Control L7 cranial nerves Flashcards
Which 10 cranial nerves emerge from the brainstem?
CN III - XII
What cranial nerves are part of the CNS?
CN I & II
What part of the nervous system are cranial nerves that derive from the brainstem part of? (Central/peripheral)
Peripheral
Where did the optic nerve (CN II) develop from?
Diencephalon
Where do the olfactory bulb and olfactory tract of CN I originate from?
Telencephalon
For each fibre type within a CN, there is a corresponding nucleus in the brainstem. True or false?
True
How many nuclei are associated with the occulomotor nerve?
2 - one for somatic motor fibres (occulomotor nuclei) and the other (Edinger-Westphal nuclei) for the autonomic visceral motor fibres
Where on the brainstem are sensory nuclei located?
Laterally
Where on the brainstem are motor nuclei located
Medially
What part of the brainstem are cranial nerve nuclei located?
Tegmentum
How many cranial nerve nuclei are in the brainstem?
17
Where are cranial nerve nuclei found in relation to the ventricular system?
anteriorly
What are three examples of motor nuclei found in the open medulla?
Somatic motor
Parasympathetic motor
Head and neck motor
What are three examples of sensory nuclei found in the open medulla?
Special sensory
Somatic sensory
Visceral sensory
What innervation is the somatic motor nuclei involved in?
Somatic skeletal muscles
What innervation is the parasympathetic motor nuclei involved in?
Secretion of glands
What innervation is the head and neck motor nuclei involved in?
Some muscles of the head and neck
What innervation is the special sensory nuclei involved in?
Senses (smell, vision, taste, hearing, balance)
What innervation is the somatic sensory nuclei involved in?
General sensation (touch) from the peripheries
What innervation is the visceral sensory nuclei involved in?
Sensation of internal organs and glands
What innervation is the branchial motor nuclei involved in?
Muscles derived from pharyngeal arches
How many CN are purely motor (efferent) fibres?
5
How many CN are purely sensory (afferent) fibres?
3
How many CN are a mix of efferent and afferent fibres?
4
Which part of the brainstem are CN nuclei found?
All parts - medulla, pons and midbrain
What is CN I?
Olfactory nerve
Where does CN I originate from?
the nasal mucosa
How does CN I communicate with the brain?
nerve travels from the nasal mucosa, merges with the olfactory bulbs and olfactory tract which are extensions of the telencephalon
What foramina does CN I pass through?
cribriform plate
What type of nuclei does CN I have?
Special sensory
What is the function of CN I?
olfaction aka smell
How can you test the function of CN I?
with a smell test e.g. an orange
What is the term for not being able to smell?
Anosmia
What is CN II?
Optic nerve
Where does CN II originate?
The retina
How does CN II communicate with the brain?
Emerges from the retina and travels to the optic chiasma into the optic tracts carrying visual information to the thalamus
What part of the brain are CN II extensions of?
diencephalon
What foramina do CN II travel through?
Optic canal
What type of nuclei does CN II have?
Special sensory
What is the function of CN II?
vision
How do we test the function of CN II?
Various visual tests
What is the only sensory modality that does not travel through the thalamus?
Smell/olfaction
What is CN III?
Occulomotor
Where does CN III emerge?
Pontomesencephalic junction (where pons and midbrain meet)
What foramen does CN III travel through?
superior orbital fissure
What nuclei are found in CN III?
somatic motor and visceral parasympathetic motor
What muscles are supplied by CN III?
the four extraocular muscles and Levator palpebrae superioris (somatic motor fibre)
Ciliary muscle and sphincter pupillae (parasympathetic autonomic motor fibres)
What is CN IV?
Trochlear
Where does cranial nerve IV emerge from?
Dorsal midbrain
What foramen does CN IV travel through?
Superior orbital fissure
What nuclei are found in CN IV?
somatic motor
What muscle is supplied by CN IV?
superior oblique muscle
What is CN VI?
Abducens
Where does CN VI emerge?
pontomedullary junction (where pons and medulla meet)
What foramen does CN VI travel through?
superior orbital fissure
What nuclei is found in CN VI?
somatic motor
What muscle is supplied by CN VI?
Lateral rectus
How is function of CN III, IV and VI tested?
Follow finger (H) test
How do signals reach the ciliary muscles and sphincter pupillae from CN III?
The preganglionic fibres of CN III travel to the ciliary ganglion and the postganglionic fibres then travel to the muscles to innervate
What muscle closes the eyelid?
Orbicularis oculi
What CN is involved in closing the eyelids/ innervating orbicularis oculi?
CN VII
What muscle opens the eyelid?
Levator palpebrae superioris
(+ superior tarsal muscle sympathetically - e.g. in surprise, fear or excitement - by elevating upper eyelid)
Which muscle keeps the eyelid open?
Superior tarsal muscle
What CN is involved in innervating levator palpebrae superioris in opening/dilating the superior eyelid?
CN III (motor fibres)
What muscles dilate the pupil?
The dilators of the iris
Are the dilators of the iris innervated parasympathetically or sympathetically?
Sympathetically
What muscles are involved in constricting the pupil and changing the lens shape?
Sphincter pupillae and the ciliary muscle
Are sphincter pupillae and the ciliary muscle innervated sympathetically or parasympathetically?
Parasympathetically
What is CN V called?
Trigeminal nerve
How many subdivisions does the trigeminal nerve have?
3
What are the three subdivisions of the trigeminal nerve?
Opthalmic (V1)
Maxillary (V2)
Mandibular (V3)
Where does CN V emerge from?
The lateral sides of the pons
What foramen does CN V1 travel through?
Superior orbital fissure
What foramen does CN V2 travel through?
Foramen rotundum
What foramen does CN V3 travel through?
Foramen ovale
What nuclei are found in CN V?
Somatic sensation in V1, V2 and V3
Branchial motor in V3
What is the function of CN V1?
Sensation of upper face (above eye)
What is the function of CN V2?
sensation from middle face (between eye and mouth)
What is the function of CN V3?
Sensation from lower face, mandible and anterior 2/3 of the tongue
Innervation of muscles including muscles of mastication, anterior belly of the digastric muscle and tensor tympani.
How do you test for function of CN V?
V1 = cotton wool on forehead and corneal reflex test
V2 = cotton wool on cheek
V3 = cotton wall on jaw, clench teeth and feel masseter muscle, move jaw side to side against resistance to test pterygoid muscles, protrude jaw and jaw jerk reflex.
What are four autonomic ganglia associated with CN V?
Ciliary
Pterygopalatine
Submandibular
Otic
What is CN VII called?
Facial nerve
Where does CN VII emerge from?
The cerbellopontine angle (medially to CN VIII)
What foramen does CN VII enter the skull?
Internal acoustic meatus
What foramen does CN VII exit the skull?
Stylomastoid foramen
What nuclei are found in CN VII?
Branchial motor, visceral parasympathetic motor, special sensory and somatic sensory
What is the branchial motor function of CN VII?
Innervate muscles of facial expression, strapedius muscle, posterior belly of the digastric muscle
What is the visceral parasympathetic motor function of CN VII?
Innervate all glands (except parotid) to secrete
What is the special sensory function of CN VII?
Taste on anterior 2/3 of tongue via chorda tympani
What is the somatic sensory function of CN VII?
Sensation to skin of ear
How do you test function of CN VII?
Test facial movements and expressions, taste and salivation
What is CN VIII called?
Vestibulocochlear
Where does CN VIII emerge from?
The cerebellopontine angle (laterally to CN VII)
What foramen does CN VIII travel through?
Internal acoustic meatus
What nuclei are found in CN VIII?
Special sensory
What is the function of CN VIII?
Hearing and balance
How do you test the function of CN VIII?
bedside hearing tests like Rinne’s and Weber’s
What is the name of CN IX?
glossopharyngeal
Where does CN IX emerge from?
Posterolateral sulcus of medulla, lateral to the olives
What foramen does CN IX travel through?
jugular foramen
What nerve fibres are found in CN IX?
Branchial motor, visceral parasympathetic motor, special sensory, somatic sensory and visceral sensation
What is innervated by the branchial motor fibres of CN IX?
Pharynx in order to swallow
What is innervated by the visceral parasympathetic motor fibres of CN IX?
Parotid gland
What is innervated by the special sensory fibres of CN IX?
The middle ear, pharynx and posterior 1/3 of the tongue
What is innervated by the visceral sensation fibres of CN IX?
the carotid body and carotid sinus monitoring O2 sats and BP.
How can the function of CN IX be tested?
Assessing gag reflex
What is CN X called?
Vagus nerve
Where does CN X emerge from?
The posterolateral sulcus of the medulla laterally to the olives (inferior to CN IX)
What foramen does CN X travel through?
Jugular foramen
What nerve fibres does CN X contain?
Branchial motor, visceral parasympathetic motor, visceral sensory, special sensory and somatic sensory
What does the branchial motor fibres of CN X innervate?
the muscles of the pharynx, larynx and soft palate and uvula
What do the visceral parasympathetic motor fibres of CN X innervate?
Thoracic and GI tract muscles
What do the visceral sensory nerve fibres of CN X innervate?
Thoracic and GI sensation
What do the special sensory fibres of CN X innervate?
Taste from epiglottis and palate
What do the somatic sensory fibres of CN X innervate?
Sensation from epiglottis, larynx and skin of external ear
How do you test the function of CN X?
Assessing speaking and movement of the uvula
What is CN XI called?
Accessory nerve
Where does CN XI emerge from?
The caudal medulla and rostral spinal cord
What foramen does CN XI travel through?
Jugular foramen
What nerve fibres are found in CN XI?
Somatic motor
What does CN XI innervate?
Motor function of sternocleidomastoid and trapezius muscles
How do you test for the function of CN XI?
By assessing ability to shrug shoulders and rotate head against resistance.
What is CN XII called?
Hypoglossal
Where does CN XII emerge from?
anterolateral sulcus between the pyramids and the olives
What foramen does CN XII travel through?
Hypoglossal canal
What nerve fibres are found in CN XII?
somatic motor
What is the function of CN XII?
Motor Innervation of muscles of the tongue
How do you test for the function of CN XII?
Assess protrusion of the tongue.
Which spinal roots contribute to CN XI?
Spinal roots of C1-C5
How do the spinal roots join with CN XI?
Travel up through the foramen magnum into the skull and combines with the cranial root to form CN XI before leaving via the jugular foramen
If damage to the CN XII, which side does the tongue protrude towards?
The paralysed side
Which cranial nerves contain preganglionic autonomic fibres?
III
VII
IX
X
What ganglia is associated with CN III?
Ciliary
What ganglion is associated with CN VII?
Pterygopalatine
What ganglion is associated with CN IX?
Submandibular
What ganglion is associated with CN X?
Otic
What nerve do the postganglionic autonomic fibres of the ciliary, pterygopalatine and submandibular ganglia travel with?
Trigeminal
What muscle and function is the ciliary ganglion associated with?
Pupil constriction by the sphincter pupillae
What gland and function is the pterygopalatine ganglion associated with?
Lacrimation via the lacrimal gland
What gland and function is the submandibular ganglion associated with?
salivation by the submandibular, sublingual, parotid gland
