Tag: Optic nerve

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53. Exits of cranial nerves from the skull

  1. Cribriform plate: Olfactory nerve. (T/F?)
  2. Optic foramen: Optic nerve. (T/F?)
  3. Superior orbital fissure: Ophtalmic nerve. (T/F?)
  4. Foramen ovale: Maxillary nerve. (T/F?)
  5. Foramen rotundum: Mandibullary nerve. (T/F?)
  6. Jugular foramen: Vagus nerve. (T/F?)

  1. T
  2. T
  3. T
  4. F
  5. F
  6. T

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7. Internuclear ophthalmoplegia:

  1. Results in double vision, due to lesion of the medial longitudinal fasciculus (MLF), which connects the nuclei of oculomotor and abducens nerves. (T/F?)
  2. Is always  unilateral. (T/F?)
  3. Diplopia  is elicited with the gaze to the opposite side of  the affected eye. (T/F?)
  4. Affected eye shows impairment ( slower rate or failure ) of adduction. (T/F?)
  5. Contralateral (not  affected) eye shows vertical nystagmus  with abduction. (T/F?)
  6. If the left eye is affected, the patient will have diplopia when looking to the left. (T/F?)
  7. With rostral MLF lesions, near the oculomotor  nucleus, convergence of  the eyes may be impaired. (T/F?)

  1. T
  2. F
  3. T
  4. T
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  6. F
  7. T

Henry Vandyke Carter [Public domain], via Wikimedia Commons

  1. Internuclear ophthalmoplegia is also called medial longitudinal fasciculus syndrome  or MLF syndrome.
  2. MLF syndrome can occur unilaterally or bilaterally. Bilateral internuclear ophthalmoplegia is highly suspected for multiple sclerosis, specially with young people.
  1. Contralateral eye characteristically shows horizontal nystagmus with abduction.
  2. If the left eye is affected, the patient will show horizontal diplopia with gaze to the opposite, right side.

Video: https://www.youtube.com/watch?v=MWJz75R01s4

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6. Signs and symptoms of optic neuritis

  1. Reduced visual acuity. (T/F?)
  2. Dulling of color vision in the affected eye. (T/F?)
  3. Pain around the eye that is not affected by eye movement or touching the eye. (T/F?)
  4. Transient worsening of vision with decrease of body temperature. (T/F?)
  5. Ophthalmoscopy findings are frequently normal. (T/F?)
  6. Are frequent initial symptoms of multiple sclerosis. (T/F)

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  2. T
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  4. F
  5. T
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  1. Optic neuritis is a demyelinating inflammation of the optic nerve. Transient worsening of vision with increase of body temperature is typically observed in this condition.
  2. Pain is typically provoked and intensified by eye movement and touching of the eye.

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3. Optic nerve

  1. Is also known as the second cranial nerve. (T/F?)
  2. Is wrapped around with Schwann cells. (T/F?)
  3. Is covered with all three meningeal layers. (T/F?)
  4. Leaves the orbit through superior orbital fissure. (T/F?)
  5. Is not affected with Guillain–Barré syndrome. (T/F?)
  6. Some of its axons terminate in the pretectal nuclei. (T/F?)

  1. T
  2. F
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  6. T

  1. The first is the olfactory nerve.
  2. The optic nerve is, actually, a part of the central nervous system because it is developed from the outgrowth of the diencephalon (optic vesicle, optic stalk). It is composed of retinal ganglion cells and glial cells and is covered by myelin produced by oligodendrocytes.
  3. They follow the nerve as it grows from the diencephalon.

    Henry Vandyke Carter [Public domain], via Wikimedia Commons
  4. It goes through the optic foramen and continues through the optic canal.
    Henry Vandyke Carter [Public domain], via Wikimedia Commons
  5. Hmm… GBS is primarily a peripheral demyelinating disease and it should not affect the optic nerve or any other part of CNS, but…
  6. Pretectal nuclei mediate functions like pupillary light reflex, optokinetic reflex and some others.