The word "ptomatopsy" is not a commonly known word, but it is a real medical term referring to the examination of the mouth using a light. The spelling of this word follows the Greek origin of the term. The "p" is silent, and the "t" is pronounced as "d" because of its placement after "p". The "o" is pronounced as "ah" and the "a" as "uh". The "ps" is pronounced with a "p" and "s" sound together. Thus, "ptomatopsy" is pronounced as "do-ma-tahp-see".
Inspection of a dead body; autopsy.
A practical medical dictionary. By Stedman, Thomas Lathrop. Published 1920.