The trigeminal nerve is the largest cranial nerve, serving as a major conduit for sensory information from the head and neck and primarily providing motor innervation to the muscles of mastication.An understanding of the pathologic processes that may involve the nerve requires a detailed knowledge of its origin within the brainstem as well as its course intracranially.The trigeminal nerve is described in terms of segmental anatomy and regional pathology. The common brain stem lesions are neoplasms, vascular disease, and demyelinating processes. Common lesions affecting the cisternal segment and Meckel’s cave are schwannomas, meningiomas, epidermoid cysts, vascular ectasia and aneurysms. Common lesions affecting the cavernous segment include meningioma, trigeminal schwannoma, lymphoma, metastasis, and vascular lesions. Skull base lesions that can affect the course of the trigeminal nerve include chordoma, chondrosarcoma, metastasis, bone dysplasias, and paget’s disease. The peripheral divisions of the trigeminal nerve are commonly involved by adjacent inflammatory disease in the sinuses, perineural spread of malignancy, and schwannomas.Trigeminal neuropathy refers to the prescence of a trigeminal nerve sensory or motor deficit, including numbness, paresthesias, atrophy of the masticatory muscles or trismus. Magnetic resonance imaging is the imaging modality of choice when trigeminal nerve pathology is suspected. Most lesions are readily recognizable on Magnetic resonance imaging if appropriate imaging sequences are performed. Magnetic resonance imaging is useful in planning the management of those conditions where surgical or medical intervention can result in improvement or resolution of symptoms. Intravenous gadolinium-DTPA often provides additional diagnostic information.