tribasilar synostosis

tri·bas·i·lar syn·os·to·sis

fusion in early life of the three bones at the base of the skull, resulting in interference with the development of the brain.
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tribasilar synostosis

A condition resulting from the premature fusion of three skull bones—the occipital, sphenoid, and temporal. This results in arrested cerebral development and mental deficiency.
Medical Dictionary, © 2009 Farlex and Partners