Embedded Files
6. What are the main branches of V3 (mandibular n.) when considering mastication, and what do they innervate? Which branches are affected by an inferior alveolar nerve block?
6. What are the main branches of V3 (mandibular n.) when considering mastication, and what do they innervate? Which branches are affected by an inferior alveolar nerve block?
The mandibular n. (V3) is a division of the trigeminal n. (CN V) and exits the cranial cavity through the foramen ovale of the sphenoid bone into the infratemporal fossa. It consists of a main trunk, an anterior division, and a larger posterior division. V3 serves several important functions, chiefly: efferent to muscles of mastication and afferent to mandible, mandibular teeth & gingiva, and skin superficial to a portion of the temporal region. V3 is one of the deepest structures in the infratemporal fossa. Branches of V3 will often accompany similarly named branches of the maxillary a., and may be located concurrently.
Trunk of mandibular n. (V3):
Nerve to medial pterygoid - efferent innervation to medial pterygoid m.
Anterior division of mandibular n. (V3):
Masseteric n. - efferent innervation to masseter m.
Deep temporal n. - efferent innervation to temporalis m,; variable number of branches
Nerve to lateral pterygoid - efferent innervation to lateral pterygoid m.; typically a branch of the buccal n.
Buccal n. (long buccal n.) - afferent innervation to skin overlying buccinator and buccal mucous membrane; can be located passing between the two heads of the lateral pterygoid m.
Posterior division of mandibular n. (V3):
Auriculotemporal n. - afferent innervation to TMJ, to a portion of the skin of external acoustic meatus, to the skin of the anterior auricle of the ear, and to the skin of the superior V3 dermatome (anterior and anterosuperior to the ear)
Postganglionic parasympathetic fibers from the otic ganglion travel with the auriculotemporal n. to the parotid gland
Lingual n. - afferent innervation to presulcal part (anterior 2/3rds, excepting vallate papillae) of the tongue and the mucosa of the floor of the oral cavity
Joined by the chorda tympani in the infratemporal fossa
Inferior alveolar n. - afferent innervation via branches to all mandibular teeth and gingiva
Gives off nerve to mylohyoid; enters the mandibular foramen
Forms inferior dental plexus and 2 terminal branches: incisive br. and mental n.
Anesthetic may be injected around the vicinity of the mandibular foramen in a procedure known as an inferior alveolar nerve block. When correctly performed, all mandibular teeth on the ipsilateral side of the mandible are anesthetized, in addition to skin of lower lip and chin, gingivae, and mucosa associated with the lower lip and mandibular teeth (afferent innervation from branches of inferior alveolar n.). Issues may arise if injection of anesthetic occurs in structures adjacent to the mandibular foramen, such as the medial pterygoid m. or parotid gland.
Report abuse