Cranial Nerves MCQs

Anatomy · 71 free questions with answers & explanations.

1. A patient with a posterior communicating artery aneurysm develops ptosis, mydriasis, and the eye is directed 'down and out.' Which nerve is compressed, and at which location does the parasympathetic component travel?
2. Which cranial nerve provides taste sensation from the posterior one-third of the tongue?
3. A 30-year-old woman presents with sudden severe facial pain triggered by chewing that follows the distribution of the mandibular division. Which ganglion contains the cell bodies of the primary afferent neurons responsible for this pain?
4. A patient with a lesion of the right abducens nerve nucleus in the pons will exhibit which gaze palsy?
5. The nerve of the pterygoid canal (Vidian nerve) carries which functional fiber components?
6. A patient with a posterior communicating artery aneurysm develops a complete third nerve palsy with a dilated, unreactive pupil. The pupil is affected because the aneurysm compresses which fibres of CN III FIRST?
7. A 45-year-old woman undergoing parotidectomy develops inability to close her eye, loss of the corneal reflex, and deviation of the angle of the mouth to the opposite side. The nerve injury is MOST likely at which segment of the facial nerve?
8. A patient with an acoustic neuroma (vestibular schwannoma) pressing in the cerebellopontine angle develops hoarseness, ipsilateral loss of the gag reflex, and ipsilateral vocal cord palsy. Which cranial nerve is MOST likely affected by direct extension of the tumour?
9. A 32-year-old woman presents with anosmia following a head injury sustained when the back of her head struck the floor. The mechanism of anosmia is BEST explained by:
10. The chorda tympani nerve carries taste from the anterior 2/3 of the tongue and preganglionic parasympathetic fibres to the submandibular ganglion. At which specific anatomical location does chorda tympani join the lingual nerve?
11. A 40-year-old patient is found to have a dilated, unreactive pupil with ptosis and a 'down and out' eye position. CT reveals a posterior communicating artery aneurysm. Why does CN III palsy from a PCA aneurysm characteristically affect the pupil first (pupil-involving palsy)?
12. The nervus intermedius (intermediate nerve) is a component of CN VII. Which functional fibre types does it carry?
13. A patient has absent corneal reflex on the right side but winking (blink response) is present in the right eye when the left cornea is stimulated. Which specific part of the reflex arc is interrupted?
14. A patient with a vestibular schwannoma (acoustic neuroma) at the cerebellopontine angle presents with unilateral sensorineural hearing loss and tinnitus. The nerve most at risk of compression SECOND (after CN VIII) as the tumour enlarges is:
15. The nerve of the pterygoid canal (Vidian nerve) is formed by the union of the greater petrosal nerve and the deep petrosal nerve. The greater petrosal nerve carries fibres from which nucleus?
16. A patient has complete left CN III palsy with a blown pupil and ptosis. On attempted right gaze, the left eye cannot adduct. This reflects damage at which level?
17. The chorda tympani nerve is a branch of which cranial nerve and carries which modality?
18. A 45-year-old presents with left-sided ear pain, vesicles in the external auditory meatus, and ipsilateral lower motor neuron facial palsy. This is Ramsay Hunt syndrome. The ganglion harbouring the dormant varicella-zoster virus that is reactivated is:
19. A patient develops inability to wrinkle the forehead AND inability to close the eye on the left side, with left facial drooping. Upper motor neuron (UMN) or lower motor neuron (LMN) lesion, and at which level?
20. The chorda tympani nerve, a branch of CN VII, carries special visceral afferent (SVA) fibers for taste from which region and travels with which other nerve in the infratemporal fossa?
21. A 70-year-old presents with sudden severe 'thunderclap' headache. On examination, there is bilateral ptosis with pupils fixed and dilated. No meningismus. Which CN is compressed and where?
22. Which ganglion is associated with CN IX (glossopharyngeal nerve), houses cell bodies of visceral afferents from the carotid body and sinus, and is located at the jugular foramen?
23. A 30-year-old patient after parotid surgery develops inability to close the right eye, drooping of the right corner of the mouth, and loss of wrinkling of the right forehead. The lesion is most likely at which level?
24. In a patient with a lesion at the cavernous sinus, which cranial nerve is LEAST likely to be affected because of its location within the sinus?
25. A patient complains of pain behind the ear following herpes zoster reactivation and is found to have ipsilateral facial palsy, vesicles in the external auditory meatus, and tinnitus. What is the anatomical basis of the auricular vesicles in this condition?
26. Which of the following is the correct parasympathetic pathway for lacrimation?
27. A patient presents with unilateral ptosis, mydriasis, and the eye is directed 'down and out.' The pupillary light reflex is absent. MRI shows an aneurysm at the junction of the posterior communicating artery and the internal carotid artery. Which structural feature of CN III makes it susceptible to compressive (surgical) aneurysms?
28. Which ganglion carries postganglionic parasympathetic fibers for secretomotor supply to the parotid gland, and through which cranial nerve does the preganglionic fiber travel to reach this ganglion?
29. A 35-year-old patient after a severe head injury develops anosmia (complete loss of smell). The mechanism is most likely disruption of which anatomical structure?
30. The nerve of the pterygoid canal (Vidian nerve) carries which two functional components and from which two nerves does it originate?
31. A patient has paralysis of all extraocular muscles of the left eye, ptosis, and a fixed dilated left pupil but intact corneal reflex. Additionally, left-sided jaw deviation on opening the mouth is absent. Which cranial nerve is the ONLY one affected?
32. The chorda tympani nerve carries taste from the anterior two-thirds of the tongue and also carries secretomotor fibers to submandibular and sublingual glands. At which ganglion does the secretomotor preganglionic fiber synapse?
33. A 42-year-old patient with a history of chronic otitis media develops sudden onset of unilateral facial palsy, hyperacusis, and loss of taste on the anterior tongue. The lesion is most likely at which segment of the facial nerve canal?
34. A patient presents with ipsilateral tongue deviation, ipsilateral sternocleidomastoid and trapezius weakness, and no sensory loss. At which point in the posterior cranial fossa could a single lesion account for all three findings?
35. The chorda tympani nerve, a branch of CN VII, provides preganglionic parasympathetic fibers to the submandibular and sublingual glands by synapsing in which ganglion?
36. A 32-year-old woman develops sudden right-sided Bell's palsy. She also reports decreased salivation on the right side and altered taste from the anterior right tongue. At which level along the facial nerve course is the lesion most likely located?
37. A patient with a lesion of the right oculomotor nerve (CN III) in the interpeduncular fossa presents with complete ptosis and a fixed dilated pupil. The eye is also deviated outward and downward. Which of the following muscles is SPARED?
38. A 32-year-old woman presents with episodic severe lancinating facial pain triggered by eating, in the territory of the posterior tongue and fauces. This is most consistent with neuralgia of which nerve, and which ganglion contains its cell bodies?
39. The nervus intermedius (nerve of Wrisberg), which joins the facial nerve trunk, carries which combination of fiber types?
40. A patient with a basal skull fracture through the petrous temporal bone develops loss of taste from the anterior two-thirds of the tongue and hyperacusis (hypersensitivity to loud sounds), but facial motor function is intact. Where is the lesion along the facial nerve pathway?
41. The ciliary ganglion, located within the orbit, carries postganglionic parasympathetic fibers. The preganglionic parasympathetic input to the ciliary ganglion is conveyed via which root?
42. A 55-year-old patient with nasopharyngeal carcinoma extending to the skull base develops loss of sensation over the hard palate and soft palate. Which branch of the trigeminal nerve is most likely compressed?
43. The chorda tympani nerve, a branch of CN VII, carries which functional components?
44. In a patient with a complete right CN III palsy, which of the following is MOST indicative of surgical (compressive) rather than medical (ischaemic) aetiology?
45. Which cranial nerve passes through the cavernous sinus embedded within its lateral wall (as opposed to those passing through its lumen)?
46. A patient develops loss of taste from the anterior two-thirds of the tongue on the right, reduced salivation from submandibular and sublingual glands, and hyperacusis on the right, but no facial weakness. Where is the lesion in the facial nerve?
47. Voluntary upward gaze is controlled by the rostral interstitial nucleus of the medial longitudinal fasciculus (riMLF). A unilateral riMLF lesion produces:
48. The trochlear nerve (CN IV) is unique among cranial nerves in that it:
49. A patient has a right third cranial nerve palsy with a dilated, fixed pupil, ptosis, and 'down-and-out' deviation of the right eye. Which finding best distinguishes a compressive (surgical) cause from a microvascular (medical) cause?
50. The chorda tympani nerve carries which functional components, and through which foramen does it exit the skull?
51. The chorda tympani nerve, a branch of CN VII, runs across the tympanic membrane. Which precise course does it take through the middle ear?
52. A patient with an isolated left trochlear nerve (CN IV) palsy displays which eye movement deficit and compensatory head posture?
53. Involvement of which cranial nerve produces the characteristic triad of ipsilateral Horner syndrome, loss of pain and temperature on the face, and dysphagia/hoarseness in a lateral medullary infarct?
54. A patient with a cavernous sinus thrombosis develops complete ophthalmoplegia, Horner syndrome, and loss of all facial sensation. The combination of a fixed dilated pupil alongside Horner syndrome in cavernous sinus pathology is explained by:
55. The nervus intermedius (the sensory and parasympathetic root of CN VII) carries taste from the anterior two-thirds of the tongue via the chorda tympani. The cell bodies of these taste afferents reside in:
56. A patient presents with inability to shrug the right shoulder and weakness turning the head to the left. Which nerve is damaged, and where is the most likely lesion causing BOTH deficits simultaneously?
57. A patient has a lesion of the right trochlear nerve (CN IV). Which clinical finding is most specific for CN IV palsy?
58. The chorda tympani nerve passes through the middle ear crossing the tympanic membrane medially, between the malleus and incus. It exits the skull via which foramen?
59. The nucleus ambiguus provides the motor neurons for which cranial nerves, and its lesion (as in Wallenberg syndrome) produces which specific deficit?
60. The chorda tympani nerve enters the infratemporal fossa through the petrotympanic fissure and joins the lingual nerve. The chorda tympani carries which modalities?
61. A patient develops diplopia on downward gaze and difficulty descending stairs. Examination shows the right eye is slightly higher and extorted. The affected nerve courses around which structure at risk during posterior fossa surgery?
62. The auriculotemporal nerve is a branch of CN V3 that is particularly involved in Frey's syndrome after parotid surgery. It carries which nerve fibers post-operatively that cause gustatory sweating?
63. A patient has diminished lacrimation on the right side and loss of taste from the anterior two-thirds of the right tongue, but has normal facial muscle movement. The lesion is most likely in the:
64. The nerve to stapedius muscle arises from the facial nerve at which point?
65. The abducens nerve (CN VI) is especially vulnerable to raised intracranial pressure producing a 'false localizing sign.' This is because the nerve:
66. The ansa cervicalis (C1–C3) innervates all of the strap muscles EXCEPT which one?
67. A patient undergoing posterior fossa surgery develops nystagmus directed away from the side of the lesion with the fast phase toward the normal side. The Romberg test shows falling toward the same side as the lesion. Cerebellar function tests are normal. This presentation is most consistent with a lesion of:
68. A patient presents with sudden onset painless diplopia on downward gaze — especially when descending stairs — with difficulty reading. The affected muscle is:
69. Testing of the gag reflex involves which two cranial nerves as afferent and efferent limbs respectively?
70. A 45-year-old man develops a unilateral lower motor neuron facial nerve palsy involving the forehead. Where is the lesion most likely located?
71. The chorda tympani nerve joins the lingual nerve in the infratemporal fossa. It is a branch of which cranial nerve, and what does it carry?