An illusion of movement, either of the external world revolving around the individual or of the individual revolving in space. Vertigo may be associated with disorders of the inner ear (EAR, INNER); VESTIBULAR NERVE; BRAINSTEM; or CEREBRAL CORTEX. Lesions in the TEMPORAL LOBE and PARIETAL LOBE may be associated with FOCAL SEIZURES that may feature vertigo as an ictal manifestation. (From Adams et al., Principles of Neurology, 6th ed, pp300-1)

头眩，即眩晕，病证名，出自《金匮要略·中风历节病脉证并治》。

眩晕是因机体对空间定位障碍而产生的一种动性或位置性错觉，它涉及多个学科。绝大多数人一生中均经历此症。据统计，眩晕症占内科门诊病人的5%，占耳鼻咽喉科门诊的15%。眩晕可分为真性眩晕和假性眩晕。真性眩晕是由眼、本体觉或前庭系统疾病引起的，有明显的外物或自身旋转感。假性眩晕多由全身系统性疾病引起，如心血管疾病、脑血管疾病、贫血、尿毒症、药物中毒、内分泌疾病及神经官能症等几乎都有轻重不等的头晕症状，患者感觉“飘飘荡荡”，没有明确转动感。

Vertigo is a condition where a person has the sensation of movement or of surrounding objects moving when they are not. Often it feels like a spinning or swaying movement. This may be associated with nausea, vomiting, sweating, or difficulties walking. It is typically worse when the head is moved. Vertigo is the most common type of dizziness.