cranial nerves Flashcards
only CN to attach to the pons
trigeminal nerve
intracranial course of the trigeminal nerve
inferior to the edge of the tentorium cerebelli between the posterior and middle cranial fossae
which foramen does CNV1 enter
superior orbital fissure
which foramen does CNV2 enter
foramen rotundum
which foramen does CNV3 enter
foramen ovale
superficial sensory innervation of the ophthalmic nerve
the upper eyelid
the cornea
the conjunctiva
the skin of the root/bridge/tip of the nose
superficial sensory innervation of the maxillary nerve
the skin of the lower eyelid
the skin over the maxilla
the skin of the ala of the nose
the skin/mucosa of the upper lip
superficial sensory innervation of the mandibular nerve
skin over the mandible and temporomandibular joint (not angle of the mandible)
function of CNIII
eye movements (MR, IO, SR, IR)
pupil constriction
accommodation reflex
eyelid opening
palsy of CNIII
ptosis
down and out
dilated, fixed pupil
foramen that CNIII passes through
superior orbital fissure
trigeminal nerve motor innvervation
3 pairs of jaw closing muscles: masseter, temporalis, medial pterygoid
1 pair of jaw opening muscles: lateral pterygoid
also: tensor veli palatini, tensor tympani
sensory test of ophthalmic nerve
forehead
upper eyelid and tip of the nose
sensory testing of maxillary nerve
mid-cheek, lower eyelid, upper lip and nostril of nose
sensory testing of mandibular nerve
mid-cheek, lower lip and chin
motor testing of trigeminal nerve
palpate the strength of contraction of the masseter and temporalis by asking the patient to clench their teeth
ask the patient to open their jaw against resistance
connection to the CNS for the facial nerve
anterolateral at pontomedullary junction
intracranial part of the course of the facial nerve
directly into internal acoustic meatus in the posterior cranial fossa
extracranial part of the course of the facial
most somatic motor axons pass into the parotid gland then into 1 of the 5 branches that supple the muscles of facial expression
chorda tympani is a branch of what nerve
CNVII
what does the chorda tympani innervate
taste buds of the anterior 2/3rds of the tongue
parasympathetic supply to the submandibular and sublingual salivary glands
the tiniest skeletal muscle in the body
stapedius
what nerve innervates the stapedius
CNVII
what does the stapedius do
reduces stapes movement to protect the internal ear from excessive noise
clinically test motor function of facial nerve by asking patient to
frown
close eyes tightly
smile
puff out cheeks
glossopharyngeal connection to the CNS
lateral aspect of superior medulla oblongata
intracranial part of the course of the glossopharyngeal nerve
directly towards jugular foramen in the posterior cranial fossa
extracranial part of the course of the glossopharyngeal
axons mainly pass to or from the tongue and palate
special sensory function of glossopharyngeal
the vallate papillae (with taste buds) of the posterior 1/3rd of the tongue
parasympathetic function of glossopharyngeal
to the parotid salivary gland
afferent limb of the gag reflex
CNIX
general sensory function of glossopharyngeal
the posterior 1/3rd of the tongue
mucosa of most of the nasopharynx
mucosa of all of the oropharynx
mucosa of some of the laryngopharynx
palatine tonsil
eustachian tube
middle ear cavity
vagus nerve connection to CNS
lateral aspect of medulla oblongata, immediately inferior to CNIX
intracranial part of the course of the vagus nerve
directly towards jugular foramen in the posterior cranial fossa
extracranial part of course of vagus nerve
axons supply lots of structures between the palate and the midgut
course of the vagus nerve in the chest
right CNX runs along lateral aspect of trachea
left CNX runs along lateral aspect of aortic arch
clinical testing of the vagus nerve
ask patient to say ah- also test CNV3
- uvula should lift straight up in midline
- deviates away from the lesion
ask patient to swallow small amount of water
- watch larynx
listen to speech: hoarseness
ask patient to cough
spinal accessory nerve connection to CNS
via cervical spinal nerve anterior rootlets to the spinal cord
intracranial part of the course of the spinal accessory nerve
ascends through foramen magnum then travels towards jugular foramen in posterior cranial fossa
which foramen does the spinal accessory nerve pass through
jugular foramen
extracranial part of the course of the spinal accessory nerve
axons supply sternocleidomastoid on deep surface, then continue across posterior triangle of the neck deep to investing fascia and supply the trapezius
clinical testing of spinal accessory nerve
ask patient to shrug shoulders
ask them to turn head to look up towards the opposite side
hypoglossal nerve connection to CNS
via many rootlets that attach lateral to the pyramids of the medulla oblongata
intracranial part of the course of the hypoglossal nerve
passes anteriorly towards hypoglossal canal in the posterior cranial fossa
which foramen does the hypoglossal nerve pass through
hypoglossal canal
extracranial part of the course of the hypoglossal nerve
descends in neck lateral to carotid sheath
at level of hyoid bone it passes anteriorly towards the lateral aspect of the tongue
supplies most of the muscles of the tongue
clinical testing of the hypoglossal nerve
ask patient to stick tongue straight out
- tongue will point towards side of lesion
clinical testing of the optic nerve
light reflexes, visual field testing, snellen chart
oculomotor testing of cranial nerves
extraocular eye movements
