Walsh & Hoyt: Involvement of the Gasserian Ganglion or the Sensory Root of the Trigeminal Nerve

Paralytic lesions of the gasserian ganglion, whether ischemic, inflammatory, compressive, traumatic, toxic, or infiltrative, cannot be differentiated dependably from lesions of the sensory root. Involvement of both structures may cause anesthesia in one or more divisions of the trigeminal nerve as well as paralysis of the motor nerve to the muscles of mastication. Certain findings may help, however, to differentiate a lesion in the region of the cavernous sinus, involving the ganglion or root, from focal involvement of the sensory root in the perimesencephalic cistern. A trigeminal deficit associated with ophthalmoplegia usually indicates a lesion of the cavernous sinus or Meckels cave. In the absence of a more peripheral lesion, sensory loss limited to the ophthalmic distribution signifies a lesion of the cavernous sinus or superior orbital fissure, as does the associated finding of paralysis of the ipsilateral oculosympathetic nerve. On the other hand, loss of facial or corneal sensation combined with paralysis of the facial and auditory nerves implies involvement of the sensory root in the basal cistern (e.g., as in the syndrome of the cerebellopontine angle)