The Collaborative International Dictionary of English v.0.48:

Maxillo-palatine \Max*il`lo-pal"a*tine\, a. [Maxilla +
   palatine.] (Anat.)
   Pertaining to the maxillary and palatine regions of the
   skull; as, the maxillo-palatine process of the maxilla. Also
   used as n.
   [1913 Webster]