophic drugs to alleviate the symptoms. In severe cases, these conservative treatments are not effective and surgery is needed.