Disorders of the trigeminal system.

The management of patients with trigeminal system dysfunction requires an understanding of the system's complex anatomy, which extends from peripheral nerve endings, through the skull base, cavernous sinus (V1, V2 only), and trigeminal ganglion, to the intraaxial nuclei, tracts, and cerebral cortex. The differential diagnosis is broad. Seemingly minor facial sensory loss may indicate an underlying malignancy (as in numb-chin syndrome). Painful syndromes of the trigeminal nerve are numerous and require careful categorization. Understanding trigeminal system anatomy and the appropriate use of imaging and electrodiagnostics should aid in the diagnosis and treatment of these disorders.