Trigeminal Nerve
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Transcript of Trigeminal Nerve
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Trigeminal Nerve
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Trigeminal nerve• Largest & one of most
complex cranial nerves• Mixed nerve• Large sensory part & much
smaller motor part• Sensory component has 3
divisions : ophthalmic, maxillary, mandibular.
• Motor & prinicipal sensory nuclei – midpons
• Spinal tract & nucleus (pain, temp) – pons to upper cervical cord
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TRIGEMINAL NERVE
Type: Mixed (sensory & motor).
Fibers:1. General somatic
afferent: Carrying general
sensations from face.2. Special visceral
efferent: Supplying muscles
developed from the 1st pharyngeal arch, (8 muscles).
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TRIGEMINAL NERVE NUCLEI
Four nuclei: (3 sensory + 1 Motor). General somatic afferent:1. Mesencephalic (midbrain & pons):
receives proprioceptive fibers from face.
2. Principal (main) sensory (pons): receives touch fibers from face.
3. Spinal (pons, medulla & upper 2-3 cervical segments of spinal cord): receives pain & temperature sensations from face.
Special visceral efferent:4. Motor nucleus (pons): supplies: Four Muscles of mastication
(temporalis, masseter, medial & lateral pterygoid).
Other four muscles (Anterior belly of digastric, mylohyoid, tensor tympani & tensor palati).
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TRIGEMINAL GANGLION
Site: Occupies a depression
in the middle cranial fossa.
Importance: Contains cell bodies:
1. Whose dendrites carry sensations from the face.
2. Whose axons form the sensory root of trigeminal nerve.
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TRIGEMINAL NERVE
Emerge from middle of the ventral surface of the pons by 2 roots (large lateral sensory root & small medial motor root).
Divides into 3 divisions (dendrites of trigeminal ganglion):
1. Ophthalmic.2. Maxillary.3. Mandibular. Axons of cells of motor
nucleus join only the mandibular division.
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Pure Sensory
Pure Sensory
Mixed Nerve
C2,3Great
auricular N.
Areas of Distribution of Trigeminal Nerve in the Face
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OPHTHALMIC (PURE SENSORY)
Divides into:3 branches:
frontal, lacrimal & nasociliary which pass through superior orbital fissure to orbit.
1. Frontal: supplies skin of face & scalp.
2. Lacrimal: supplies skin of face & lacrimal gland.
3. Nasociliary: supplies skin of face, nasal cavity & eyeball.
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MAXILLARY (PURE SENSORY)
Supplies:1. Upper teeth,
gums & maxillary air sinus:
(posterior, middle & anterior superior alveolar nerves).
2. Face: (zygomaticofacial ,zygomatico temporal &infraorbital nerves).
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MANDIBULAR (MIXED)
SENSORY BRANCHES:1. Lingual: General sensations from
anterior 2/3 the of tongue.2. Inferior alveolar: Lower teeth, gums & face.3. Buccal: Face(cheek on upper jaw)
4. Auriculotemporal: auricle, temple, parotid gland
& TMJ. MOTOR BRANCHES: to 8 muscles ( 4 muscles of
mastication & other 4 muscles).
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Muscles of Mastication
• Masseter : close the jaw , protrude it slightly
• Temporalis : close the jaw , retract it slightly
• Medial pterygoids : close the jaw & protrude it
• Lateral pterygoids : open the jaw & protrude it
• - Unilateral pterygoid weakness – jaw deviates towards side of weak muscle
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Also supplies• Mylohyoid• Ant.belly of
digastric• Tensor veli
palatini• Tensor tympani
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Trigeminal Neuralgia
• Compression, degeneration or inflammation of the 5th cranial nerve may result in a condition called trigeminal neuralgia or tic douloureux.
• This condition is characterized by recurring episodes of intense stabbing , excoriating pain radiating from the angle of the jaw along a branches of the trigeminal nerve.
• Usually involves maxillary & mandibular nerves, rarely in the ophthalmic division.
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