本文报告3例不伴随颅底压迹,开始怀疑肌蒌缩侧索硬化(ALS)、脊延髓空洞症、多发性硬化、最后经MRI检查肯定为Arnold—Chiari畸形。例1:男,40岁。20年来左下肢力弱,但未发展。1972年曾被诊断“运动神经元疾病”。近半年出现4次头晕,每在低头或转头时出现,持续数秒钟。查体:智力好。左侧上、下肢发育较对侧差。四肢肌力Ⅴ级,左上肢肌张力增强,左上肢比对侧细2.5～3.0cm,下肢细5cm,左侧手和足均小于右侧。四肢肌腱反射亢进,左踝阵挛+。双侧病理反射(+),无感觉障碍。共济检查正常。行走呈痉挛步态。腰穿压力1.86kPa,压颈试验通畅,CSF蛋白1.63g/L。颈椎片:见2—4颈椎骨质增生。椎间孔变窄,颅颈交界侧位片未见骨畸形。颈椎CT3—5椎管狭窄(前后径1～1.1cm):头颅CT为梗阻性脑积水。头颅MRI示延髓下段及小脑扁桃体下疝、脑积水。例2:男,33岁。4年前左半身多汗,半年后变为 This report reported three cases without skull base atherosclerosis, began to suspect muscular contralateral lateral sclerosis (ALS), spinal pubbar syringomyelia, multiple sclerosis, and finally confirmed by MRI Arnold-Chiari deformity. Example 1: Male, 40 years old. Left lower limb weak for 20 years, but no development. 1972 was diagnosed as “motor neuron disease.” In the past six months, 4 dizziness occurred, each time you bow or turn around, for a few seconds. Physical examination: good intelligence. On the left, lower limb development than the contralateral. Limb muscle strength Ⅴ level, left upper limb muscle tension increased, the left upper limb than the contralateral fine 2.5 ~ 3.0cm, lower extremity thin 5cm, left hand and foot are less than the right. Extremity tendon hyperreflexia, left ankle clonus +. Bilateral pathological reflex (+), no sensory disturbances. Masonic check normal. Walking was spastic gait. Waist wear pressure 1.86kPa, pressure neck test unobstructed, CSF protein 1.63g / L. Cervical spondylosis: see 2-4 cervical hyperostosis. Intervertebral foramen narrowing, cranial neck junction film no bone deformity. Cervical CT3-5 spinal stenosis (anteroposterior diameter of 1 ~ 1.1cm): head CT for obstructive hydrocephalus. Head MRI shows the inferior medulla oblongata and cerebellar tonsil hernias, hydrocephalus. Example 2: Male, 33 years old. 4 years ago, the left half sweat, six months later became