Module 3 Laboratory Flashcards
attach to the base of the brain, exit the cranium through its foramina, and lead to muscles and sense organs primarily in the head and neck
cranial nerves
Majority of them are “mixed” and serve both sensory and motor functions of the neck and head
cranial nerves
Few pairs are exclusively sensory and associated with special senses such as vision and hearing
cranial nerves
Others are involved in the control of muscles and glands
cranial nerves
– how many pairs of nerves leave the ventral surface of the brain
12 pairs
– numbering of cranial nerve that indicate the order in which the nerve emerges from the brain stem moving from anterior to posterior
roman numeral
cluster of neurons in each cranial nerve that integrates incoming sensory information and/or outgoing motor control
nucleus
two locations where the nuclei of cranial nerves I through IV are found
forebrain and midbrain
two locations where the nuclei of cranial nerves V through XII are found
hindbrain’s pons and medulla oblongata
cell bodies outside the brain in clusters (PNS)
ganglia
cell bodies of motor neurons are found in what matter of the brain
grey matter
cranial nerves that are strictly sensory and carry this information to the central nervous system for interpretation
cranial nerves I, II, VIII
cranial nerves that function primarily to move muscles but each has some sensory function that relays proprioception information about the state of each muscle to the central nervous system
Cranial Nerves III, IV, VI, XI, XII
mixed nerves, having both sensory and motor functions
Cranial nerves V, VII, IX, X
assessment of this is commonly done as part of a general physical examination of the head, eyes, ears, nose, throat, and neck as performed by a physician, physician’s assistant, nurse, or paramedic
cranial nerve function
- Professionals who perform a more comprehensive examination of the cranial nerve functions is usually done by specialists such as (4)
Neurologists
Ophthalmologists
Optometrist
Audiologists
- Materials used in the module 3:
- Nonirritating substance
- 10% salt solution
- 10% sugar solution
- Snellen chart
- Meter stick
- Cotton
- Cotton swab
- Tongue depressor
- Pen light
- 256 Hz tuning fork
- Reflex hammer with brush pin
subject is asked to identify with eyes closed each of the nonirritating odors
Cranial Nerve I: Olfactory Nerve
Odors should be familiar to the subject to be able to differentiate between and inability to smell substance and an inability to identify it
Each nostril is tested separately (one finger must cover the other nostril
what cranial nerve is tested
cranial nerve I
two tests are being performed to test this cranial nerve: visual acuity and visual fields
cranial nerve II: Optic Nerve
sharpness of vision when looking at near as well as distant objects using the standardized chart such as Snellen Test Letter Chart
visual acuity
measures visual acuity, which is the clearness or sharpness of vision
eye chart
distance in feet from chart
snellen chart
top number/numerator
distance at which a person with normal eyesight can read the same line
snellen chart
bottom number
Position on the subject on mark exactly ___ feet from the chart
20
If the person wears glasses or contact lenses, leave them on/off . Cover one/two eye at a time
on
one
Subject is asked to read through the chart to the smallest line of letters possible
Record the resulting numeric fraction at the end of the last successful line read
Indicate whether any letters were missed and whether corrective lenses were worn ex. O.D. 20/30 with glasses
what CN is tested
CN2
– normal visual acuity
20/20
distance the person is standing from the chart
numerator
gives the distance at which a normal eye can read a particular line
denominator
test in the visual field for Cranial nerve II that involves the positioning of the examiner at eye level with the subject and at about 2 feet away
confrontation test
One eye covered with an opaque card to look straight at the examiner with the other eye
Pencil acts as the target midline between you and the subject and slowly advance it in the periphery in several directions (upward, downward, temporally, nasally)
Ask the subject to say now as the object is first seen: this should be just as you see the object also
what CN2 test
confrontation test
tested using the observation of how much the iris is covered by the eyelid (one-third is normal value)
CN6: Abducens Nerve
Observation if ptosis is present
what CN nerve
CN6
when upper eyelid of one or both eyes droops over your eye
ptosis
Examination of the pupil includes:
If they are the same size
Round or oval?
Center of the eye facing forward or deviated to the side?
normal values of the eye include
Round
equal in size
about 2-3mm in diameter
center of the eye
check pupillary response by holding a penlight about ___cm to the side of eye and shining it directly into the pupil:
20
pupillary constriction in the eye
direct light reflex
simultaneously constriction in the untested eye
consensual eye reflex
grade based on the following:
___ (4+)
less than brisk (3+)
_____ (2+)
very slow (1+)
absent (0)
brisk
slow
move pencil from a distance of 1 m in front of the subject to within 3 cm of his or her nose. As the subject gazes at the moving object, note convergence of the eyes (the eyes become crossed) and the pupillary constriction that normally accompanies the convergence
subject is asked to cover one eye and keep his or head motionless as you move the object within the visual field about 30 cm from the eye
ask the subject to follow the pencil with his or her eye (up, down, left, right, up right, downright, up left, down left)
movement should occur precisely
what CN is tested
CN6 abducens nerve
a condition where the eyes move rapidly and uncontrollably
nystagmus
should be no nystagmus on elevation and depression of the eyes, but a small amount at the extreme of any lateral or medial gaze is normal/abnormal
normal
tested by placing the fingertips on the temporalis muscle at each temple of the subject and asking the subject to clench their teeth several times
CN6: Trigeminal nerve
Both sides should have the same strength
The strength of masseter is also tested by palpating just above and to the front of the angle of the lower jaw (contractions should be symmetrical and equal)
Opening of mouth to check if any deviation of the jaw to the right or left (normal should have no deviation)
Test the skin sensitivity to the sensitivity of light touch (cotton ball) and pain (pin prick) by telling when the stimulus is applied (eyes closed)
what CN nerve is tested
CNV: Trigeminal Nerve
strength of this is tested by asking the subject to grip a tongue depressor with his or her teeth on each side while you extract the tongue depressor (strength of closure should bilaterally be good)
jaw closure
movement of lower jaw side to side to assess this muscle function (smoothly and equally)
what muscle
pterygoid muscle
tested by pulling a piece of cotton from a cotton ball, and forming it into a long thin strand. Ask the subject to loop up and away from you, and touch the cornea with the piece of cotton, making the eyes blink (test on both eyes)
corneal reflexes
motor and sensory function is tested (motor = asking the subject to show teeth and smile, lift the eyebrows, frown, and close the eyes) (sensory (tested using a sugar or salt solution by placing a few drops on half the anterior two thirds of the tongue and instruct the subject to keep the tongue out until they have tested the substance)
CNVII: Facial Nerve
tested by Weber test or Rinne test
CNVII: Vestibulocochlear Nerve
vibrating tuning fork in the midline of the skull and hearing the tone by bone conduction (BC) through the skull
Weber test
compares air conduction (AC) and bone conduction (BC)
Rinne test
Stem of the vibrating tuning fork is placed on the mastoid process and the subject is asked to signal when the sound goes away
Fork is inverted and placed now near the end canal: the subject should still hear a sound
Normally, the sound is heard twice as long by AC (near to ear canal) as by BC (through the mastoid process)
what test
Rinne test
Positive rinne test is (AC __ BC)
greater than (>)
tested by asking the subject to open their mouth and say “ah”, noting the position of the soft palate and uvula at rest and with phonation
CNX: Vagus Nerve
Ask the subject to swallow and note any difficulty
Test for gag reflex
Test for taste on each side of the posterior one third of the tongue
what nerve
CNX: Vagus Nerve
– tested by putting one hand on the cheek of the subject and telling the subject to turn their head against your hand as you resist the movement
CN XI: Spinal accessory nerve
muscle that is palpated for the spinal accessory nerve assessment
sternocleidomastoid
Placement of hand on subject’s shoulders and testing the subject’s shrug as they attempt to elevate the shoulders while you press down with both hands
Trapezius muscle is tested
No fasciculations (happens when a single peripheral nerve that controls a muscle is overactive, resulting in involuntary muscle movement.)
what CN nerve
CNXI: Spinal accesosry nerve
tested by asking the subject to protrude their tongue to the middle, checking for deviation of the tongue tip and atrophy of the muscle in right or left of the tongue
Normally, the tip of the protruded tongue will not deviate from the midline and the tongue will appear symmetrical
what CN Nerve
CNXII: Hypoglossal nerve
- Cranial Nerves, include their function
I. Olfactory Nerve (Sensory)
II. Optic Nerve (Sensory)
III. Occulomotor Nerve (Motor)
IV. Trochlear nerve (Motor)
V. Trigeminal Nerve (Mixed)
VI. Abducens Nerve (Motor)
VII. Facial Nerve (Mixed)
VIII. Vestibulocochlear Nerve (sensory)
IX. Glossopharyngeal nerve (mixed)
X. Vagus nerve (mixed)
XI. Spinal accessory nerve (motor)
XII. Hypoglossal nerve (motor)
-tested on each side (close off other nostrils) with help of odor of common items such as coffee, soap, cloves, etc.
olfactory nerve (CNI)
abnormal findings in olfactory nerve wherein there is an inability to detect smells, as seen with frontal lobe lesion
anosmia
– testing for visual acuity with the Snellen eye chart (separate eye test at a distance of 20ft)
optic nerve
peripheral vision is tested using this wherein each quadrant is checked by asking the patient to fix his gaze straight forward and therapist showing different numbers with fingers in each quadrant which patient has to identify and detect homonymous hemianopoia
what method
confrontation method
impaired far vision
myopia
impaired near vision
presbyopia
pupillary reflex is tested by having the patient stare into the distance as the examiner shines penlight oblique into each pupil
occulomotor nerve
Abnormal findings include the absence of pupillary constrictions
occulomotor nerve damage
unequal pupillary size/shape
anisocoria
trio of nerves tested for extraocular movement
Patient is asked to look in each direction and follow moving finger in the figure of H without moving the head
Abnormal finding include strabismus (also known as hypertropia and crossed eyes — is misalignment of the eyes, causing one eye to deviate inward (esotropia) toward the nose, or outward (exotropia), while the other eye remains focused), double vision, and impaired eye movement
Oculomotor
trochlear
abducens
tested by the sensory-face function of pain, light touch sensations, cheeks, jaw on both sides
trigeminal nerve
Corneal reflex is also tested by touching the wisp of cotton in the outer corner and blinking
Abnormal findings are loss of fascial sensation, trigeminal neuralgia
Temporal and masseter muscles are palpated by having the patient clench
their teeth or hold jaw against resistance
Weakness, wasting of muscles when opened, and deviation of jaw to ipsilateral side
what nerve
trigeminal nerve
test facial muscle by raising eyebrows, frown, show teeth, smile, close eyes tightly, puff out both cheeks
facial nerve
Abnormal findings include the inability to close eye, drooping corner of mouth, difficulty with speech articulation
Sensory is tested by applying saline solution and sugar solution using a cotton swab
facial nerve testing
testing eye-head coordination: vestibular ocular reflex (VOR) with the patient’s eye fixed rotation of head by 20 degrees and take back to midline rapidly (look for movement of eyes)
vestibulocochlear nerve
Abnormal findings include vertigo, disequilibrium, gaze instability with head rotation and nystagmus
vestibulocochlear testing
function for phonation and swallowing, listening to voice quality, palatal and pharyngeal control
2 nerves
glossopharyngeal
vagus nerve
(hoarseness denoted in vocal cord weakness)
dysphonia
difficulty swallowing
dysphagia
Abnormalities in palatal control include the failure to elevate-lesion of CN 10; and asymmetrical elevation with unilateral paralysis
what cn
vagus nerve
– stimulate the back of the throat lightly on each side reflex contraction of back and throat to remove the stimulus out
gag reflex
Abnormal findings include absent reflex (lesion of CN9 and possibly 10)
gag reflex
test the bulk of trapezium muscle (bulk and shrug)
spinal accessory nerve
Abnormal finding include atrophy, fasciculation, and ipsilateral weakness (bulk)
Abnormal finding include inability to shrug ipsilateral shoulder, shoulder droop
spinal accesory nerve
checked for bulk and strength (turn each side against resistance for checking of strength of muscle on opposite side)
Abnormal findings include the inability to turn the head opposite side, weakness of ipsilateral sternocleidomastoid and contralateral trapezius
sternocleidomastoid muscle
tongue movement is observed by listening to patient’s articulation (abnormal = dysarthria, difficulty speaking)
hypoglossal nerve
first cranial nerve
Originates in cerebrum and olfactory epithelium
Function in smell
2 main braches in superior nasal concha and nasal septum
olfactory nerve
second cranial nerve and contains only afferent fibers
Originate in cerebrum and optic disk
Function in sensory information
Damage to this nerve can cause loss of vision
optic nerve
third cranial nerve that controls four muscles in the eye
Originate in the oculomotor nucleus, midbrain
Function in eye movement
Damage can cause deficits in in the ipsilateral eye
what nerve
CNIII: occulomotor nerve
responsible to make the eye move/look down
Originate in the midbrain, trochlear nucleus
Function in eye movement in the superior oblique muscle
Shortest cranial nerve
trochlear nerve
largest of the cranial nerves
Largest of the cranial nerves
Originate in the midbrain, pons, medulla, upper spinal cord
Function in sensory and motor
trigeminal nerve
3 main branches of trigeminal nerve include
ophthalmic
maxillary
mandibular
– originate in the pons, function in the lateral movement of the eye and works with the oculomotor nerve (CN III) and trochlear nerve (CN IV)
Abducts the lateral rectus muscle
Abducens nerve palsy
abducens nerve
originate in the brain stem which function in motor (facial expression) and sensory (innervates external auditory meatus, tympanic membrane, and pinna of the ear)
Taste and parasympathetic fibers (supply glands)
facial nerves
Emerges from the brainstem between the pons and medulla composed of two nerves that functions for sensory purposes
auditory/vestibulocochlear nerve
equilibrium
auditory/vestibulocochlear
hearing
cochelar
cranial nerve 9 that originate in the medulla oblongata
Targets pharynx, tonsils, posterior tongue, parotid gland, and carotid artery
Functions in sensory (taste for posterior 1/3 of tongue) and motor functions (stylopharyngeus muscle promoting swallowing and saliva production)
glossopharyngeal nerve
cranial nerve 10, which means “wandering”, originate in the medulla oblongata
Target pharynx, larynx, epiglottis, thoracic, and abdominal viscera
Mixed nerve: sensory (special sensory) and motor (parasympathetic) functions
Digestive activity, respiration of the lungs, swallowing, heart rate
Other functions are immune responses, mood, mucus and saliva production, skin and muscle sensations, speech, taste, urine outpu
vagus nerve
originate in the cranial (medulla) and spinal (cervical spinal cord)
Also known as the spinal accessory nerve
accessory nerve
Travels with the vagus nerve, controlling muscles of pharynx, palate, and larynx
what portion of spinal accessory nerve
cranial
Travels to sternocleidomastoid and trapezius muscles
what portion of spinal accessory nerve
spinal
Facilitates head movements and neck flexion
what muscle
sternocleidomastoid
Involved in neck and shoulder movements, including shrugging and raising arms
what muscle
trapezius
originate in the medulla oblongata, purely motor nerve, controls all muscles of the tongue (except palatoglossus(
hypo means under and glossal means tongue
divided into intrinsic muscles and extrinsic muscles
intrinsic muscles include superior longitudinal, inferior longitudinal, transverse, vertical
extrinsic muscles include genioglossus (bulk of the tongue), hyoglossus, styloglossus
hypoglossal nerve
