Anatomy: Cranial Nerves Flashcards
Which cranial nerve innervates a contralateral muscle (decussates)?
Trochlear nerve (CN IV)
Which cranial nerve does eye movement, accommodation, and pupil constriction (miosis?
Oculomotor (CN III)
Which cranial nerve innervates only the superior oblique muscle?
Trochlear (CN IV)
Which cranial nerve innervates only the lateral rectus muscle?
Abducens (CN VI)
What is the function of the abducens nerve?
Innervates lateral rectus which abducts the eye (points it out)
Which nerves allow for the gag reflex?
Glossopharyngeal (CN IX) - sensory
Vagus (CN X) - motor
If there is a lesion to a cranial nerve affecting the tongue which way will the tongue deviate?
Towards the lesion
Tongue Toward
If there is a lesion to the vagus nerve (CN X), which way will the uvula deviate?
Away from the lesion
Uvula Away
Which part of the colon is innervated by the vagus nerve?
Ascending and first 2/3 of transverse
What functions are stimulated by the accessory nerve (CN XI)?
Head turning, shoulder shrugging (SCM and trapezius)
Where do the fibers from the optic nerve travel to?
The lateral geniculate nucleus in the thalamus -> occipital cortex
*some go to the pretectal nucleus for CN III stimulation
Describe the pathway for CN III (oculomotor)?
Pupillary fibers start in the Edinger-Westphal nucleus (midbrain) -> ciliary ganglion -> eye
Which nerve and muscle provide for intorsion of the eye?
Trochlear (CN IV) and superior oblique
A patient with right superior oblique palsy (right superior oblique muscle doesn’t work) would compensate how?
Tilt head to the left
What are the branches of V3?
Auriculotemporal, long buccal, lingual, IAN, nerve to mylohyoid
What are the three major branches of V1?
Nasocilliary
Frontal
Lacrimal
What are the two branches of the frontal nerve (via V1)?
Supraorbital and supratrochlear
What type of facial paralysis would be seen if there was an upper motor neuron injury (stroke, supranuclear) to the facial nerve (CN VII)?
Contralatteral paralysis to lower face only
What type of injury is Bell’s palsy?
Lower motor neuron injury - will affect ipsilateral of whole face
Which cranial nerve opens the eye?
Oculomotor (CN III) via levator muscle
Which cranial nerve closes the eye?
Facial (CN VII) via obicularis oculi
What are the 5 sensory branches of the facial nerve?
- Temporal
- Zygomatic
- Buccal
- Mandibular
- Cervical
The greater petrosal nerve is a branch of which cranial nerve?
Facial
What types of sensory fibers are carried via the greater petrosal nerve?
Taste and parasympathetics
Where does the greater petrosal provide taste?
Palate
How does the greater petrosal provide parasympathetic innervation for lacrimation?
Superior salivatory nucleus -> greater petrosal -> pterygopalatine ganglion -> lacrimal gland
What structure does the chorda tympani pass through before joining the lingual nerve?
petrotympanic fissure
T/F: Both the chorda tympani and greater petrosal have taste and parasympathetic functions.
True
CT - ant 2/3 of tongue and salivation (submandibular and sublingual)
GP - palate and lacrimation
What is the only muscle that the glossopharyngeal (CN IX) will give motor innervation to?
Stylopharyngeal muscle
The glossopharyngeal nerve (CN IX) joins which branch of V3?
Auriculotemporal nerve
Encircles middle meningeal artery to join auriculotemporal on its way to parotid gland
What is the course of the recurrent laryngeal nerve on the right and left sides?
Right - loops around subclavian
Left - loops around aorta
Which tongue muscle is not innervated by the hypoglossal nerve (CN XII)?
Palatoglossus (CN X)
T/F: The lingual artery runs with the nerve and vein, just lateral to the hyoglossus muscle.
False
The artery is medial to the hyoglossus
Which structure is crossed twice by the lingual nerve?
Submandibular duct
All sensory info for the face is relayed through which part of the thalamus?
VPM
VPL for the body
What information goes to the spinal trigeminal nucleus?
Pain and temperature
T/F: Trigeminal fibers relaying proprioception synapse in the trigeminal ganglia.
False
Go straight to mesencephalic nucleus
Which nerve gives motor innervation to the ear?
V3
Tensor veli palatini and tensor tympani
Where are the preganglionic cell bodies of the sympathetic nervous system?
In the thoracic and lumbar regions
T/F: The sympathetic nervous system will have short preganglionic neurons that synapse at a ganglion with the longer post ganglionic neuron.
True
Parasympathetics also have pre- and post- but the preganglionic neurons are longer
Which types of neurons will release acetylcholine at the site of action?
postganglionic parasympathetic
Where do the preganglionic sympathetics for the head and neck synapse?
Superior cervical ganglion at angle of mandible
The facial nerve (greater petrosal) goes through the _________ on its way to the lacrimal gland.
pterygoid canal
Which nerve joins the greater petrosal in the pterygoid canal carrying sympathetic fibers?
nerve of the pyterygoid canal (or deep petrosal nerve) (via superior cervical ganglion)
Where are the preganglionic cell bodies for parasympathetic nerves found?
Cranial and sacral regions
What is the pathway for the glossopharyngeal nerve?
Inferior salivatory nucleus -> lesser petrosal nerve -> otic ganglion -> joins auriculotemporal nerve -> parotid gland
Which two nerves carry fibers from the nucleus ambiguus? What is the function of this nucleus?
Glossopharyngeal (CN IX) and Vagus (CN X); swallowing
Parasympathetics to the lacrimal, nasal, and palatine glands involves which ganglion?
Pterygopalatine
What are the four ganglia involved in parasympathetics to the head?
- Ciliary ganglion (CN III)
- Pterygopalatine ganglion (CN VII)
- Submandibular ganglion (CN VII)
- Otic ganglion (CN IX)
Parasympathetic fibers from CN VII pass through the pterygoid canal as the _________ to synapse with the pterygopalatine ganglion.
nerve of pterygoid canal (vidian nerve)
formed by greater petrosal (parasympathetics via CN VII) and deep petrosal (sympathetics from trunk)
Which structure does the nerve of the pterygoid canal pass over?
Foramen lacerum
Which nucleus provides parasympathetics to the abdominal and thoracic viscera via the vagus nerve (CN X)?
Dorsal motor nucleus
Afferent fibers to the glossopharyngeal nerve come from which 5 structures?
Carotid sinus, carotid body, tympanic membrane, posterior 1/3 of tongue and walls of the pharynx
T/F: The accessory nerve contains only efferent fibers.
True
The ___________ arises from the vagus nerve and divides into the internal and external laryngeal nerve.
superior laryngeal nerve
The superior laryngeal nerve arises from which ganglion?
inferior vagal ganglion
The __________ travels through the thyrohyoid membrane to supply the larynx superior to the vocal chords.
internal laryngeal nerve
Which cranial nerves supply sensory nerves to the carotid sinus?
Glossopharyngeal (IX) and Vagus (X)
The glossopharyngeal nerve innervates the stylopharyngeus with ________ fibers from _________ (which nucleus).
SVE; nucleus ambiguus
Which nerve provides motor innervation for the muscles of the vocal chords and sensory innervation for larynx inferior to the vocal chords?
Recurrent laryngeal nerve (via CN X)
The _________ is a branch of V2 that also carries parasympathetics from the facial nerve to the lacrimal gland.
zygomatic nerve
Which cranial nerve is the only one to exit the brainstem dorsally?
Trochlear nerve (IV)
also thinnest and longest cranial nerve
Where do preganglionic sympathetic nerves for the head and neck synapse?
Superior cervical ganglion (angle of mandible)
Which nerves carry parasympathetic fibers?
3, 7, 9, 10
Which nucleus provides sensory fibers for taste?
Solitary tract via CN 7, 9, 10
What is the first synapse of the optic nerve?
Lateral geniculate nucleus of thalamus (LGN)
At what point does the auriculotemporal nerve join the lesser petrosal nerve?
As it encircles the middle meningeal artery
Which branches of V1 innervate the upper eyelid?
Supraorbital and supratrochlear via frontal nerve
Which nucleus deals with swallowing?
Nucleus ambiguus via CN 9 and 10
