cerebellar ectopia
noun [ U ] medical specialized uk/ser.ɪˌbel.ər ekˈtəʊ.pi.ə/ us/ˌser.ɪˈbel.ɚ ekˈtoʊ.pi.ə/
小脑外疝
a condition in which part of the cerebellum (= the part of the brain that controls muscles, movement, and balance) pushes through a hole in the base of the skull