LAST 4 CRANIAL NERVES

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LAST 4 CRANIAL NERVES
Dr. Ahmed Fathalla Ibrahim
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LAST 4 CRANIAL NERVES
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GLOSSOPHARYNGEAL NERVE
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GLOSSOPHARYNGEAL NERVE

• Types of fibers mixed
• Sensory ganglia superior inferior
• Exit from cranial cavity through jugular foramen
• Course in neck
• Descends between internal jugular vein internal
  carotid artery
• Curves around stylopharyngeus muscle runs
  between internal external carotid arteries
• Crosses stylopharyngeus runs between hyoglossu
  genioglossus muscles to reach the tongue

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GLOSSOPHARYNGEAL NERVE

• Branches
• Lingual carries general taste sensations from
  posterior 1/3 of tongue
• Pharyngeal carries sensory fibers from pharynx
• Tonsillar carries sensory fibers from palatine
  tonsils
• Muscular to stylopharyngeus muscle
• Tympanic carries sensory fibers from tympanic
  cavity inner surface of tympanic membrane,
  forms a plexus from which arises the lesser
  petrosal nerve carrying preganglionic
  parasympathetic fibers to parotid gland
• To carotid sinus body

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GLOSSOPHARYNGEAL NERVE

• Applied anatomy pain of tonsilitis may be
  referred to middle ear through glossopharyngeal
  nerve because the nerve supplies both structures

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VAGUS NERVE
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VAGUS NERVE

• Types of fibers mixed
• Sensory ganglia superior inferior
• Exit from cranial cavity through jugular foramen
• Course in neck
• Descends between internal jugular vein internal
  carotid artery
• Continues in carotid sheath between internal
  jugular vein common carotid artery
• At root of neck, crosses subclavian artery to
  reach the thorax

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VAGUS NERVE

• Branches
• Pharyngeal contains motor fibers from cranial
  part of accessory nerve to all pharyngeal
  (except stylopharyngeus) all palatine (except
  tensor palati) muscles
• Superior laryngeal divides into internal
  laryngeal carries sensory fibers from larynx
  (above vocal folds) general taste sensations
  from vallecula external laryngeal carries
  motor fibers to cricothyroid muscle
• Recurrent laryngeal carries sensory fibers from
  larynx (below vocal folds) motor fibers to all
  laryngeal muscles (except cricothyroid)

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VAGUS NERVE

• Branches
• 4. Auricular carries sensory fibers from
  external auditory meatus outer surface of
  tympanic membrane
• 5. Meningeal to dura of posterior cranial fossa
• 6. Cardiac

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ACCESSORY NERVE
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ACCESSORY NERVE

• Types of fibers motor
• Elements formed of
• Cranial part emerging from medulla
• Spinal part formed by fusions of roots emerging
  from upper 5 or 6 cervical segments of spinal
  cord then enters cranial cavity through foramen
  magnum joins cranial part
• Exit from cranial cavity through jugular foramen

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ACCESSORY NERVE

• Course in the neck both parts separates after
  emergence from cranial cavity
• Cranial part is distributed along pharyngeal
  recurrent laryngeal branches of vagus
• Spinal part
• Descends between internal jugular vein internal
  carotid artery
• Curves backward, superficial to internal jugular
  vein then deep to sternomastoid (to reach
  posterior triangle of neck
• Passes superficial to levator scapulae the deep
  to tapezius
• Supplies motor fibers to sternomastoid trapezius

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PHARYNGEAL PLEXUS OF NERVES

• Site on lateral surface of middle constrictor
• Formation by pharyngeal branches of
• Vagus (carries cranial part of accessory nerve)
• Glossopharyngeal
• Superior cervical sympathetic ganglion

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HYPOGLOSSAL NERVE

• Types of fibers motor
• Exit from cranial cavity through hypoglossal
  canal
• Course in neck
• Descends between internal jugular vein internal
  carotid artery
• Curves forward superficial to internal
  external carotid arteries, lingual artery,
  hyoglossus genioglossus
• Branches motor to all muscles of tongue except
  palatoglossus