Relating to the tympanic cavity and the mastoid cells. ... (05 Mar 2000) ... 
Type: Term Pronunciation: tim′pă-nō-mas′toyd Definitions: 1. Relating to the tympanic cavity and the mastoid process.
tympanomastoid Relating to the tympanic cavity (air chamber in the temporal bone containing the ossicles or small bones of the middle ear) and the mastoid cells (small intercommunicating cavities in the mastoid process or a nipple-like projection).