Damage to the angular gyrus includes four symptom clusters, including finger loss, inability to calculate, inability to write, and left-right disorientation. Angular gyrus lesions in the parietal and temporal lobes of the main hemisphere, with occlusion of the posterior parietal artery or angular gyrus artery, are common. It can also be seen in brain tumors, traumatic brain injury, brain atrophy, alcoholism, carbon monoxide poisoning, various psychiatric disorders, and hypnagogic states. Such as cerebral arteriosclerosis, stroke, and cerebrovascular malformation. Clinical examination methods are as follows. 1, head CT: head CT is simple, quick, and can clearly diagnose many problems of traumatic brain injury. Such as brain contusion, cerebral contusion, intracerebral hematoma, traumatic subarachnoid hemorrhage, skull fracture, etc. CT can also be used for dynamic observation after trauma to understand the recovery situation. 2, magnetic resonance imaging (MRI) of the head: MRI is an important supplement to CT of the head, and has better results for some special injuries, such as contusions of the brainstem and posterior cranial fossa, contusions of the corpus callosum, and diffuse axonal injuries, which may manifest as prolonged primary coma, but the CT of the head may behave normally, and on MRI, especially magnetic susceptibility imaging, there are often exact abnormalities that can be clearly diagnosed. Magnetic susceptibility imaging is now indispensable as a routine test for traumatic brain injury in the United States.