tegmen tym·pa·ni -'tim-pə-.nī n a thin plate of bone that covers the middle ear and separates it from the cranial cavity
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[TA] roof of tympanum: the thin layer of translucent bone, on the petrous part of the temporal bone in the floor of the middle cranial fossa, separating the epitympanum from the cranial cavity; see also paries tegmentalis cavitatis tympani.Medical dictionary. 2011.