Takano M, Aoki K
Department of Neurology, Toyama Prefectual Central Hospital.
Rinsho Shinkeigaku. 2000 Aug;40(8):832-5.
We presented a patient of isolated inferior rectus muscle palsy from midbrain lacunar infarction involving the oculomotor nucleus. The patient noticed sudden onset diplopia gazing to the right side, especially to the right-lower direction. He did not have any other symptom, and neurological examination revealed no other findings. Brain MRI documented the focal hyperintense lesion on T2-weighted images in the right-median midbrain ventral to the aqueduct at the level of the superior colliculus. This lesion involved the right oculomotor nucleus, especially the dorso-lateral subnucleus extend to the inferior rectus muscle. The oculomotor nuclear complex consists of one unpaired subnucleus and four paired subnuclei. Among them, the inferior rectus subnucleus lies dorso-laterally. So nucleus lesion may cause isolated weakness of one of muscles innervated by the oculomotor nerve. Among them the isolated inferior rectus muscle palsy can occur relatively.
我们报告了一例因中脑腔隙性梗死累及动眼神经核导致单纯性下直肌麻痹的患者。患者在向右注视，尤其是向右下方注视时突然出现复视。他没有任何其他症状，神经学检查也未发现其他异常。脑部磁共振成像（MRI）显示，在中脑上丘水平导水管腹侧右侧正中区域的T2加权图像上有局灶性高信号病变。该病变累及右侧动眼神经核，尤其是背外侧亚核延伸至下直肌。动眼神经核复合体由一个不成对亚核和四个成对亚核组成。其中，下直肌亚核位于背外侧。因此，核病变可能导致动眼神经支配的某一块肌肉出现单纯性无力。其中，单纯性下直肌麻痹相对较为常见。
