Week 4.0 - Cranial Nerves Flashcards
How do CNI and II differ from the rest?
-They are atypical in that they are brain tracts (outpouchings of axons)
What is a pneumonic to remember the cranial nerves?
- Oh, Oh, Ot, to touch and feel very good vagina ah heaven
- olfactory, optic, oculomotor, trochlear, Trigeminal, abducens, facial, vestibulocochlear, glossopharyngeal, vagus, accessory spinal, Hypoglossal
What is a pneumonic to remember each of the cranial nerve types?
- Some Say Marry Money but my brother says big boobs matter more
- Sensory, sensory, motor (a), motor, both, motor, both (a), sensory, both(a), both(a), motor, motor
Which cranial nerves originate in the midbrain?
-3/4
Which cranial nerves originate in the pons?
-5,6,7
Which cranial nerves originate in the medulla oblongata?
-8,9,10,11,12
Name Cranial nerve I
What type of nerve is it?
Where is it from/to?
What is its function?
- Olfactory
- Sensory
- Olfactory mucosa through cribriform plate to form olfactory bulb to olfactory tract
- Sense of smell
Where is cribriform plate?
-Ethmoid bone
What is anosmia?
-Lack of smell
Give 3 major causes of anosmia
- Upper respiratory tract infection
- Trauma (eg fracture cribriform plate damages nerves)
- Meningitis
How do you test CNI?
-Ask patient to smeel coffe/orange/smelling salts
Name CN II
What type of nerve is it?
Where if is from/to?
What is its function?
- optic nerve
- Sensory
- Complex pathway from the retina to optic tract through optic canal then primary visual cortex
- Sight
How do you test CNII?
-Visual acuity (snellen chart) (-Colour Vision) -Visual fields -Pupillary reflexes -Fundoscopy
Name CNIII
What type of nerve is it?
Where is it from/to?
What is its function
- Oculomotor
- Motor (parasympathetic)
- From Oculomotor nucleus (edinger-westphal nucleus) in midbrain to most extraocular muscles
- Move eyeball/eye lid (pupillary constriction)
Name the muscles which oculomotor nerve innervates
-Inferior oblique
-Superior, inferior, medial rectus
-Levator palpabrae Superioris
(-Pupillae constrictor)
Through which foramina does optic nerve pass?
-Optic canal
Through which foramina foes oculomotor nerve pass?
-Superior orbital fissure
How do you test oculomotor nerve?
-H test
How would a strict oculomotor nerve palsy present?
- Down and out pupil
- Ptosis
How will a complete oculomotor nerve palsy present?
- Down and out pupil
- Ptosis
- Myadriasis (blown pupil)
Name CN IV
What type of nerve is it?
Where is it from/to?
What is its function?
- Trochlear
- Motor
- From trochlear nucleus in dorsal Midbrain to superior oblique of the eye
- Look down and in (Moves the eye down when the eye is adducted - also contributes to abduction and depression although weakly)
What is special about trochlear nerve?
-It has the longest intracranial length
What structures travel through the cavernous sinus?
- CN III, IV, V(V1/V2) VI,
- Internal carotid artery
Through which foramina does trochlear travel?
-Superior orbital fissure