Cranial Nerves

cranial nerves that emerge from the brain itself.

cranial nerves that emerge at the level of the midbrain.

cranial nerves that emerge at the level of the pons.

cranial nerve that emerge at the level of the medulla oblongata.

for general sensations.

for hearing, balance, and vision.

for viscera; sensation of the internal organs.

for smell, taste.

for somatic striated muscle.

for glands and smooth muscles; parasympathetic innervation.

for branchial arch striated muscles.

- located above the cribriform plate at the ethmoid bone

- contains follicles where sensory input travels from the mucosa of the nose

- at the hippocampal gyrus

- have the ability to store different emotional reactions to the specific olfactory sensations that one perceives

cells in the olfactory bulb.

penetrates in the cribriform plate of the ethmoid bone and synapses with the cells in the olfactory bulb to transfer olfactory sensation from the receptor to the bulb itself and to the olfactory tract.

divided into the medial and lateral stria.

division of lateral stria of the olfactory tract.

subserves the primary olfactory area.

subserves the secondary olfactory area.

its main function is the sense of smell.

test for olfactory nerve.

- inability to differentiate specific scent

- frontal lobe lesion

- seen most commonly when there is a traumatic injury (coup-contrecoup injury)

- may be ipsilateral or bilateral

occurs when there is a frontal bone fracture.

- leak of CSF in cavernous sinus; sweet in taste

- may also be pinkish due to blood

blurred vision due to old age.

secondary visual cortex.

affected is the primary visual cortex.

- pure sensory cranial nerve

- function is for vision alone

test for optic nerve.

standard test used for visual acuity test.

what reading considered legally blind.

common visual eye field can be divided into these:

cranial nerve for automatic pupillary constriction.

purpose of this test is to know if pt can see the light.

patient’s eye constricts as the object approaches the eye.

two nucleus concerned for pupillary light reflex.

constriction of the ipsilateral pupil; adjacent to the stimuli.

constriction of the contralateral pupil; opposite to the stimuli.

T/F if the optic nerve is affected, both the (L) and (R) direct and consensual light reflex is affected.

- (+) pupil constriction to accommodation

- (-) pupil constriction to light reflex

unequal pupillary constriction.

- pure motor

- two motor nuclei:

• Main motor nuclei/somatic - voluntary

• Accessory parasympathetic nucleus/parasympathetic - involuntary

- turns the eye up, down, and in and elevates the eyelid

- subserves all the extraocular muscles except for superior oblique and lateral rectus

- exotropia

- lateral deviation of the eyeball

drooping of the upper eyelid.

tests for oculomotor nerve.

cranial nerves concerned for visual tracking.

- the most slender of the cranial nerves and the only one to leave the posterior surface of the brainstem

- turns adducted eye down

- subserves superior oblique

test for trochlear nerve.

- has to tilt the head in order to align the eyes

- cannot turn eyes downward and inward

- pt looks upward; only inferior oblique moves

when this muscle is affected the patient has great difficulty in turning the eye downward and laterally.

- mixed; sensory and motor

- motor:

• muscles of mastication

• tensor tympani

• tensor veli palatini

• mylohyoid

• anterior belly of the digastric muscle

- sensory:

• sensations of face

• sensation of the mouth and tongue

• sensation of the cornea (test: corneal reflex)

three branches of the trigeminal nerve.

- sensory fibers only and exits at the superior orbital fissure

- subserves upper portion, most of the forehead to the nose

- sensory fibers only and exits at the foramen rotundum

- subserves upper lip

- sensory and motor fibers; exits at foramen ovale

- subserves lower lip and jaw

muscles that is subserved by the trigeminal nerve that regulates the amount of sound that enters the ear.

tests for trigeminal nerve.

- tic douloureux

- abnormal pain sensation on the trigeminal nerve distribution (commonly: V2 and V3)

cranial nerves that is concerned with corneal reflex.

- longest intracranial nerve

- responsible in giving motor control to lateral rectus

- esotropia

- medial deviation of the eyeball

test for abducens nerve.

- mixed type of nerve

- controls muscle of facial expression, stapedius muscle, and digastric muscle

- parasympathetic: salivary and lacrimal glands

- visceral: anterior 2/3 of the tongue

- somatic: small region of the external ear

divisions of the facial nerve.

areas wherein the facial nerve travels/go through.

division of the facial nerve concerned with parasympathetic functions (salivary and lacrimal).

- increased sensitivity to sounds

- can be unilateral or bilateral

- due to paralysis/weakness of the muscles if facial expression

- accumulation of saliva

test for taste sensation of facial nerve.

two components of the vestibulocochlear.

test for vestibular.

occurs when there is a problem within the cochlea or the neural pathway to the auditory cortex.

occurs when sound is impeded through the external ear, the middle ear, or both.

used to differentiate bone and air conduction.

sound travel via bone.

sound travel via air.

used to test bone conduction alone.

alternative test if there is no tuning fork.

- lest sensitivity; not commonly used

- alternate placing of the tuning fork on the mastoid process of both pt and PT

=largest motor component: stylopharyngeus

- parasympathetic: parotid glands

- somatic: middle ear

- visceral sensory:

• special: posterior 1/3 of the tongue

• general chemoreceptors and baroreceptors of carotid body

- gustatory nuclei/cardiorespiratory nucleus

- nuclei which orginate branch of glossopharyngeal nerve that supplies chemoreceptors and baroreceptors

- divided into:

• caudal - cardiorespiratory nucleus

• rostral - gustatory nucleus (posterior 1/3 of the tongue)

- one of the longest cranial nerve; has lot of visceral functions

- general sensation: external ear

- responsible parasympathetic and sympathetic of visceral organ and movement of uvula

- motor for gag reflex

- least likely to be injured; once it is injured, it can be life threathening

muscle that moves the uvula.

test for vagus nerve.

subserves trapezius and SCM

test for accessory nerve.

controls voluntary pushing motion of the tongue and retraction.

test for hypoglossal nerve.

signs that there is a problem with hypoglossal nerve.