The Collaborative International Dictionary of English v.0.48:

Inframaxillary \In`fra*max"il*la*ry\, a. [Infra + maxillary.]
   (Anat.)
   (a) Under the lower jaw; submaxillary; as, the inframaxillary
       nerve.
   (b) Of or pertaining to the lower iaw.
       [1913 Webster]

WordNet (r) 3.0 (2006):

inframaxillary
    adj 1: relating to the lower jaw [syn: mandibular,
           inframaxillary]