Mandibular nerve

INTRODUCTION:
  • Largest of the three divisions of the fifth cranial nerve
  • Made up of two roots:
  • A large - sensory root proceeding from the inferior angle of the semilunar ganglion.
  • A small motor root which passes beneath the ganglion unites with the sensory root just after it exit foramen ovale.
  • It exits skull from foramen ovale
  • Immediately beneath the base of the skull gives off a recurrent branch (nervous spinosus) and the nerve to the Pterygoideus internus then divides into two trunks an anterior and a posterior.
SUPPLIES:
  • Teeth and gums of the mandible.
  • The skin of the temporal region
  • The auricle. 
  • The lower lip. 
  • The lower part of the face. 
  • The muscles of mastication.
  • It also supplies the mucous membrane of the anterior two-thirds of the tongue. 
  • Middle cranial fossa is supplied by maxillary and mandibular nerve
BRANCHES:
  • Main trunk
  1. Medial pterygoid
  2. Nervous spinosus (meningeal branch)enters the skull through foramen spinosum. Supplies duramatter of middle cranial fossa.
  3. Nerve to tensor veli palatine.
  4. Nerve to tensor tympani
  5. Anterior division
  6. The anterior and smaller division of the Mandibular nerve receives nearly the whole of the fibers of the motor root of the nerve.
  • Supplies Muscles of mastication mylohyoid, anterior belly of digastric,medial pterygoid , tensor tympani and tensor veli palatini & Skin and mucous membrane of the cheek Massetric 
Arises from the upper border of lateral pterygoid muscle.
Passes through Mandibular notch.
Enters the deep part of masseter.
Also supplies TMJ (temporomandibular joint).
  • External Pterygoid
Arises in conjunction with the Buccinator nerve.
But may be given off separately from the anterior division of the Mandibular nerve.
It enters the deep surface of the muscle.
  • Deep Temporal
2 Nerve anterior and posterior.
Passes btn skull and lateral pterygoid.
Enters the deep surface of temporalis muscle.
  • Buccinators
Only sensory branch from anterior division.
Passes between 2 heads of lateral pterygoid.
Supplies skin and mucous membrane related to Buccinator.
  • Posterior division
  • The posterior and larger division of the Mandibular nerve sensory but receives a few filaments from the motor root
  • Auriculotemoral 
  1. Arises by two roots b/w which the middle meningeal artery ascends.Runs backward beneath to the medial side of the neck of the mandible.Then turns upward with the superficial temporal artery b/w the auricule and condyle of the mandible. It ascends over Zygomatic arch divides into superficial temporal branches. Supplies external acoustic meatus, external surface of auricle above this, skin of temporal region and TM joint.
  • Lingual
  1. Supplies - mucous membrane of the anterior two-thirds of the tongue.
  2. Lies at first beneath the lateral Pterygoid - medial to and in front of the inferior alveolar nerve.
  3. The nerve then passes b/w the medial Pterygoideus and the ramus of the mandible then between the Hyoglossus and deep part of the submaxillary gland.
  4. Finally runs across the duct of the submaxillary gland and along the tongue to its tip.
BRANCHES OF DISTRIBUTION: 
  • Supply
  1. Mucous membrane of the mouth, the gums, and the anterior two-thirds of the tongue.
  2. The terminal filaments communicate at the tip of the tongue with the hypoglossal nerve.
  • Inferior alveolar 
  1. Largest branch of the Mandibular nerve.
  2. Descends with the inferior alveolar artery at first beneath the lateral Pterygoid then b/w the sphenomandibular ligament and the ramus of the mandible to the Mandibular foramen.
  3. 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.
  4. Branches of the inferior alveolar nerve are :
  • Mylohyoid
  1. Derived from inferior alveolar just before it enters the mandibular foramen.
  2. It descends groove on the deep surface of the ramus of the mandible reaching the under surface of the Mylohyoid supplies this muscle and the anterior belly of the Digastric.
  3. Dental
  4. Supply m
  5. olar and premolar teeth
  6. Above the alveolar nerve they form an inferior dental plexus. 
  7. Incisive 
  8. Continued onward within the bone and supplies the canine and incisor teeth.
  • Mental 
  1. Emerges at the mental foramen divides beneath the Triangularis muscle into three branches.
  2. One descends to the skin of the chin.
  3. Two ascend to the skin and mucous membrane of the lower lip.
  4. These branches communicate freely with the facial nerve.
Exam Question
  • Mandibular nerve exits skull from foramen ovale
  • Middle cranial fossa is supplied by maxillary and mandibular nerve
  • Nervous spinosus (meningeal branch)enters the skull through foramen spinosum.
  • Anterior division of mandibular nerve supplies Muscles of mastication mylohyoid, anterior belly of digastric,medial pterygoid , tensor tympani and tensor veli palatini & Skin and mucous membrane of the cheek
  • Anterior division of mandibular nerve have 4 branches Massetric,External Pterygoid, Deep Temporal & Buccinators
  • Lingual nerve runs across the duct of the submaxillary gland

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