abnormal embryonic tissue morphology abnormal head mesenchyme morphology 2011-09-13T11:23:04Z MP:0011260 MPheno.ontology abnormal cephalic mesenchyme morphology abnormal cranial mesenchyme morphology any structural anomaly of the primordial embryonic connective tissue of the developing head, consisting of mesenchymal cells supported in interlaminar jelly, that derive mostly from the mesoderm and contribute to head connective tissue, bone and musculature in conjunction with cranial neural crest cells csmith abnormal head development