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Mandibular nerve


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Dental, Human anatomy, oral and maxillofacial surgery

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Mandibular nerve

  1. 1. Mandibular Nerve
  2. 2. Introduction • Its the largest branch of trigeminal nerve. It is a mixed nerve with two roots : – large sensory root – small motor root • The sensory root of the mandibular division originates at the inferior angle of the trigeminal ganglion • The motor arises in the motor cells located in the pons & medulla oblongata. • The two roots emerge from the cranium separately through the foramen ovale , the motor root lying medial to sensory . • They unite just outside the skull and form the main trunk of the third division . • This trunk remains undivided for only 2 to 3 mm before it splits into – a small anterior – a large posterior division
  3. 3. Root of Cranial Nerves
  4. 4. Mandibular Nerve: Supply • It supplies – the teeth and gums of the mandible, – the skin of the temporal region, – the auricula, – the lower lip, – the lower part of the face, – muscles of mastication; – it also supplies the mucous membrane of the anterior two-thirds of the tongue
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  6. 6. Branches from Undivided Nerve • NERVOUS SPINOSUS – It arises outside the skull – then passes into the middle cranial fossa to supply the dura & mastoid cells. • NERVE TO MEDIAL PTERYGOID MUSCLE – A branch of the motor root passes to innervate the medial pterygoid muscle. – This branch passes without interruption to inervate the tensor veli palatini and the tensor tympani muscles.
  7. 7. Anterior Division • Nerve to lateral pterygoid muscle:The pterygoid nerve enters the medial side of the lateral pterygoid muscle to provide its motor nerve supply. • Nerve to masseter muscle: the masseter nerve passes above the lateral pterygoid to transverse the mandibular notch. • Nerve to temporal muscles : its again divided in 2 branch – Anterior deep temporal nerve - It supplies deep part of the temporal the anterior portion of the temporal muscle. – Posterior deep temporal nerve- It passes upwards to the deep part of the temporal muscle.
  8. 8. Anterior Division • Long buccal nerve- it passes downward, anteriorly and laterally between the two heads of lateral pterygoid muscle. It supplies – Buccinator muscle – Mucous membrane of cheek
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  10. 10. POSTERIOR DIVISION • It is mainly sensory but also carries some motor components. This division extends downwards and medially and then branches into: – Auriculotemporal nerve – Lingual nerve – Inferior alveolar nerve
  11. 11. Auriculotemporal nerve • it arises by a medial and lateral root. • These roots embrance the middle meningeal artery and unite behind the artery just below the foramen spinosum. • It passes with superficial temporal artery in its upward course and divides into numerous branches – Tragus of the pinna of external ear , – Scalp about the ear – as far as upward as the vertex of the skull
  12. 12. Lingual nerve • It first passes medially to lateral pterygoid muscle • As it decends , lies between the internal pterygoid muscle and the ramus of the mandible. • The nerve lies parallel to the inferior alveolar nerve but medial and anterior to it . • It then passes deep to reach the side of the base of the tongue. • At the side of the tongue it lies below the lateral lingual sulcus. • It has communications with the chorda tympani of facial nerve
  13. 13. Inferior alveolar nerve • It is the largest branch of the posterior division of mandibular part of the trigeminal nerve. • It descends with the inferior alveolar artery, at first beneath the Pterygoideus plexus, • Then between the sphenomandibular ligament and the ramus of the mandible to the mandibular foramen. • It then passes forward in the mandibular canal, beneath the teeth, as far as the mental foramen, where it divides into two terminal branches, – incisive and mental. • The branches of the inferior alveolar nerve are the mylohyoid, dental, incisive, and mental.
  14. 14. Inferior alveolar nerve • Mylohyoid nerve – derived from the inferior alveolar just before it enters the mandibular foramen. – It descends in a groove on the deep surface of the ramus of the mandible, – Reaching the under surface of the Mylohyoideus supplies this muscle and the anterior belly of the digastric • Dental branches – Supply the molar and premolar teeth. – They correspond in number to the roots of those teeth; – each nerve entering the orifice at the point of the root, and supplying the pulp of the tooth; – above the alveolar nerve they form an inferior dental plexus. – This divideds in to 2 branch i.e incisive nerve and mental nerve
  15. 15. Inferior alveolar nerve • Incisive branch • Continuation of dental nerve - onward within the bone, and supplies the canine and incisor teeth • Mental nerve (n. mentalis) – Emerges at the mental foramen, – Divides beneath the Triangularis muscle into three branches; • one descends to the skin of the chin • two ascend to the skin and mucous membrane of the lower lip – These branches communicate freely with the facial nerve
  16. 16. Otic Ganglion (ganglion oticum) • The otic ganglion is a small, ovalshaped, flattened ganglion of a reddish-gray color, • Situated immediately below the foramen ovale; • Lies on the medial surface of the mandibular nerve, and surrounds the origin of the nerve to medial pterygoid • It is in relation, – Laterally, with the trunk of the mandibular nerve at the point where the motor and sensory roots join; – Medially, with the cartilaginous part of the auditory tube, and the origin of the Tensor veli palatini; – Posteriorly, with the middle meningeal artery.
  17. 17. Otic Ganglion • Peripheral parasympathetic ganglion which relays secretomotor fibers to the parotid gland • Its topographically related to mandibular gland but functionally part of glossopharyngeal nerve • Size : 2-3 mm in size
  18. 18. Otic Ganglion : Distribution • Motor and parasympathetic root – Formed by petrosal nerve – Preganglionic fibers – derived from inferior salivary nucleus of 9th nerve – Postganglionic fibers – pass through auricotemporal nerve to parotid gland • Sympathetic root – Plexus of middle meningeal artery – It contains postganglionic fibrs arising in the superior cervical ganglion – Fibers pass through the ganglion without relay and reach the parotid gland via auricotemporal nerve – They are vasomotor in function • Sensory root - auricotemporal nerve and its sensory to the parotid gland
  19. 19. Submandibular ganglion • Parasympathetic root – Preganglionic parasympathetic fibers from the facial nerve (CN VII) travel to the ganglion in the chorda tympani, facial nerve, and lingual nerve (CN V3). • Sympathetic root – Sympathetic fibers from the superior cervical ganglion ascend (via the internal carotid plexus) and travel in a plexus on the facial artery
  20. 20. References • Grays Anatomy for Students 2nd Edition • Head and Neck Anatomy for Dental Medicine • Head, Neck and Dental Anatomy, 4th Edition • Netter’s Head and Neck Anatomy for Dentistry, 2nd Edition Neil S norton