CN VII: Facial Nerve
Overview
Roles
- Special sensory (taste) - anterior ⅔ of tongue
- Somatic sensory - external ear, posterior auricle (Ramsay-Hunt zone)
- Somatic motor - facial expression, eye closing
- Visceral motor (parasympathetic) - submandibular & sublingual salivary glands, lacrimal glands, nasal & palatine glands
Facial Nerve Palsy
Abnormalities
- Facial droop / weakness
- Inability to close eye
- Loss of taste
- Dry eyes / mouth
Causes of Facial Nerve Palsy
- Supranuclear
- Ischaemic stroke (lacunar or superior cerebellar artery)
- Tumour - primary / secondary
- Nuclear / Infranuclear
- Bell’s palsy (idiopathic)
- Ramsay-Hunt syndrome (Herpes zoster)
- Tumour - primary / secondary
- Parotid gland pathology
- Otitis media / externa
- Skull fracture
- Guillain-Barre
- Ischaemia
- Lyme disease
- Leprosy
Motor Pathway
- Cortical Centre
Primary motor cortex (precentral gyrus)Facial Motor Nucleus
PonsForamen
Internal auditory meatusGeniculate GanglionDivision
Temporal, zygomatic, buccal, marginal mandibular and cervical branchesMuscles
Facial expression, orbicularis oculi
Special Sensory Pathway
- Gustatory Cortex
InsulaThalamusFacial Sensory Nucleus
PonsForamen
Internal auditory meatusGeniculate GanglionChorda Tympani Nerve
Sensory and parasympathetic fibresReceptors
Anterior ⅔ of tongue
Parasympathetic Pathway
- Visceral Nuclei
Superior salivatory & lacrimal nuclei (pons)Pathway
Tegmentum, red nucleus, medial substantia nigraForamen
Internal auditory meatusGeniculate GanglionMuscle
Lacrimal glands, salivary glands, nasal & palatine glands
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