cerebellomedullary cistern cer·e·bell·o·med·ull·ar·y cistern (sěr'ə-běl'ō-měd'l-ěr'ē, mə-dŭl'ə-rē) n. The largest of the subarachnoid cisterns between the undersurface of the cerebellum and the dorsal surface of the medulla oblongata.
