Functional Components of the Cranial Nerves - Learning Objectives and Review Questions


  1. The olfactory nerve fascicles pass through the cribriform plate of the ethmoid bone to enter the nasal cavity from the anterior cranial fossa.
  2. A fracture of the cribriform plate may cause a CSF leak.
  3. The olfactory nerve has native SVA and GVE components.
  4. A hypophyseal tumor is expected to disrupt central vision.
  5. The chiasmatic groove is posterior to the hypophyseal fossa.
  6. The afferent limb of the pupillary light reflex is mediated by the SSA component of the oculomotor nerve.
  7. A lesion of the proximal superior division of the oculomotor nerve is expected to disrupt GSE and GVE components.
  8. Preganglionic GVE cell bodies from the Edinger-Westphal nucleus synapse in the submandibular ganglion.
  9. The short ciliary nerves host native GSA fibers non-native preganglionic GVE fibers.
  10. Postganglionic GVE fibers having cell bodies in the ciliary ganglion mediate accommodation as well as pupillary dilation.
  11. A lesion of the greater superficial petrosal nerve at the lacerate foramen disrupts preganglionic GVE fibers that influence lacrimation.
  12. The short ciliary nerves host non-native postganglionic fibers from both divisions of the autonomic nervous system.
  13. A lesion of the internal carotid nerve is expected to disrupt preganglionic sympathetic GVE fibers and cause unilateral mydriasis.
  14. A cavernous sinus infection is expected to cause unilateral pupil dilation given that the sympathetic root of the ciliary ganglion remains healthy.
  15. A mild ptosis in a young person may be caused by a GVE disturbance whereas a frank ptosis is caused by GSE disturbance.
  16. Sneezing while looking at bright light is thought to be, in part, mediated by the GSA component of the trigeminal nerve.
  17. The infraorbital nerve, while in the infraorbital canal, carries non-native postganglionic GVE fibers en route to the lacrimal gland.
  18. The lacrimal nerve proper is GSA only and does not mediate lacrimation.
  19. Traveling along with the distal parts of the lacrimal nerve are postganglonic GVE fibers whose cell bodies are located in the pterygopalatine ganglion.
  20. The extraocular muscles, with the exception of the superior oblique, are innervated by SVE fibers.

Short Answer

  1. lesser superficial petrosal nerve.
  2. Mandibular division of the trigeminal nerve.
  3. Hypophyseal tumors and the optic chiasm.
  4. The "hitchhikers" that follow trigeminal pathways.
  5. Chorda tympani nerve.


  1. There is a lesion of the facial nerve. Propose a series of tests to verify the lesion location. Use your knowledge of functional components to exhaustively validate the lesion location. You chose the lesion location.
  2. Be prepared to answer the above question for each of the cranial nerves.
Topic revision: r3 - 31 Oct 2018, LorenEvey
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