Posterior circulation ischemia refers to transient ischemic attack (TIA) of the carotid system and cerebral infarction in the posterior circulation. Synonyms include ischemia of the vertebrobasilar system, TIA of the posterior circulation with cerebral infarction, vertebrobasilar artery disease, and vertebrobasilar thromboembolic disease. Given that MRI diffusion-weighted imaging reveals that about half of posterior circulation TIAs have definite infarct changes and the boundary between TIA and cerebral infarction is becoming increasingly blurred, the use of posterior circulation ischemia to cover TIAs of the posterior circulation with cerebral infarction is beneficial for clinical operation. 1. Common symptoms of posterior circulation ischemia Dizziness/vertigo, limb/head and face numbness, limb weakness, headache, vomiting, diplopia, transient loss of consciousness, visual disturbance, unstable walking or fall. Common signs of posterior circulation ischemia: eye movement disorders, limb paralysis, sensory abnormalities, gait/limb ataxia, dysarthria/swallowing, visual field defects, hoarseness, Horner’s syndrome, etc. The presence of crossover manifestation of cerebral nerve damage on one side and motor-sensory damage on the other side is a characteristic manifestation of posterior circulation ischemia. 2. Common syndromes of posterior circulation ischemia Posterior circulation TIA, cerebellar infarction, lateral delayed brain syndrome, basilar artery acinar syndrome, weber syndrome, atresia syndrome, posterior cerebral artery infarction, lacunar infarction (motor mild hemiparesis, ataxia mild hemiparesis, dysarthria-clumsy hand syndrome, pure sensory stroke, etc.). A detailed history, physical examination and neurological examination are the basis for diagnosis. It is important to take a careful history, especially the onset, form, duration, concomitant symptoms, evolution and possible precipitating factors; to pay attention to various vascular risk factors; and to focus on the examination of cerebral nerves (vision, eye movements, facial sensation, hearing, vestibular function) and ataxia. In those with dizziness/vertigo as the main complaint, be sure to perform Dix-Hallpike examination to exclude benign episodic positional vertigo. Neuroimaging, mainly MRI, should be performed in all patients with suspected posterior circulation ischemia. DWI is most diagnostic for acute lesions. Cranial CT examination is susceptible to bone artifacts and has little diagnostic value, and is only applicable to exclude bleeding and patients who cannot enter MRI examination. Digital subtraction angiography, CT angiography, MRI angiography and vascular Doppler ultrasonography should be actively carried out to help detect and clarify large intracranial and extracranial vascular lesions. Each examination has its own characteristics, and there is a lack of correlation studies between different examinations. Transcranial Doppler ultrasonography (TCD) can detect stenosis or occlusion of the vertebral artery, but it cannot be the only basis for the diagnosis of posterior circulation ischemia. A variety of cardiac examinations can help to clarify embolism from the heart or aortic arch. Imaging of the cervical spine is not a preferred or important test.