cranial Nerves Flashcards
How many pairs of cranial nerves do we have?
12
what is innervated by nerves that provide general somatic innervation?
skin and muscles
what is innervated by nerves that provide general visceral innervation?
Blood vessels, salivary glands, intraocular muscles
what is innervated by nerves that provide special somatic innervation?
Vision, hearing, balance
what is innervated by nerves that provide special visceral innervation?
taste and smell
what are the false cranial nerves? why?
cranial N 1 and 2
Extension of brain tissue developmentally
what is the name of Cranial N 1
olfactory
what is the name of Cranial N 2
optic
what is the name of Cranial N 3
occulomotor
what is the name of Cranial N 4
trochlear
what is the name of Cranial N 5
trigeminal
what are the 3 subnerves of cranial N 5
V1: opthlamic N
V2: maxillary N
V3: mandibular N.
what is the name of Cranial N 6
abducens
what is the name of Cranial N 7
facial
what is the name of Cranial N 8
vestibular/auditory
what is the name of Cranial N 9
glossopharyngeal
what is the name of Cranial N 10
vagus
what is the name of Cranial N 11
spinal acessory N
what is the name of Cranial N 12
hypoglossal
what cranial N originate from the brain?
1 and 2
what cranial N originate from the midbrain?
occulomotor and trochlear
what is a particular characteristic of the origin of the throchear N?
originates at Midbrain from posterior and wraps anteriorly
what cranial N originate from the PONS?
5
what cranial N originate from the pontomedullary junction?
6,7,8
what cranial N originate from the Medulla
9,10,11, 12
what cranial N originate from the medulla and spinal cord?
11
what cranial N passes through the cribiform foramen of the ethmoid bone?
olfactory N. (1)
what cranial N passes through the optic canal of the sphenoid bone?
Optic N. (2)
what cranial N passes through the SOF?
occulomotor (3)
Trochlear (4)
Opthlamic N (V1)
Abducens (6)
what cranial N passes through the foramen rotundum?
Maxillary N (V2)
what cranial N passes through the foramen ovale
Mandibular N (V3)
what cranial N passes through the stylomastoid foramen?
Facial N (7)
what cranial N passes through the internal accoustic meatus?
Vestibular N (8)
what cranial N passes through the jugular foramen?
glossopharyngeal (9)
Vagus (10)
spinal accessory (11)
what cranial N passes through the hypoglossal canal?
hypoglossal N (12)
what Nerves go around the PONS of the brainstem?
4-5-6
how do nerves 7-11 travel relative to the brainstem?
goes straight down along the medulla oblongata
how does the 12th nerve travel relative to the brainstem?
curls back at the center
what nerve is responsible for the motor innervation of the tongue?
XII- hypoglossal
what nerve is responsible for the motor innervation of the Trapezius and sternocleidomastoid?
XI- Spinal accessory
what nerve is responsible for the motor innervation larynx and phalynx?
X- Vagus
what nerve is responsible for the sensory innervation of the posterior 1/3 tongue
X- Vagus
what nerve is responsible for the parasympathetic innervation of the salivary glands?
X- Vagus
what nerve is responsible for the sensory innervation of the hearing and balance?
VIII- Vestibular (auditory)
what nerve is responsible for the sensory innervation of the taste to anterior 2/3 of the tongue?
VII- Facial
what nerve is responsible for the parasympathetic innervation of the lacrimal and salivary glands?
VII- Facial
what nerve is responsible for the motor innervation of the muscles of facial expression?
VII- Facial
what nerve is responsible for the motor innervation of the LR
VI- Abducens
what nerve is responsible for the motor innervation of the muscles of mastication?
V3- mandibular N.
what nerve is responsible for the sensory innervation of the upper, middle and lower face?
V- Trigeminal
V1: opthlamic N
V2: maxillary N
V3: mandibular N.
what nerve is responsible for the motor innervation of the SO?
IV- Trochlear
what nerve is responsible for the motor innervation of the : Extraocular muscles of the eye (superior, inferior and medial rectus and inferior oblique)?
III- Occulomotor
what nerve is responsible for the parasympathetic innervation of the iris and is involved in pupillary construction
III- Occulomotor
what nerve is responsible for vision?
II- Optic
what nerve is responsible for smell?I- Olfactory
I- Olfactory
what parts compose the brainstem?
midbrain
PONS
medulla oblongata
what is the nerve pathway of the olfactory N?
Small N. fibers dangling in the nasal cavity, begin in nose epithelium.` The nerve pierces through the cribriform plate and consolidates in the olfactory bulb which represents cranial N. I which narrows into olfactory track and brings simulation of what we smell
where is the olfactory bulb located?
Bulb sits directly in the cribiform foramena
what is the nerve pathway of the optic N
Optic nerve–> optic chiasm–> optic tract (crossing)
where is the pituitary gland located relative to the optic chiasm? what fossa is there?
Pituitary gland sits posterior to the optic chiasms (and where hypophyseal fossa)
where does the right Visual field project?
left brain
where does the left visual field project?
right brain
what muscles elevates the upper eye lid?
• Levator palpebrae superioris
what is the insertion and origin of Levator palpebrae superioris
Originate at common tendinous ring
Inserts at upper eye lid
what is the insertion and origin of the 4 rectus muscles?
originate along the anterior half of the eye ball and insert onto the common tendinous ring (annulus of zinn)
what is the annulus of zinn?
ring where all ocular muscles originate
what is the function of Superior rectus?
elevation + intorsion
what is the function of rectus inferior?
depression and extorsion
what is the function of medial rectus?
adduction of the eye
what is the function of lateral rectus?
abduction of the eye
what muscle allows for depression and intorsion of the eye?
superior oblique
where does the contraction of the superior oblique come from?
Contraction comes from back of top of eye ball and moves forward
what is the sling along the medial orbit known as?
trochlea
where does the superior oblique insert?
on the annulus of zinn
what muscle of the eye allows for elevation and extorsion?
inferior oblique
where does the inferior oblique insert?
Inserts on medial wall of the orbit
what happens to the optical axis during gaze?
it changes as different muscles work together
what muscles of the eyes are used in order to look to the left?
Right eye medial rectus, left eye lateral rectus
what muscles work together in order to get complete elevation of the eye?
IO and SR
what muscles work together in order to get complete depression of the eye?
IR and SO
what must be done to MR and LR to test for adductor/abductor of the eye?
- Lateral rectus – ask patient to look away/laterally (abduct the eye)
- Medial rectus – ask patient to look towards their nose (adduct the eye)
what must be done to SR and IO to test for elevation of the eye?
- Superior rectus – ask patient to abduct the eye and look up
- Inferior oblique – ask patient to adduct the eye and look up
what must be done to IR and SO to test for depression of the eye?
- Inferior rectus – ask the patient to abduct the eye and look down
- Superior oblique – ask patient to adduct the eye and look down
which root (sensory or motor) of the Trigeminal N is greater in size?
sensory root
what does the opthalmic branch (V1) innervate?
Sensation to the skin of the forehead, upper eye lid and center portion of the nose
what does the maxillary branch (V2) innervate?
sensation from upper eye lid to middle of the lips (middle face
what nerve arises from the CN V2? which foramen does it exit?
infraorbital N.
exits via infraorbital foramen
what is the innervation provided by the mandibular branch (V3)?
Sensation to the lower face to the chin from the superior border of upper lip
what branches arise from the mandibular branch?
inferior alveolar N
lingual N.
what is innervated by the lingual N.?
General sensory Innervation to the anterior 2/3 of the tongue
where does the inferior alveolar N. peak out of? what does it become?
Mental Foramen
becomes the mental N
what is the function of the mental N.?
which provides innervation to the skin of the inferior face (inferior border of upper lip to chin)
what is the function of the inferior alveolar N?
provides sensation to the lower teeth.
what passes through foramen spinosum?
meningeal A
what does the facial N. pierce as it exits the stylomastoid foramen?
the parotid gland
into how many branches does the facial N. divide into?
5 groups
what branches does the facial N give rise to?
- corda tympani branch
- parasympathetic fibers
what is innervated by the parasympathetic fibers of the facial N?
- lacrimal gland
- nose
- palate
what is innervated by the corda tympani branch?
- sublingual gland
- submandibular gland
what does the corda tympani merge into?
lingual N.
what is the function of the corda tympani branch?
Special sense of taste: anterior 2/3 of the tongue
what does the auditory nerve branch into?
cochlear branch (hearing) vestibular branch (balance)
what nerve passes through the tongue and pharynx?
Glossopharyngeal N.
what is the function of the glosso portion of the glossopharyngeal N?
• Sensory general and special (taste): to the posterior ½ of the tongue
what is the motor innervation of the glossopharyngeal N. responsible for?
control of the muscles involved with swallowing
what N. is responsible for the parasympathetic innervation of the parotid gland?
glossopharyngeal N
how does the vagus nerve travel through the body?
travels between the internal jugular vein and the common cartoid A.
what nerve does the vagus nerve merge with?
the cranial root of CN X1
what are the branches in the neck that originate from the vagus nerve?
- laryngeal recurrent n
- branches to the pharynx
what is the function of the recurrent larygeal N?
Motor innervation to the vocal cords
do the R/L recurrent larygeal N pass by the same pathways?
no, they have different pathways
what nerve provides parasympathetic innervation to the o Cardiac plexus o Pulmonary plexus o Esophageal plexus o Foregut & midgut
vagus N.
what nerve provides sensory innervation to the larynx?
vagus N.
how does the CN XI spinal portion merge with its cranial portion?
spinal contribution enters the skull via foramen magnum and will merge with the cranial portion which arises from the brainstem
what does the spinal root of CN XI stem from?
Stems from upper 5 cervical spinal cord
how does the spinal root of CN XI exit the skull?
Exits the skull and descends along the posterior sternocleidomastoid and passes
what is the motor innervation provided by the CN XI?
Trapezius
Sternocleidomastoid muscles
what is innervated by the hypoglossal N?
Intrinsic muscles of the tongue
how is the tongue innervated?
bilaterally, hence Right brain controls left tongue and vice versa
