Instability of the fifth cervical vertebra, i.e., the loss of stability of the fifth cervical vertebra, under physiological loading, there is a series of symptoms induced by displacement beyond the normal range, mainly manifested as the loss of cervical vertebral stability, compression of the peripheral nerves, and symptoms of pain. 1. Loss of stability of cervical vertebrae: when twisting the neck or performing forward and backward flexion and extension, the cervical vertebrae move more widely, which may stimulate the surrounding soft tissues and cause discomfort of the cervical and back muscles, such as cervical stiffness, muscle tension and spasm, and other symptoms induced by local pain. 2. Compression of peripheral nerves: If the brachial plexus nerve is compressed, numbness and weakness of the limbs in the innervated area, as well as inflexibility and stiffness of the fingers may occur. When the compression to the central nervous system, there may be a feeling of girdle in the chest and numbness and weakness in both lower limbs, unsteady walking, and a feeling of stepping on cotton. 3. Pain: Pain in the precordial area of the chest, i.e. in front of the heart, may stimulate the surrounding tissues and cause pain in the back of the patient. Therefore, it is necessary to make a clear diagnosis through the systematic examination of imaging. Related patients are advised to seek medical treatment in time to avoid delaying the condition.