Cranial Nerve Examination Flashcards
What is the sensory function and disorders of Cranial Nerve I (Olfactory)?
- Smell
- Anosmia (inability to detect smells)
What is the sensory function of Cranial Nerve II (Optic)?
Vision
Lesion in Optic Chiasm results in = ?
(2) Bitemporal hemianopsia:
- Loss of vision in the outer (temporal) half of both visual fields
How is the visual acuity of Cranial Nerve II tested?
Using Snellen’s chart for visual acuity
How is the visual field of Cranial Nerve II tested?
- One eye covered, patient looks into examiner’s eye while finger is moved into visual field.
- Normal = Patient reports seeing the finger
- Abnormal Response = patient cannot see the finger
What is the consensual reflex related to Cranial Nerve II?
Consensual Reflex
- Pupil of one eye constricts when light is shined into the other eye
What motor functions does Cranial Nerve III (Oculomotor) control?
Moves eyes up, down, medially; raises upper eyelid; constricts pupil
What is ptosis?
Drooping of the upper eyelid
How is the smooth pursuit of Cranial Nerve III tested?
- Patient’s eyes follow examiner’s finger moving up, down, and in
- Normal Response: eyes move symmetrically, smoothly
- Abnormal Response: deficits in adduction, depression or elevation of the eye
What is the pupillary light reflex for Cranial Nerve III?
- Shine light into eye; observe constriction of the pupil
- Normal Response: constriction of pupils
- Abnormal Response: response is slow or absent
What is the motor function of Cranial Nerve IV (Trochlear) and how is it tested?
- Moves eye medially and down
- Patient’s eye follows examiner finger about 50 degrees adduction then down
What are the branches of Cranial Nerve V (Trigeminal)?
- Ophthalmic
- Maxillary
- Mandibular
What sensory functions does Cranial Nerve V provide and how are they tested?
- Facial sensation, sensation from TMJ
- Use light touch and pin to assess sensation in 3 areas: forehead, cheek, chin
What is the corneal reflex associated with Cranial Nerve V?
Touch outer cornea with a wisp of cotton; normal response is eye blinks
What is the motor function of Cranial Nerve VI (Abducens)?
Abducts eye
How is Cranial Nerve VI tested?
Patient follows examiner’s finger to look laterally
What motor functions does Cranial Nerve VII (Facial) control?
Facial expression, closes eyes
What is Bell’s Palsy?
Paralysis or paresis of ipsilateral facial muscles
How is Cranial Nerve VII tested?
Facial movements: smile, puff cheeks, close eyes, wrinkle forehead
What is the sensory function of Cranial Nerve VIII (Vestibulocochlear)?
Hearing and balance
What is the Rinne test?
Hold vibrating tuning fork on mastoid bone, then move it near the ear
What is the Weber test?
Hold vibrating tuning fork on top of the head; ask where sound is heard
What is sensorineural deafness?
Damage to receptor cells or cochlear nerve, less common than conductive deafness
What motor function does Cranial Nerve IX (Glossopharyngeal) control?
Swallowing
How is the gag reflex tested?
Touch soft palate with cotton swab; normal response is gagging
What are the motor functions of Cranial Nerve X (Vagus)?
Regulates viscera, swallowing, speech
What is the normal response for the soft palate test of Cranial Nerve X?
Elevation of soft palate when patient says ‘ah’
What is the motor function of Cranial Nerve XI (Spinal Accessory)?
Elevates shoulders, turns head
How is Cranial Nerve XI tested?
Manual muscle test of SCM and trapezius
What motor function does Cranial Nerve XII (Hypoglossal) control?
Moves tongue
How is Cranial Nerve XII tested?
Protrude tongue; normal response is midline protrusion
What is the pupillary reflex?
Pupil constricts when light is shined into the eye
What nerves are involved in the corneal reflex?
- Afferent: Trigeminal (CN V)
- Efferent: Facial (CN VII)
What is the accommodation reflex?
Lens adjusts to focus light on retina; pupils move medially for close objects
What is the masseter reflex?
Masseter muscle contracts when tapped with a reflex hammer
How is visual acuity tested?
Using Snellen’s chart at a specified distance
What is diplopia?
Double vision
What is homonymous hemianopia?
Inability to see half of the visual field in each eye
What is the normal response for the consensual reflex?
Pupil constricts in response to light shined in the other eye
What is the normal response for the convergence test?
Both eyes move toward the pen tip until it is within 6 cm of the nose
What does Cranial Nerve IX affect?
Taste and salivation
What are the disorders associated with Cranial Nerve X?
- Difficulty speaking & swallowing
- Poor digestion
- Cardiac dysrhythmia
How is Cranial Nerve III tested for pupillary light reflex?
Shine light into eye; observe pupil constriction
What does Cranial Nerve XI innervate?
SCM and trapezius muscles
What is the sensory function of Cranial Nerve II?
Vision
How is the pupillary light reflex tested?
Shine light into eye; observe pupil of the other eye (consensual reflex)
What is the role of the Vestibulocochlear nerve?
Hearing and balance
How is conductive deafness tested?
Rinne and Weber tests
What is the function of the Glossopharyngeal nerve?
Taste and salivation
