Mandibular division:
Largest branch of the trigeminal nerve.
Mixed nerve with two roots: a large sensory root & smaller motor root.
Origin of roots:
Sensory root: origins at inferior angle of trigeminal ganglion.
Motor root: arises in motor cells located in pons and medulla oblongata.
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Sensory root |
Motor root |
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a.Skin Temporal region Auricular External auditory meatus Cheek Lower lip Lower part of face(chin region) b.Mucous membrane: Cheek Tongue (anterior two thirds) Mastoid cells c. Mandibular teeth and periodontal tissue. d. Bone of mandible e. Temporomandibular joint f. Parotid gland. |
a. Masticatory muscles. Masseter Temporalis Pterygoideus medialis Pterygoideus lateralis b. Mylohyoid c. Anterior belly of the digastric. d. Tensor tympani. e. Tensor veli palatini. |
Branches:
It gives off branches in three area: Undivided nerve, anterior and posterior division.
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Undivided nerve |
Divided nerve |
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a. Nervus spinosus b. Nerve to medial pterygoid muscle. |
a. anterior division: nerve to the
lateral pterygoid muscle masseter
muscle, temporal muscle, buccal nerve. b. posterior division: auriculotemporal nerve Lingual nerve Mylohyoid nerve Inferior alveolar nerve:dental branches Incisive branch: dental branches. Mental nerve. |
Undivided nerve:
It gives off two branches.
- Nervous spinosus.[meningeal branch of mandibular nerve]
- Medial pterygoid nerve.
Nervous spinosus:
Enters cranium through foramen spinosum along with middle meningeal artery to supply the duramater & mastoid air cells.
Medial pterygoid nerve:
It is motor nerve to medial(internal) pteygoid muscle.
Supply motor branch to tensor vali palatini & tensor tympani.
Anterior division:
Branches of these will provide-
- Motor innervation to muscles of mastication.
- Sensory innervation to mucous membrane cheek & buccal mucous membrane of mandibular molar.
Course:
Under lateral pterygoid, it gives off several branches:
👉Deep temporal nerve [ to temporal muscle ]
👉Masseter nerve.
👉Lateral pterygoid nerve.
Buccal nerve:
Also known as buccinator nerve and long buccal nerve, usually passes between two heads of lateral pterygoid to reach external surface of muscle.
It then follows inferior part of temporal muscle & emerges under the anterior border of masseter muscle, continuing in anterolateral direction.
At level of occlusal plane of mandiblular 3rd or 2nd molar, it crosses in front of anterior border of ramus, & enters the cheek through buccinator muscle.[here sensory fibre distributes to skin of cheek].
Other fibre passes into retromolar triangle, providing sensory innervation to buccal gingiva of mandibular molars & mucobuccal fold in that region.
Posterior division:
Primarily sensory with small motor component.
It descends for short distance downward & medially to lateral pterygoid muscle, at which point it branches into:
- Auriculotemporal nerve
- Lingual nerve
- Inferior alveolar nerve.
Auriculotemporal nerve:
Traverse the upper part of parotid gland & crosses posterior portion of zygomatic arch.
⧭ All of its branches are sensory.
⧭Provides sensory fibre to skin over the area of innervation of motor branches of facial nerve:
Zygomatic, buccal, mandibular- communicates with otic ganglion, providing sensory, secretory & vasomotor fibre to the parotid gland.
Anterior auricular branches- supply skin over helix and tragus of ears.
Branches to external auditory meatus- innervating skin over meatus & tympanic membrane.
Articular branches- to posterior portion of TMJ.
Superficial temporal- supply skin over temporal region.
Lingual nerve:
2nd branch of posterior division.
Course:
- Passes downward medial to the lateral pterygoid muscle, lies between ramus & medial pterygoid muscle in pterygomandibular space.
- Runs anterior & medial to inferior alveolar nerve.
- Continues downward & forward deep to pterygomandibular raphae, below attachment of superior constrictor of pharynx, to reach side of base of tongue slightly below and behind mandibular 3rd molar.[here it lies just below mucous membrane in the lateral lingual sulcus].
- It then proceeds anteriorly across muscle of tongue, looping downward & medial to submandibular (wharton's) duct to deep surface of sublingual gland where it breaks up into its terminal branches.
Provide both general sensation & gustation (taste) to this region.
It also provide sensory innervation to mucous membrane of floor of mouth & gingiva on the lingual side of mandible.
Inferior alveolar nerve:
Largest branch of mandibular division.
Course: Descends medial to lateral pterygoid muscle & lateroposterior to lingual nerve, to the region between sphenomandibular ligament & medial surface of mandibular ramus, it enters mandibular canal at the level of mandibular foramen.
Throughout its path, it is accompanied by inferior alveolar artery & vein.
Nerve, artery and vein travels anteriorly in mandibular canal, towards mental foramen, it divides into terminal branches- Incisive nerve, & mental nerve.
Mylohyoid nerve:Mixed nerve, branch from Inferior Alveolar Nerve.
Before entry into mandibular canal - It runs downward & forward in mylohyoid groove on medial surface of ramus, and along body of mandible to reach mylohyoid muscle.
- Motor divison- mylohyoid muscle & anterior belly of digastric muscle.
- Sensory- skin on inferior & anterior surface of mental protuberance, mandibular incisor.
Incisive nerve:
Remains within mandibular canal, for nerve plexus that innervate pulpal tissue of mandibular 1st premolar, canine, incisors via dental branches.
Mental nerve:
Exit canal, through mental foramen, & divides into 3 branches- innervate skin of chin, skin & mucous membrane of lip.
Clinical anatomy:
Damage to mandibular nerve will cause loss of jaw reflex.
Flaccid paralysis of muscles of mastication in injury of mandibular nerve leading to decrease strength of bite.
Hypoacusis: partial deafness to loew pitched sounds due to paralysis of tensor tympani muscle.
Trigeminal neuralgia: Principal disease affecting sensory root of V nerve is characterized by attacks of severe pain in the area of distribution of maxillary or mandibular divisions. (maxillary nerve is most frequently involved).
Check below link for:Trigeminal nerve ophthalmic division, origin, branches-
Maxillary division, origin, branches - https://www.blogger.com/blog/post/edit/4923003805564511941/7976023347950395136
Development, histology and clinical anatomy of tongue-
Muscles of tongue [why can't you swallow the tongue itself😂]-
or mail me at yatamsaraswathi@gmail.com
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