Flashcards in Cranial Nerves Deck (110)
Which cranial nerve innervates muscles derived from the first pharyngeal arch?
Trigeminal (V3- Mandibular)
Which cranial nerve innervates muscles derived from the second pharyngeal arch?
Facial (CN VII)
Which cranial nerve innervates muscles derived from the third pharyngeal arch?
Glossopharyngeal (CN IX)
Which cranial nerve innervates muscles derived from the fourth pharyngeal arch?
Sup laryngeal branch of vagus (CN X)
Which cranial nerve innervates muscles derived from the sixth pharyngeal arch?
Recurrent laryngeal branch of vagus (CN X)
Which pharyngeal arch never develops?
Where does CN I enter the skull?
Foreamina of the Cribiform plate in ethmoid bone
What is the embryological origin of CN I?
Embryonic nasal placode
What nuclei are associated with CN I?
Olfactory bulbs (ant cranial fossa)
What is olfactory mucosa?
Made of olfactory epithelium and underlying lamina propria (connective tissue with BV's). The mucus protects epithelium and allows odours to dissolve for detection
What is the origin of CN II?
Ganglion cells in retina
Where does CN II exit the skull?
Through optic canal (into middle cranial fossa)
Describe the course of CN II
Ganglion cells > optic canal > optic chiasm > optic tract > LGN > visual cortex
Where is the termination of CN II?
Lateral geniculate nucleus (in thalamus)
What tests can be done to test CN II?
Visual acuity (Snellen)
Assess visual fields (Move wagging finger)
Asses pupillary light reflex- both should constrict when one eye stimulated
What are the efferent muscles supplied by CN III?
Med/ Sup/ Inf Rectus
Levator palpebrae superioris
What autonomic supply is provided by CN III?
(Both PNS- Ciliary ganglion)
Where does CN III originate?
Ant surface brainstem (between mid brain and pons)
What nuclei are associated with CN III?
Where does CN III exit the skull?
Superior orbital fissue
What are the two divisions of CN III, where do they split?
Superior: Sup rectus and LPS
Inferior: Med/ inf rectus + inf oblique + ciliary muscles + sphincter pupillae
What is the course of CN III?
From midbrain, along lateral wall of cavernosus sinus, into orbit through SOF (then splits into sup and inf divisions)
How do you test CN III?
Draw H with finger, check P can follow
Check accommodation (pupils constrict)
Test pupil constriction
What is controlled by CN IV?
Superior oblique muscle
Where does CN IV originate?
From post brainstem (just below inf colliculus)
ONLY CN TO EMERGE POST
Where does CN IV leave the skull?
Sup orbital fissure
What nucleus is associated with CN IV?
How do you test CN IV?
Ask P to look out and down
(Ask if experiencing diplopia)
What is the course of CN IV?
Passes round to ant brainstem, goes along inf surface of tentorium cerebeli (seperates cerebellum and occipital lobe), then along lateral wall of cavernous sinus