Cranial Nerves Flashcards
After leaving the brain stem where do the cranial nerves arising from the medulla enter?
Carotid sheath
Which CNs arise from the midbrain pontine junction and the pontine-Medullary junction?
Which CN originates anterior to the olive of the medulla?
MB-PJ
- III
PMJ
- VI
- VII
- VIII
Hypoglossal (XII)
Why can a tumour at the base of the frontal lobes lead to anosmia?
Impingement of CN I
What does the brainstem communicate with the optic tract via?
Superior colliculus
You shine light of left eye and only see a consensual light reflex.
Where is the lesion?
Left occulomotor nerve
Anuerysm of what artery can compress on CNIII?
Where else is it vulnerable to compression?
In a vascular problem secondary to hypertension or diabetes, what is unique about presentation?
Posterior communicating artery
Tentorium cerebelli and temporal lobe - raised ICP causing uncal herniation.
Cavernous sinus thrombosis
Pupil sparing
What can be noticed about patients head in trochlear nerve palsy? Why?
Tilted away from the side of the lesion. Minimise diplopia
Give 2 conditions that can affect the trigeminal nerve.
Trigeminal neuralgia
Shingles
What are the 3 branches of the Vc?
Inferior alveolar
Lingual
Auriculotemporal
Why is CN VI more vulnerable to raised ICP?
Runs on the under surface of the pons before making a sharp turn as it heads towards the cavernous sinus
Which nucleus do the autonomic fibres to salivary, lacrimal, nasal mucosal and palate glands originate (parasympathetics)?
Superior salivatory nucleus
What ganglion does the greater petrosal nerve synapse in?
Pterygopalatine
What are the afferent and efferent limbs of the corneal reflex?
Va
CNVII
Name 3 important symptoms that could be associated with CNVII palsy
Hyperacusis
Dry eyes
Dusguesia
What is an acoustic neuroma?
Why is facial weakness seen?
Symptoms?
Benign tumour of the Schwann cells surrounding the vestibular component of CN VIII
Facial nerve runs through IAM also in close proximity
Unilateral sensorineural hearing loss
Vertigo
Tinnitus
Numbness or pain down half of face
Give general sensory special sensory, autonomic and motor functions of glossopharyngeal.
General sensory
- Palatine tonsils and oropharynx
- Middle ear and inner membrane
- Carotid body and sinus
- Posterior 1/3 tongue
Special sensory
- Posterior 1/3 tongue
Autonomic
- Parasympathetics to parotid gland
Motor
- Stylopharyngeus
Give general sensory functions of the vagus nerve.
Laryngo pharynx and larynx Tympanic membrane (external surgical) Posterior external ear
How can you test for accessory nerve damage?
Which anatomical region does it run through?
Shrug shoulders against resistance or turn head against resistance
Posterior triangle posterolaterally
Describe the route of the hypoglossal nerve.
What is its function?
Originates from the medulla anterior to the Olive and exits the cranium via the hypoglossal canal
It then runs medial to the angle of mandible and crosses the internal and external carotid arteries in the neck.
Tongue muscle innervation except palatoglossus
In which nerve palsy will you diplopia which worsens of downward gaze?
Trochlear
