Anatomy of cranial nerves Flashcards
What cranial nerves come from the forebrain?
CNI and II
What cranial nerves come from midbrain?
CNIII and IV
Which cranial nerve comes from pons?
CNV
Whhich cranial nerves come from the ponto-medullary junction?
CN VI, VII and VIII
What CNs come from the medullar?
IX, X and XII
What CNs come from the psinal cord?
XI
What separates the middle and psoterior cranial fossae?
ridge of petrous temproal bone and tentorium cerebelli
What CNs can be visualised at the ridge of the petrous temproal bone?
CNs III, IV and V
What division of the trigeminal nerve carries both sensory and motor fibres?
mandibular
What foramen does CNV1 travel through?
SOF
What foramen does CNV2 travel through?
foramen rotundum
What foramen does CNV3 travel through?
foramen ovale
What is the superficial sensory distribution of CNV1?
upper eyelid; cornea; all conjunctiva; root/bridge/tip of nose
What is the superficial sensory distribution of CNV2?
lower eyelid; skin over maxilla; ala of nose; upper lip
What is the superficial sensory distribtion of CNV3?
skin over mandible and TMJ
What nerve supplies the angle of the mandible?
great auricular nerve
What is the deep sensory innervation of CNV1?
bones and soft tissues of orbit(except floor); upper ant. nasal cavity; paranasal sinsues (except antrum); anterior and posterior cranial fossae
What is the deep sensory innervation of CNV2?
lower posteiror nasal cavity; maxilla and antrum; floor od nasal cavity/palate; maxillary teeth and assoc. soft tissue
What is the deep sensory innervation of CNV3?
middle cranial fossa; mandible; anterior 2/3rds of tongue; floor of mouth; buccal mucosa; mandibular teeth and assoc. soft tissues
Where is the trigeminal sensory ganglion located?
middle cranial fossa
What are the 3 pairs of jaw closing muscles?
massseter; temporalis and medial pterygoid
What are the attachments of masseter?
angle of mandible to sygomatic arch
What are the attachments of temporalis?
coronoid process of mandible to lateral aspect of cranium
What are the attachments of medial pterygoid?
angle of mandible to ptyerygoid plates of sphenoid
What is the jaw opening muscle?
lateral pterygoid
What are the attachemnts of lateral ptyerygoid?
condyle of mandible and articular disc of TMJ to pterygoid plates of sphenoid
Where does the facial nerve exit the skull?
stylomastoid foramen
How does the facial nerve trave lfrom the IAM to the stylomastoid foramen?
through the facial canal in petrous temporal bone
What branch does the facial nerve give off in the middle ear?
chorda tympani
What does chorda tympani carry?
taste; parasymp to salivary glands
What is the function of stapedius?
protects internal ear against excessive noise
what is the function of tensor tympani?
dampens noise produced by chewing
What nerve does the chorda tympani join with?
lingual nerve (CNV3)
What does the muscles of facial expression orginiate and insert onto?
originiate on bone and insert into superficial fascia
What are the 4 muscles of facial expression?
frontalis; orbicularis oculi; elevators of lips; orbicularis oris
What are the 5 branches of facial nerve to facial expression?
temporal; zygomatic; buccal; marginal mandibular; cervical
What muscle is located deep to the buccal fat pad?
buccinator
What nerve forms the afferent limb of the gag reflex?
CNIX
What is the general sensory distribution of CNIX?
post. 1/3rd tongue; nasopharynx; oropharynx and som larygnopharynx; palatine tonsil; eustachian tube and middle ear cavity
What ar ethe visceral afferents carried by CNIX?
carotid sinus baroreceptors and carotid body chemoreceptors
What is the special sensory in CNIX?
to vallate papillae of post 1/3rd of tongue
How does the vagus nerve travel down the neck?
in the carotid sheath
Aside from the vagus nerve, what travels in the carotid sheath?
IJV; CCA and deep cervical lymph nodes
What is the difference between the right and left vagus nerves in the thorax?
right travles on the lateral aspect of the trachea and the left travels on the lateral aspecto f the aortic arch
Do the vagus nerves pass anterior or posterior to the lung root?
posterior
How far along the GI tract doe vagus innervate?
splenic flexure of the colon
After the surface of the stomach where do the vagus nerves go next?
celiac and superior mesenteric ganglia
How does the spinal accessory enter the cranial cavity?
through foramen magnum
How does the spinal accessory exit the skull?
jugular foramen
Where does spinal accessory travel once out of the jugular foramen?
travels deep to SCM then across the posterior trangle of neck and supply trapezius-deep to it
What is the difference between the cervical plexus and spinal accessory given they all pass the nerve point?
cervical plexus doesnt pass deep to trapezius whereas spinal accessory does
At what level does the hypoglossal go anterior to the tongue?
hyoid bone
How does the hypoglossal nerve travel down the neck?
lateral to the carotid sheath
How is the optic nerve tested?
light reflexes; visual fields; snellen
How is trigeminal nerve tested?
facial sensations; powero f muscles of mastication
How is facial nerve tested?
power of muscles of facial expression
How is the vagus nerve tested?
elevation of soft palate; normal swallow and speech
How is spinal accessory tested?
turning of head and shrugging shoudlers
How is hypoglossal tested?
protusion of the tongue
Which cranial nerve exits posteriorly?
IV
Which cranial nerve exits laterally?
VIII
Which nerve is the only sensory modality that doesn’t synapse in the thalamus before the cortex?
CNI
What cranial nerve nuclei are found in the midline?
III, IV and VI
Where is Edinger-Westphal nucleus located?
superior colliculus
Where is trochlear nucleus located?
inferior colliculus
Where is the VI nuclei found?
floor of the 4th ventricle
What is the function of the mesencephalic nucleus?
proprioception info from chewing muscles
what is the function of the pontine trigeminal nucleus?
discriminative touch, vibration
Waht is the function of the spinal nucleus?
pain and temp
what are the 3 part s of the sensory nucleus of trigeminal?
mesencephalic; pontine trigeminal nucleus; spinal nucleus
What is unusual about the mesencephalic nucleus?
only site in CNS where cell bodies of primary afferent nueurones are in CNS
How do fibres from the facial motor nucleus leave the brainstem?
curve posteriorly around abducens nucleus
What is the function of the solitary nucleus?
taste
What is the function of the commisural nucleus?
visceral information
What is the modality of nucleus ambiguus?
motor to palate, pharynx and larynx
Which cranial nerves contribute to the solitary and commisural nuclei?
VII; IX and X
Where is the solitary nucleus?
upper and lower medulla
What is the function of the corticobulbar tract?
part of pyramidal tract that is motor to cranial nerves
Where is the parasympathetic imput to the cranial nerves from?
hypothalamus