Nervous System Content Flashcards
What is the name of CN 1, what does it control, and how do you test its function?
- Name: Olfactory
- Controls: Sense of smell
- Test by: Test sense of smell by holding a scent up to nose
What is the name of CN 2, what does it control, and how do you test its function?
- Name: Optic nerve
- Controls: Visual acuity, visual fields, and ocular fundi
- Test by: Use a snellen chart to test visual acuity, test visual field by confrontation (static finger wiggle test)
What is the name of CN 3, what does it control, and how do you test its function?
- Name: Ocularmotor
- Controls: Pupil size and reactivity, eyelid elevation, and extraocular movements
- Test by: Check pupillary reaction
What is the name of CN 4, what does it control, and how do you test its function?
- Name: Trochlear
- Controls: Extraocular movements (Moves eyes downward and laterally)
- Test by: 6 Cardinal directions of gaze and check convergence of the eyes.
What is the name of CN 5, what does it control, and how do you test its function?
- Name: Trigeminal
- Controls: Corneal reflex, facial sensation, mouth motor function
- Test by: Asking pt. to clench teeth, test for facial sensation in 6 points, and check corneal reflex
What is the name of CN 6, what does it control, and how do you test its function?
- Name: Abducens
- Controls: Extraocular movements (turns eye laterally)
- Test by: Having patient move eyes from side to side
What is the name of CN 7, what does it control, and how do you test its function?
- Name: Facial
- Controls: Facial expression, taste, corneal reflex, and lip closure
- Test by: Looking for facial droop/asymmetry. Ask. pt. to smile, frown, and show teeth.
What is the name of CN 8, what does it control, and how do you test its function?
- Name: Vestibulocochlear
- Controls: Ability to hear
- Test by: whisper into the patient’s ear and ask them to repeat what was heard
What is the name of CN 9, what does it control, and how do you test its function?
- Name: Glossopharyngeal
- Controls: Gagging and swallowing (sensation)
- Test by: Having pt. swallow, have pt. say “AH”, test gag reflex
What is the name of CN 11, what does it control, and how do you test its function?
- Name: Accessory
- Controls: Shoulder movement and head rotation
- Test by: Ask pt to move their head from side to side against your hand, have patient shrug shoulders
What is the name of CN 10, what does it control, and how do you test its function?
- Name: Vagus
- Controls: Gagging and swallowing (motor), speech
- Test by: Having pt. swallow, have pt. say “AH”, test gag reflex
What is the name of CN 12, what does it control, and how do you test its function?
- Name: Hypoglossal
- Controls: Tounge movement & speech articulation
- Test by: Have pt. stick out tongue and move it internally from cheek to cheek. Look for asymmetry, atrophy, or deviation of the tongue
How do you conduct the Romberg test?
- This tests a patient’s position sense.
- The patient should first stand with feet together and eyes open and then close both eyes for 30 to 60 seconds without support.
- Note the patient’s ability to maintain an upright posture. Normally any swaying is minimal.
- If the patient stands fairly well with eyes open but loses balance when they are closed, it is a positive Romberg sign
What conditions can cause a positive Romberg test?
- If the patient loses balance while standing with eyes opens this suggests cerebellar ataxia
- If the patient loses balance while standing with eyes closed this suggests impaired proprioception (dorsal column disease)
How do you conduct the pronator drift test?
- The patient should stand for 20 to 30 seconds with eyes closed and both arms held straightforward with palms up.
- Instruct the patient to keep the arms out and eyes shut and tap the arms briskly downward. The arms normally return smoothly to the horizontal position.
- Pronator drift occurs when one forearm and palm turn inward and down
How do you test for the plantar response?
- With a key or the wooden end of an applicator stick, stroke the lateral aspect of the sole from the heel to the ball of the foot, curving medially across the ball (Fig. 17-60).
- Use the lightest stimulus needed to provoke a response, but increase firmness if necessary.
- Closely observe movement of the big toe, normally plantar flexion.
What is a positive Babinski response?
- Occurs when testing the plantar response and dorsiflexion of the big toe occurs
- It is caused by a CNS lesion affecting the corticospinal
tract (sensitivity ∼50%; specificity
99%) - This response can be transiently positive in unconscious states from drug or alcohol intoxication and during the postictal period following a seizure.
What is Brudzinski’s sign and what does it indicate?
- When lying flat ask the patient to flex their neck, watch the hips and knees in reaction to your maneuver. Normally they should remain relaxed and motionless.
- A positive Brudzinski’s sign occurs when there is flexion of both the hips and knees in reaction to flexing the neck
- If positive this indicates there is inflammation in the subarachnoid space causes resistance to movement
that stretches the femoral nerve.
What is Kering’s sign and what does it indicate?
- Flex the patient’s leg at both the hip and the knee, and then slowly extend the leg and straighten the knee. Discomfort behind the knee during full extension is normal but should not produce pain.
- Pain and increased resistance to knee extension are a positive Kernig sign.
- If positive it indicates irritation or compression of a lumbar or sacral nerve root or the sciatic nerve causes radicular or sciatic pain radiating into the leg when the nerve is stretched by extending the leg.
How do you test vibration sense?
- Place a toning fork on the interphalangeal joint of the big toe
- Ask the patient to tell you when the vibration stops
- Confirm with patient
Vibration sense is often the first sensation lost in a peripheral neuropathy and increases the likelihood of peripheral neuropathy
How do you test for proprioception?
- Grasp the patient’s big toe, holding it by its sides between your thumb and index finger, then pull it away from the other toes (Fig. 17-38).
- This prevents extraneous tactile stimuli from affecting testing.
- Demonstrate “up” and “down” as you move the patient’s toe clearly upward and downward.
- Then, with the patient’s eyes closed, ask the patient to say “up” or “down” when moving the large toe in a small arc.
How do you test for ankle clonus?
- If the reflexes seem hyperactive, test for ankle clonus.
- Support the knee in a partly flexed position. With your other hand, dorsiflex and plantar flex the foot a few times while encouraging the patient to relax, then sharply dorsiflex the foot and maintain it in dorsiflexion (Fig. 17-58).
- Look and feel for rhythmic oscillations between dorsiflexion and plantar flexion. Normally the ankle does not react to this stimulus.
How do you test for the oculocephalic reflex?
- Hold the patient’s eyelids open and turn the head quickly, first to one side and then to the other.
- In a normal patient with an intact brainstem, as the head is turned in one direction, the eyes move toward the opposite side.
- If you turn a patient’s head to the right, their eyes should move to the left.
