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Cranial Nerve 7Aka: Cranial Nerve VII, Facial Nerve, CN 7, Geniculate Ganglion

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  1. Causes of Paralysis
    1. Multiple Sclerosis
    2. Neoplasm
    3. Guillain-Barre Syndrome (Infectious polyneuritis)
    4. Syphilis
    5. Bell's Palsy
    6. Melkersson's Syndrome (Recurrent Bell's Palsy)
    7. Poliomyelitis
    8. Amyotrophic Lateral Sclerosis (ALS)
    9. Syringomyelia
  2. Physiology: Course to Geniculate ganglion
    1. General
      1. Facial nerve originates in four nucleii in pons and medulla
      2. All combine to travel via internal auditory meatus into geniculate ganglion
    2. Somatic Motor Component (Innervates muscles of facial expression and stapedius)
      1. Originates in pons at facial nucleus
      2. Circles centrally around 6th Cranial Nerve nucleus and by fourth ventricle
    3. Visceral Motor component (Lacrimal gland, submaxillary and Submandibular Glands)
      1. Originates in medulla at superior Salivatory nucleus
    4. Somatic Sensory component (external ear sensation along with CN 9 and 10)
      1. Originates in medulla at spinal nucleus of Cranial Nerve 5
    5. Visceral Sensory Component (taste for anterior two-thirds of Tongue)
      1. Originates in medulla at solitary tract nucleus
  3. Physiology: Geniculate Ganglion to motor branches
    1. Ganglion within facial canal between labyrinthine and tympanic segments
    2. Facial nerve turns 90 degrees to travel inferiorly through stylomastoid foramen
    3. Facial nerve branches (motor innervation)
      1. Temporal branch (forehead and eye)
      2. Zygomatic branch (vicinity of zygomatic arch)
      3. Buccal branch (cheek)
      4. Marginal mandibular branch (jaw line)
      5. Cervical branch (neck)
      6. Posterior auricular nerve branch (posterior to ear back to occiput)
  4. Physiology: Innervation
    1. Contains motor, autonomic, and sensory fibers
    2. Motor fibers
      1. Scalp, Face, and Auricula
      2. Buccinator Muscle
      3. Platysma Muscle
      4. Stapedius Muscle
      5. Stylohyoid Muscle
      6. Posterior Belly of Digastric Muscle
    3. Autonomic motor fibers
      1. Vasodilatation and secretion of Salivary Glands
        1. Submaxillary gland
        2. Sublingual Gland
    4. Sensory fibers
      1. Taste for anterior two thirds of Tongue
      2. Sensation to ear canal and behind ear
  5. Exam
    1. Facial Motor Exam
      1. Forehead and Upper lid Innervation
        1. Eyebrow elevation
        2. Forehead wrinkling
        3. Frowning
        4. Tight Closing of the eyes
      2. Lower Face innervation
        1. Showing teeth
        2. Whistling
        3. Puffing cheeks
        4. Natural smile
        5. Test or inquire about Taste Sensation
    2. Distinguish level of Facial Nerve lesion
      1. Upper Motor Neuron (UMN)
        1. Unless bilateral lesion, does not affect forehead
        2. Mouth paralysis is overcome by emotional expression
      2. Lower Motor Neuron (LMN)
        1. Ipsilateral forehead and lower face paralysis

Facial nerve structure (C0015462)

Definition (MSH)The 7th cranial nerve. The facial nerve has two parts, the larger motor root which may be called the facial nerve proper, and the smaller intermediate or sensory root. Together they provide efferent innervation to the muscles of facial expression and to the lacrimal and salivary glands, and convey afferent information for taste from the anterior two-thirds of the tongue and for touch from the external ear.
Definition (CSP)seventh cranial nerve; has two parts, the larger motor root which may be called the facial nerve proper, and the smaller intermediate or sensory root, which together provide efferent innervation to the muscles of facial expression and to the lacrimal and salivary glands, and convey afferent information for taste from the anterior two-thirds of the tongue and for touch from the external ear.
Definition (NCI)The 7th cranial nerve. The facial nerve has two parts, the larger motor root which may be called the facial nerve proper, and the smaller intermediate or sensory root. Together they provide efferent innervation to the muscles of facial expression and to the lacrimal and salivary glands, and convey afferent information for taste from the anterior two-thirds of the tongue and for touch from the external ear. (MeSH)
ConceptsBody Part, Organ, or Organ Component (T023)
EnglishBranchiomeric cranial nerve, Cranial Nerve VII, Cranial Nerve VIIs, Facial Nerve, Facial nerve structure, Facial nerve tree, Seventh Cranial Nerve
Spanishestructura del nervio facial, nervio facial, séptimo nervio craneal, séptimo par craneal, séptimo par craneano, septimo nervio craneal, septimo par craneal, septimo par craneano, VII par craneal
CreditsDerived from the NIH UMLS (Unified Medical Language System)



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