Neurological Exam

Question 1

How many cranial nerves are there?

Answer 1

12

Question 2

What is cranial nerve 1?

Answer 2

Olfactory.

Unilateral olfactory loss is actually more common than bilateral and occurs with subfrontal masses.

Question 3

What is cranial nerve 2?

Answer 3

Optic nerve.
Optic nerve projects to the lateral geniculate nucleus (LGN) and superior colliculus.

Loss of a visual HEMIFIELD on the same side in both eyes (homonymous hemianopsia) suggests a lesion involving the LGN, optic radiations, or contralateral occipital lobe. This would look like missing half of the field on left (or right) side in each eye.

Loss of a visual field QUADRANT (superior homonymous quadrantanopsia) would suggest involvement of axons in Meyer’s loop in the posterior temporal lobe opposite the field deficit. This is called pie in the sky disorder, the upper top left quadrant might be missing in each eye.

Loss of the visual temporal FIELDS (bitemporal hemianopsia) suggests a chiasmatic lesion (e.g., pituitary adenoma). This would look like missing the left half of vision on the left eye, and missing the right half of vision on the right eye, likely limiting peripheral vision significantly.

Question 4

What is cranial nerve 3?

Answer 4

Oculomotor.
The oculomotor nerve projects from the midbrain to the iris and five of the extraocular muscles (EOMs). A lesion to this nerve may lead to fixed, dilated pupil (blown pupil). CN III controls movement of eyes downward, upward, and or mesial directions

Question 5

What is cranial nerve 4?

Answer 5

Trochlear.

Also controls eye movements. May lead to diplopia if compressed.

Question 6

What is cranial nerve 5?

Answer 6

Trigeminal.
Projects from the pons. Has 3 different divisions - ophthalmic, maxillary, and mandibular. Motor functioning of the trigeminal nerve may be evaluated by asking the patient to open his or her mouth. The jaw will deviate to the side of weakened muscle innervation.

Question 7

What is cranial nerve 6?

Answer 7

Abducens.

Also controls eye movements. May lead to diplopia if compressed.

Question 8

What is cranial nerve 7?

Answer 8

Facial.
Controls motor functions of the upper and lower face, as well as the salivary glands, tear glands, and nasal mucosa.
Assessed by asking patient to smile and watching for unequal elevation of mouth’s corners. Person with facial nerve damage will also be unable to close both eyes or wrinkle their brows symmetrically.

Question 9

What is cranial nerve 8?

Answer 9

Vestibulocochlear.

Auditory and vestibular functions

Question 10

What is cranial nerve 9?

Answer 10

Glossopharyngeal.

Damage to this nerve can result in loss of taste sensation in part of the tongue and impaired swallowing

Question 11

What is cranial nerve 10?

Answer 11

Vagus.

Question 12

What is cranial nerve 11?

Answer 12

Spinal accessory.

Tested by having the patient shrug his or her shoulders. Asymmetric shrug suggests dysfunction o the side that is lower.

Question 13

What is cranial nerve 12?

Answer 13

Hypoglossal.

Tested by tongue protrusion. Tongue deviates toward the side of nerve weakness. Subtle dysarthria may be noted.

Question 14

What is antalgic gait?

Answer 14

When less weight appears placed on one leg, suggesting a pain-guarding strategy.

Question 15

When there is wide-based gait, what could that suggest?

Answer 15

Cerebellar ataxia.

Question 16

If one leg is observed to swing around (circumduct) in an arc, this might suggest what…

Answer 16

Hemiparetic gait.

Question 17

If the lower extremities have reduced knee flexion, and gait has a “scissoring” quality (imagine one blade on surface with next blade on surface), person might walk on tiptoes, this could suggest…

Answer 17

Corticospinal dysfunction.

Question 18

Inability to do tandem gait suggests…

Answer 18

Cerebellar dysfunction or other higher motor dysfunction

Question 19

Dysmetria is?

Answer 19

When there is inaccuracy with upper extremeties in pointing from nose to doctor’s fingertip.

Question 20

What is the Romberg sign?

Answer 20

When unsteadiness occurs while standing with feet together and eyes closed. May suggest loss of propioception.

Question 21

What is sensory extinction?

Answer 21

Extinction to simultaneous sensory stimulation (ESS) is a clinical phenomenon in which a patient perceives a unilateral sensory stimulus presented in isolation but fails to perceive the same stimulus when presented simultaneously with a second stimulus. ESS is most commonly seen after right hemisphere strokes and may adversely affect prognosis. The mechanisms of ESS have not been fully elucidated. The delayed information processing model proposes that delays in the transfer of sensory information in the damaged hemisphere increase the susceptibility to interference from the intact hemisphere.

May suggest contralateral parietal lobe dysfunction

Question 22

What is the use of computed tomography (CT)?

Answer 22

Helps distinguish structures of very different tissue composition (blood vs brain vs bone). Useful in demonstrating hemorrhage, skull fracture, and mass effect. Less useful in primarily white matter conditions or in making refined differential diagnoses (tumor vs other mass).

Question 23

What is use of MRI?

Answer 23

Detects reaction of water molecules within a strong magnetic field after the introduction of a radiowave signal. T1 scans demonstrate greater anatomic detail but less tissue contrast, where as T2 scans have enhanced contrast that has greater clinical benefit in differentiating various types of brain tissue and various neuropathologies. In T2, intact white matter appears gray, but plaques (MS) will appear brighter. CSF also looks brighter on T2 scans, facilitating the identification of cavitated lesions (lacunar infarcts). FLAIR allows for the representation of even greater contrast between normal and pathological tissue.