Hemiatrophy of the tongue and floor of the mouth demonstrated by computed tomography.

Computed tomography can show hemiatrophy of the tongue and the floor of the mouth. The normal neuroanatomy of this region with regard to its motor supply is reviewed. In theory six variants of motor nerve lesions with hemiatrophy can be encountered, three of which are illustrated in this report. Knowledge of the muscular anatomy and the motor nerve supply to the tongue and floor of the mouth is helpful when evaluating lesions of the base of the skull with CT. This is particularly true for the lesions involving the trigeminal and hypoglossal nerves.