患者男，３１岁，头部外伤一天行ＣＴ检查。既往曾有左枕部间歇性疼痛史３～４年。 ＣＴ表现：左枕骨见约２．５ｃｍ×１．５ｃｍ × ３ｃｍ大小之骨性高密度影向颅内突起，其基底部与颅内板无明显分界，病灶中央见小片状略低密度区（附图）。 手术及病理所见：左枕部硬膜下见 Patient Male, 31 years old, head CT one day after trauma. Past history of the left occipital intermittent pain history of 3 to 4 years. CT manifestations: see the left occipital bone size of about 2.5cm × 1.5cm × 3cm bony high-density shadow of the intracranial processes, the basal and intracranial plate no obvious delineation of the lesion to see a small piece of slightly lower density area ( Drawing). Surgical and pathological findings: see the left occipital subdural