20. Cranial Nerves 1-6 Flashcards
What is the name of the first cranial nerve?
Olfactory
Where do signals from the olfactory tract go?
Medial and lateral olfactory stria
Where do signals from the olfactory stria go?
Temporal lobe
Where do olfactory signals from the temporal lobe go?
Olfactory cortex
What are the parts of the olfactory cortex?
Piriform cortex
Amygdala
Enterhinal cortex
Where do signals from the olfactory cortex go?
Orbitofrontal cortex
How can you test the first cranial nerve?
Test smell in each nostril
What is the name of the second cranial nerve?
Optic nerve
How can you test the second cranial nerve?
Snellen chart
Visual field test
Pupillary light reflex
What is the visual field?
Total area of each eye where we can see images
What is it called when the visual field is tested using instruments?
Perimetry
What is papilloedema?
Swelling of the optic disc
What is papilloedema caused by?
Increased ICP
What nucleus in the midbrain do some fibres from the eye synapse in?
Pretectorial nucleus
What parasympathetic nucleus is stimulated in the pupillary light reflex?
Edinger-Westphal
What muscle do post ganglionic parasympathetic neurons act on in the pupillary light reflex?
Constrictor pupillae
What does PEARL test?
Pupils Equal and Reactive to Light
Midbrain,
Optic nerve
Occulomotor nerve
What is the test for cranial nerves 3, 4 and 6?
Ask patient to keep their head still and ask them to follow your finger as you make a H shape in the air
Watch for nystagmus, diplopsia
What is the name of the third cranial nerve?
Occulomotor
Which muscles does the occulomotor nerve act on?
Levator palpebrae superioris
superior, inferior and medial rectus
inferior oblique
What reflexes travel in III?
Pupillary light reflex
Accommodation
Which cranial nerves run in the brainstem midline?
3, 4, 6, 12
Which cranial nerves run in the lateral brainstem?
5, 7, 9, 11
What is the name of the fourth cranial nerve?
Trochlear
Which muscle does the trochlear nerve act on?
Superior oblique
Which cranial nerves leave through the pons?
5, 6, 7, 8
Which cranial nerves leave through the medulla?
9, 10, 11, 12
Which cranial nerves leave above the brainstem?
1, 2
Which cranial nerves leave in the brainstem?
3, 4
What is the name of the sixth cranial nerve?
Abducens
Which muscle does abducens control?
Lateral rectus
What are the signs of an extradural hematoma?
Pupil will initially constrict and later dilate on the same side as the hematoma
What is the name of the fifth cranial nerve?
Trigeminal
How is the 5th cranial nerve tested?
Corneal reflex
Test for fine touch in the area of each of its branches
Which muscle is involved in the corneal reflex?
Orbicularis oculi
Which nerves are involved in the corneal reflex?
Afferent: Opthalamic
Efferent: facial
What is lens accommodation?
Adaptation of the eye to look at near objects
What actions happen in accommodation?
Increase in lens curvature
Constrict pupil
Convergence of the eye
What muscle causes convergence of the eye in accommodation?
Medial rectus
