The mandibular nerve is a nervous system vessel responsible for transmitting information between the lower face and jaw and the brain. A division of the larger trigeminal nerve, this nerve serves several of the muscles involved in chewing and speaking as well as the skin of the chin, bottom lip, inside of the cheek, and the temples. This means that it sends information in two directions: sensory input from the skin and mucous membranes is directed toward the brain, and motor signals from the brain are directed toward the muscles.
Branching off of the fifth cranial nerve, also called the trigeminal nerve, the mandibular nerve is situated entirely within the head. As the biggest of the 12 cranial nerves, the trigeminal nerve has three major branches: the ophthalmic, maxillary, and mandibular nerves. These split off the trigeminal nerve at roughly the height of the eye socket and deep to the ear, with the ophthalmic supplying sensation to the eye and forehead region, the maxillary providing sensation to the nasal and upper jaw region, and the mandibular transmitting sensation to the lower jaw and chin, to the mucous membranes of the tongue and inner check, to the sides of the face and temples, and to the muscles of these regions.
The mandibular nerve is largely a sensory vessel, meaning that is carries electrical signals from the skin and surfaces of other tissues to the brain. These signals, known as nerve impulses, communicate such sensory input as pain, pressure, and temperature. It also features a more minor motor division transporting nerve impulses in the other direction, signals from the brain telling the muscles of the face and jaw to produce chewing or speaking motions or to form expressions.
To accomplish these things, the mandibular nerve depends on multiple smaller branches. It is only a vessel of transport between these vessels and the trigeminal nerve. Examples of mandibular nerve branches include the medial pterygoid nerve, which supplies the pterygoid, a major muscle of chewing; the buccal nerve, which returns sensory information from the skin of the cheek and from the teeth, specifically the second and third molars; and the lingual nerve, which innervates the tongue.
Some of these branches, such as the medial pterygoid, split directly off the main trunk of the mandibular nerve. Most, however, occur after the nerve separates into its anterior and posterior sections, with the buccal, lateral pterygoid, masseteric, and temporal nerves found in the anterior division and the auriculotemporal, lingual, inferior alveolar, and myohyloid nerves branching off the posterior division.