Session 8 - Cranial Nerves and Assessment of Function Flashcards Preview

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Flashcards in Session 8 - Cranial Nerves and Assessment of Function Deck (53)
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Which PA is CN V a derivative of?

1st PA


What is the sensory innervation of CN V

skin, mucous membranes, and sinuses of face


What is the motor innervation of CN V?

mandibular branch innervates muscles of mastication as well as anterior belly of digastric, tensor veli palatine, and tensor tympani


What is the relationship of parasympathetic ganglia and CN V?

post ganglionic neurones of PS ganglia travel WITH but NOT part of trigeminal nerve



Where is the trigeminal ganglion found?

middle cranial fossa

Lateral to cavernous sinus in a depression in temporal bone known as trigeminal cave


What is a nucleus and a ganglion with relation to nerves?

Nucleus – collection of nerve cell bodies WITHIN CNS
Ganglion – collection of nerve cell bodies OUTSIDE CNS


What is the name of V1,  V2, and V3?

V1 – ophthalmic.

V2 – Maxillary.

V3 – Mandibular



Through which foramen do the ophthalmic and maxillary nerves travel?

Ophthalmic - superior orbital fissure

Maxillary - foramen rotundum 


Through which foramen does the mandibular nerve travel through?

foramen ovale


What nerves does the ophthalmic nerve give rise to?

frontal, lacrimal, nasociliary


What sensory structures does the ophthalmic innervate?

Innervate skin and mucous membrane derivatives of the frontonasal prominence:

  • Forehead and scalp
  • Frontal and ethmoidal sinus
  • Upper eyelid and its conjunctiva
  • Cornea
  • Dorsum of nose


Describe the PS supply of the lacrimal gland

Post ganglionic fibres from pterygopalatine ganglion travel with the zygomantic branch of V2 and then join the lacrimal branch of V1. These fibres supply PS innervation to lacrimal gland


What is the corneal reflex? What nerves are involved and what is an absent reflex indicative of?

  • Involuntary blinking of eyelids stimulated by stimulation of cornea
  • Ophthalmic nerve acts as afferent limb, facial nerve is the efferent limb.
  • If reflex absent à sign of damage to the trigeminal/ophthalmic nerve or facial nerve.


Which PA is maxillary derived from?

1st PA


What structures does the maxillary innervate?

derivatives of maxillary prominence of 1st PA: 

  • Lower eyelid and its conjunctiva
  • Cheeks and maxillary sinus
  • Nasal cavity and lateral nose
  • Upper lip
  • Upper molar, incisor , and canine teeth and associated gingiva
  • Superior palate


What nerves does the mandibular nerve give rise to?

Gives rise to buccal, inferior alveolar, auricotemporal, and lingual nerve 


What sensory structures does the mandibular innervate?

Derivatives of mandibular prominence of 1st PA:

  • Mucous membranes and floor of oral cavity
  • External ear
  • Lower lip
  • Chin
  • Anterior 2/3rds of tongue (only general sensation)
  • Lower molar, incisor, and canine teeth and associated gingiva


What motor structures does the mandibular nerve innervate?

  • Muscles of mastication
  • Anterior belly of digastric muscle
  • Tensor veli palatine
  • Tensor tympani



What is the PS supply of the mandibular nerve?

  • Submandibular and sublingual glands
  • Parotid gland


Where does the inferior alveolar nerve travel through?

Mandibular foramen and mandibular canal.


What clinically relevant structures does the inferior alveolar nerve innervate?

 inferior alveolar nerve forms the inferior dental plexus which innervates the lower teeth


Why is the inferior alveolar nerve blocked for some dental procedures? Where is it blocked? Where is anaesthetic administered?

  • Inferior alveolar nerve blocked for some dental procedure, before it gives rise to plexus
  • Anaesthetic administered at mandibular fossa.


How would you test the sensory supply of the trigeminal nerve?

Patient closes eyes and you introduce a cotton wisp to areas of face supplied by trigeminal nerve


How would you test the motor supply of the trigeminal?

  • Ask patient to clench jaw as you palpate temporalis and then repeat palpating inferiorly for masseter
  • Ask patient to open their mouth and deviate their mandible right and left, checking for competence of medial and lateral pterygoid muscles.


How would you test the corneal reflex? What nerves is it checking for?

  • Requires competent ophthalmic branch and temporal and zygomatic branches of facial nerve
  • Cotton wisp on eye.


What motor structures does CN III innervate?

extraocular muscles


What structures do the PS and sympathetic nerves that run with CN III innervate?

PS – supplies sphincter pupillae and ciliary muscles of eye

Sympathetic – runs with oculomotor nerve to innervate superior tarsal muscle