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Cranial Nerves
- 12 pairs of nerves in the peripheral nervous system2) Serve four general sensory functions and motor functions3) Regulates (1) vision, (2) audition, (3) olfaction, (4) gestation, and (5) speech4) canhave sensory, motor, or mixed nerves5) most cranial nerve nuclei (where they begin)are located in the ventricular floor of the brainstem- Bilateral- Paired- Contralateral TERM 2
What are the Cranial Nerves in order and by
name?
DEFINITION 2 I On.Olfactory XI At AccessoryII Old Optic XII Hops. HypoglossalIII Olympus OculomotorIV ToweringTrochlearV Tops. *TrigeminalVI A AbducensVII Fin FacialVIII And. Auditory/Vestibulocochlear IX GermanGlossopharyngeal X Vended Vagus TERM 3
I. Olfactory Nerve
DEFINITION 3 Sensory Nerves Ages 60-65, begin to lose sense of smell Anosmia Hyperosmia Hyposmia Bilateral lesions have a drastic effect on sense of smell *smell directly related to tastes, so older people eat less TERM 4
Anosmia
DEFINITION 4 Inability to perceive smell, odor. Can also affect loss of taste TERM 5
Hyperosmia
DEFINITION 5 Abnormally acute sense of smell; heightened sense of smell
Hyposmia
Decreased olfactory sensation (sense of smell) TERM 7
II. Optic
DEFINITION 7 Sensory Selected visual field loss Lesion of entire optic nerve would result in complete blindness *she is not very interested in this. TERM 8
III. Oculomotor
DEFINITION 8 Motor Nerves Traumatic Brain Injury (TBI) Ptosis (drooping eye lids) Strabismus (cross-eyed; lazy eye), affects peripheral vision, genetic TERM 9
IV. Trochlear
DEFINITION 9 Motor NervesIf damaged, weakness or paralysis of the superior oblique muscle (eye) Diplopia (double vision) TERM 10
V. Trigeminal
DEFINITION 10 Mixed - sensory and motor nervesHas three sensory branches: Ophthalmic Maxillary Mandibular
Mandibular
Branch
** Largest branchMediates sensation from Skin on the sides of the scalp Lower gums Mouth External auditory meats External surface of the tympanic membrane Anterior two thirds of the tongue TERM 17
What are sensory clinical correlates of Cranial
Nerve V?
DEFINITION 17 Ipsilateral loss of sensation in the area of distribution of the nerve Loss of sneezing and blinking reflex Trigeminal neuralgia (usually ophthalmic or Mandibular branch) Intense and stabbing pain involving one or more branches TERM 18
What are motor clinical correlates of Cranial
Nerve V?
DEFINITION 18 Flaccid paresis or paralysis of the ipsilateral muscles of mastication Muscle atrophy (waste away) Jaw deviates to the side of injury (exaggerated jaw protrusion) Bilateral lesions cause marked paralysis of the mastication, bilaterally the mandible hangs low - causes difficulty in the production of vowels and labial and lingual consonant sounds TERM 19
VI. Abducens
DEFINITION 19 Motor NervesContributes to ocular movementsDamage = Medial Strabismus (cross eyed) TERM 20
VII. Facial
Nerve
DEFINITION 20 Mixed - Sensory and Motor NervesPrimarily motorMotor nerve for the muscles of facial expressionsStapedius muscle (in the ear)Small sensory component Taste sensation from the anterior two thirds of the tongue and nasopharynx
VIII. Auditory
Vestibulocochlear Sensory nerves Mediates head position (equilibrium) in space If damages, affects hearing TERM 22
IX. Glossopharyngeal Nerve
DEFINITION 22 Mixed - Sensory and Motor NervesMediates: (1)touch, (2) pain,(3) tension, (4) temperature from upper pharynx, tonsils, Eustachian tube, middle ear cavity, soft palate (intraoral structures)Taste info from posterior third of the tongue!Contributes to swallowing TERM 23
What are clinical correlates of Cranial Nerve
IX?
DEFINITION 23 Lesion is rare. Partial paresis of the unilateral stylopharyngeal muscleImpairing the ipsilateral pharyngeal elevationLoss of gag reflexExcessive oral secretion TERM 24
X. Vagus
DEFINITION 24 Mixed - Sensory and MotorA.K.A. WandererMost extensive distribution90% sensory 10 % motorControls muscles used for probation and swallowingInnervate cardiac muscles, smooth muscles of th esophagus, stomach, intestine, muscles of the pharynx and larynxSensation of paint, touch, pressure from mucosa of the pharynx, epiglottis, trachea, bronchi, esophagus and stomachRegulates cardiovascular, respiratory and gastrointestinal functions TERM 25
What are clinical correlates of Cranial Nerve
X?
DEFINITION 25 Unilateral lesion of the Pharyngeal branch results in ipsilateral paresis or paralysis of the soft palate, pharynx, and larynxDysphagiaParalysis of the levator muscle of the soft palateSoft palate lowers on the affected side and uvula is pulled to the unaffected side. Coronary circulation disorders, heart rate and relaxation Paralysis of the vocal folds Choking and pulmonary aspirationIf bilateral, will have aphonia and inspiratory stridor
Weber
Mid brain lesion Primarily affects oculomotor nerve Contralateral hemiplegia Ipsilateral ocular paralysis Ptosis (drooping eyelid) Pupil dilation Lateral deviation of the ipsilateral eye TERM 32
Millard-Gubler
DEFINITION 32 Lower pons lesion Facial nerve Descending motor fibers Marked contralateral hemiplegia Ipsilateral facial paralysis Motor speech disorder TERM 33
Locked In Syndrome
DEFINITION 33 Bilateral pons lesion Interrupts all the descending corticospinal fibers Quadriplegia Loss of all motor speech functions Patient remains fully awake and can only blink TBI *Brain is fine, but body is locked in. TERM 34
Wallenberg
DEFINITION 34 Lateral medulla lesion Loss of pain sensation from the ipsilateral face and contralateral side of the body Limited motor and speech movements of the pharynx, larynx, and soft palate TERM 35
Dejerine
DEFINITION 35 Medial Medulla Lesion Contralateral hemiplegia, contralateral loss of proprioception and vibration Ipsilateral lingual paralysis
Which Cranial Nerves are only sensory?
- I. Olfactory2) II. Optic3) VIII. Acoustic TERM 37
Which Cranial Nerves are only
motor?
DEFINITION 37
- III. Oculomotor2) IV. Trochlear3) VI. Abducens 4) XI. Accessory5) XII. Hypoglossal TERM 38
Which Cranial Nerves are mixed?
DEFINITION 38
- V. Trigeminal2) VII. Facial3) IX. Glossopharyngeal 4) X. Vagus - 90% sensory, 10% motor TERM 39
*What happens if there is damage to Cranial
Nerve VII at the pons?
DEFINITION 39 *All three functions of the facial nerve will likely be affected. Paralysis of the ipsilateral facial muscles Excessive gland secretions Loss of taste from the anterior two thirds of the tongue TERM 40
What happens if there is damage to Cranial
Nerve VII at the motor root?
DEFINITION 40 Excessive gland secretions loss of taste from the anterior two thirds of the tongue
