The Collaborative International Dictionary of English v.0.48:

Tympanic \Tym*pan"ic\ (?; 277), a. [See Tympanum.]
   1. Like a tympanum or drum; acting like a drumhead; as, a
      tympanic membrane.
      [1913 Webster]

   2. (Anat.) Of or pertaining to the tympanum.
      [1913 Webster]

   Tympanic bone (Anat.), a bone of the skull which incloses a
      part of the tympanum and supports the tympanic membrane.


   Tympanic membrane. (Anat.) See the Note under Ear.
      [1913 Webster]

WordNet (r) 3.0 (2006):

tympanic bone
    n 1: the bone enclosing the middle ear