phrenograph

from The Collaborative International Dictionary of English v.0.48

Phrenograph \Phre"no*graph\ (fr[=e]"n[-o]*gr[.a]f), n. [Gr.
   frh`n, freno`s, the midriff + -graph.] (Physiol.)
   An instrument for registering the movements of the diaphragm,
   or midriff, in respiration.
   [1913 Webster]