The Mandibular Nerve: The Anatomy of Nerve Injury and Entrapment

The trigeminal nerve (TN) is a mixed cranial nerve that consists primarily of sensory neurons. It exists the brain on the lateral surface of the pons, entering the trigeminal ganglion (TGG) after a few millimeters, followed by an extensive series of divisions. Of the three major branches that emerge from the TGG, the mandibular nerve (MN) comprises the 3rd and largest of the three divisions. The MN also has an additional motor component, which may run in a separate facial compartment. Thus, unlike the other two TN divisions, which convey afferent fibers, the MN also contains motor or efferent fibers to innervate the muscles that are attached to mandible (muscles of mastication, the mylohyoid, the anterior belly of the digastric muscle, the tensor veli palatini, and tensor tympani muscle). Most of these fibers travel directly to their target tissues. Sensory axons innervate skin on the lateral side of the head, tongue, and mucosal wall of the oral cavity. Some sensory axons enter the mandible to innervate the teeth and emerge from the mental foramen to innervate the skin of the lower jaw.