The internal diameter of vertebral artery, 2.8mm, is below the normal range, which may be physiological or caused by pathologic stenosis. Due to individual differences, the normal vertebral artery internal diameter is about 3~5mm, if the whole vertebral artery internal diameter is less than 2mm, it is called physiological whole stenosis; if it is more than 2mm, but less than 3mm, it is called physiological whole fine. If the vertebral artery internal diameter of 2.8mm is limited, consider pathological stenosis, mainly related to atherosclerosis; mostly seen in people with hypertension, diabetes mellitus, hyperlipidemia, smoking, obesity, etc.; may appear dizziness, ataxia and other symptoms of ischemia in the posterior circulation. When the internal diameter of vertebral artery is found to be 2.8mm, it is recommended to consult a neurologist.