The Collaborative International Dictionary of English v.0.48:

Exstrophy \Ex"stro*phy\, n. [Gr. ? to turn inside out; ? = ? out
   + ? to turn.] (Med.)
   The eversion or turning out of any organ, or of its inner
   surface; as, exstrophy of the eyelid or of the bladder.
   [1913 Webster]