The Collaborative International Dictionary of English v.0.48:

Tympanohyal \Tym`pa*no*hy"al\, a. (Anat.)
   Of or pertaining to the tympanum and the hyoidean arch. -- n.
   The proximal segment in the hyoidean arch, becoming a part of
   the styloid process of the temporal bone in adult man.
   [1913 Webster]