spasmodic torticollis
noun [ U ] medical specialized uk/spæzˌmɒd.ɪk tɔː.tɪˈkɒl.ɪs/ us/spæzˌmɑː.dɪk ˌtɔːr.t̬ɪˈkɑː.lɪs/
痉挛性斜颈
a rare condition where the head moves from side to side and up and down due to spasms (= muscles suddenly becoming tighter in an uncontrolled way)