Limited stenosis of the v4 segment of the left vertebral artery may be due to cervical spondylosis, vertebral arteriosclerosis, congenital stenosis of the vertebral artery and other diseases. 1. Cervical spondylosis: When the patient develops cervical spondylosis, cervical spondylotic hyperplasia compresses the left vertebral artery v4 segment, which may cause limited stenosis of the lesion locally. 2. Vertebral artery sclerosis: if the patient has vertebral artery sclerosis, the left vertebral artery v4 segment localized lipid plaque formation, it may cause limited stenosis. 3. Congenital stenosis of vertebral artery: If the patient has congenital stenosis of the left vertebral artery v4 segment in the course of congenital development, the vertebral artery at the site of lesion may be caused to become significantly narrowed. There are many causes of limited stenosis of the left vertebral artery v4 segment, so it is necessary to go to the hospital, according to different conditions, under the guidance of the doctor for treatment.