Mandibular nerve
MANDIBULAR NERVE
The mandibular nerve is the largest mixed branch of the trigeminal nerve.
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Mandibular Nerve
- The mandibular nerve is the largest mixed branch of the trigeminal nerve.
- It is the nerve of the 1st branchial arch.
- It supplies all structures derived from the 1st branchial arch.
- Otic and submandibular ganglia are associated with this nerve.
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Course and Relations
Beginning
Mandibular nerve begins in the middle cranial fossa through:
- A large sensory root
- A small motor root
Sensory Root
- Arises from the lateral part of trigeminal ganglion.
- Leaves the cranial cavity through the foramen ovale.
Motor Root
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Lies deep to:
- Trigeminal ganglion
- Sensory root
- Passes through the foramen ovale.
- Joins the sensory root just below the foramen.
- Thus, it forms the main trunk.
Main Trunk
- Lies in the infratemporal fossa.
- Lies on the tensor veli palatini.
- Lies deep to the lateral pterygoid.
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After a short course, the main trunk divides into:
- A small anterior trunk
- A large posterior trunk
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Branches of Mandibular Nerve
From Main Trunk
1. Meningeal branch
2. Nerve to medial pterygoid
From Anterior Trunk
Sensory Branch
1. Buccal nerve
Motor Branches
- Masseteric nerve
- Deep temporal nerves
- Nerve to lateral pterygoid
From Posterior Trunk
1. Auriculotemporal nerve
2. Lingual nerve
3. Inferior alveolar nerve
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Meningeal Branch / Nervus Spinosus
- Enters the skull through the foramen spinosum along with the middle meningeal artery.
- Supplies the dura mater of the middle cranial fossa.
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Nerve to Medial Pterygoid
- Arises close to the otic ganglion.
- Supplies the medial pterygoid from its deep surface.
- Gives a motor root to the otic ganglion.
- This motor root does not relay.
Supply
- Tensor veli palatini
- Tensor tympani muscles
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Buccal Nerve
It is the only sensory branch of the anterior division of the mandibular nerve.
Course
- Passes between the two heads of lateral pterygoid.
- Runs downwards and forwards.
Supply
- Skin of cheek
- Mucous membrane related to buccinator
- Labial aspect of gums of molar and premolar teeth.
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Masseteric Nerve
- Emerges at the upper border of lateral pterygoid, just in front of the temporomandibular joint.
- Passes laterally through the mandibular notch along with the masseteric vessels.
- Enters the deep surface of masseter.
- Also supplies the temporomandibular joint.
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Deep Temporal Nerves
1. Anterior
2. Posterior
Course
- They pass between the skull and lateral pterygoid.
- Enter the deep surface of temporalis.
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Nerve to Lateral Pterygoid
Enters the deep surface of the muscle.
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Auriculotemporal Nerve
Formation
- Arises by two roots.
- The two roots run backwards and encircle the middle meningeal artery.
- They unite to form a single trunk.
Course
-
Continues backwards between:
- Neck of mandible
- Sphenomandibular ligament
- Lies above the maxillary artery.
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Behind the neck of mandible:
- Turns upwards.
- Ascends on the temple behind the superficial temporal vessels.
Distribution
1. Auricular Part
Supplies the skin of:
- Tragus
- Upper parts of pinna
- External acoustic meatus
- Tympanic membrane
Note
Lower parts of these regions are supplied by:
- Great auricular nerve
- Auricular branch of vagus nerve
2. Temporal Part
Supplies the skin of temple.
Other Supply
Auriculotemporal nerve also supplies:
-
Parotid gland
- Secretomotor
- Sensory
- Temporomandibular joint.
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Lingual Nerve
Lingual nerve is a branch of the posterior division of mandibular nerve.
Course
- Begins 1 cm below the skull.
- About 2 cm below the skull, it is joined by the chorda tympani nerve at an acute angle.
- Then it lies in contact with the mandible, medial to the 3rd molar tooth.
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Finally, it lies on the surface of:
- Hyoglossus
- Genioglossus
- Reaches the tongue.
Relations
- Begins 1 cm below the skull.
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First runs between:
- Tensor veli palatini
- Lateral pterygoid
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Then runs between:
- Lateral pterygoid
- Medial pterygoid
- About 2 cm below the skull, it is joined by the chorda tympani nerve.
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At the lower border of lateral pterygoid, it emerges and runs:
- Downwards
- Forwards
- Runs between ramus of mandible and medial pterygoid.
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Next, it lies in direct contact with the mandible, medial to the 3rd molar tooth, between the origins of:
- Superior constrictor
- Mylohyoid
- It soon leaves the gum and runs over the hyoglossus, deep to the mylohyoid.
- Finally, it lies on the surface of genioglossus, deep to the mylohyoid.
- Here it winds around the submandibular duct and divides into its terminal branches.
Distribution
It is sensory to:
- Anterior 2/3rd of tongue
- Floor of mouth
Fibres of Chorda Tympani
- Fibres of the chorda tympani (branch of facial nerve) are also distributed through the lingual nerve.
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Chorda tympani fibres are:
- Secretomotor to submandibular and sublingual salivary glands.
- Gustatory to anterior 2/3rd of tongue.
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Inferior Alveolar Nerve
- It is the larger terminal branch of the posterior division of mandibular nerve.
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Runs vertically downwards:
- Lateral to the medial pterygoid
- Lateral to the sphenomandibular ligament
- Enters the mandibular foramen.
- Runs in the mandibular canal.
- It is accompanied by the inferior alveolar artery.
Branches
1. Mylohyoid Branch
- Contains all the motor fibres of the posterior division.
- Arises just before the inferior alveolar nerve enters the mandibular foramen.
- Pierces the sphenomandibular ligament with the mylohyoid artery.
- Runs in the mylohyoid groove.
Supplies:
- Mylohyoid muscle
- Anterior belly of digastric
2. Branches to Lower Teeth and Gums
While running in the mandibular canal, the inferior alveolar nerve gives branches supplying the lower teeth and gums.
3. Mental Nerve
- Emerges at the mental foramen.
Supplies:
- Skin of chin
- Skin and mucous membrane of lower lip.
4. Incisive Branch
Supplies the labial aspect of gums of canine and incisor teeth.