The injection of a local anesthetic, such as lidocaine, results in the complete loss of sensation from well-defined areas of the face and mouth. For example, teeth on one side of the jaw can be numbed by injecting the mandibular nerve. Occasionally, injury or disease processes may affect two (or all three) branches of the trigeminal nerve; in these cases, the involved branches may be termed:  Nerves on the left side of the jaw slightly outnumber the nerves on the right side of the jaw. The ophthalmic, maxillary and mandibular branches leave the skull through three separate foramina: the superior orbital fissure, the foramen rotundum and the foramen ovale, respectively. The ophthalmic nerve (V1) carries sensory information from the scalp and forehead, the upper eyelid, the conjunctiva and cornea of the eye, the nose (including the tip of the nose, except alae nasi), the nasal mucosa, the frontal sinuses and parts of the meninges (the dura and blood vessels). The maxillary nerve (V2) carries sensory information from the lower eyelid and cheek, the nares and upper lip, the upper teeth and gums, the nasal mucosa, the palate and roof of the pharynx, the maxillary, ethmoid and sphenoid sinuses and parts of the meninges. The mandibular nerve (V3) carries sensory information from the lower lip, the lower teeth and gums, the chin and jaw (except the angle of the jaw, which is supplied by C2-C3), parts of the external ear and parts of the meninges. The mandibular nerve carries touch-position and pain-temperature sensations from the mouth. Although it does not carry taste sensation (the chorda tympani is responsible for taste), one of its branches—the lingual nerve—carries sensation from the tongue. The peripheral processes of mesencephalic nucleus of V neurons run in the motor root of the trigeminal nerve and terminate in the muscle spindles in the muscles of mastication. They are proprioceptive fibers, conveying information regarding the location of the masticatory muscles. The central processes of mesencephalic V neurons synapse in the motor nucleus V. The sensory function of the trigeminal nerve is to provide tactile, proprioceptive, and nociceptive afference to the face and mouth.