A 45-year-old man has sudden right-sided facial weakness: he cannot wrinkle the right forehead or close the right eye. He has lost taste on the anterior two-thirds of the right side of the tongue and finds loud sounds painful in the right ear. Schirmer test shows normal tear secretion on both sides. Where is the lesion in the facial nerve?

Between the geniculate ganglion and the nerve to stapedius

Proximal to the geniculate ganglion

Between the nerve to stapedius and the chorda tympani

A 70-year-old man is admitted with sudden weakness of his right arm and leg. The lower part of his right face droops and he cannot show his teeth on that side, but he can wrinkle his forehead and close both eyes tightly. What best explains the sparing of the upper face?

The upper face motor neurons receive input from both hemispheres

The upper face motor neurons receive only crossed fibres

The temporal branch leaves the facial nerve before the lesion

The upper face is supplied by the trigeminal nerve

Cranial nerves and their lesions

20 NEET-PG practice questions on Cranial nerves and their lesions, part of Anatomy. The first 20 are below; the first 5 with answers and explanations (tap Show answer after you have chosen), the rest in Learn with a free account.

Question 1 · Medium
A 45-year-old man has sudden right-sided facial weakness: he cannot wrinkle the right forehead or close the right eye. He has lost taste on the anterior two-thirds of the right side of the tongue and finds loud sounds painful in the right ear. Schirmer test shows normal tear secretion on both sides. Where is the lesion in the facial nerve?
1. ABetween the geniculate ganglion and the nerve to stapedius
2. BAt the stylomastoid foramen
3. CProximal to the geniculate ganglion
4. DBetween the nerve to stapedius and the chorda tympani
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Answer: A · Between the geniculate ganglion and the nerve to stapedius
Forehead involvement makes this a lower motor neuron facial palsy, and the branches lost or kept locate the lesion. Normal tears mean the greater petrosal nerve, which leaves at the geniculate ganglion, is spared, so the lesion is distal to the ganglion. Hyperacusis means the nerve to stapedius is lost, and loss of taste means the chorda tympani is lost, so the lesion is above both, in the vertical segment just after the ganglion. Topodiagnostic tests such as these help predict recovery and plan decompression.
- B: A lesion at the stylomastoid foramen spares taste and hearing.
- C: A lesion proximal to the ganglion would also reduce tear secretion.
- D: A lesion below the nerve to stapedius would spare the stapedius and cause no hyperacusis.
Question 2 · Medium
A 3-day-old baby was delivered by assisted breech delivery with traction on the arms. His right hand is limp and clawed, while the shoulder and elbow move normally. The right pupil is smaller than the left and the right upper eyelid droops slightly. Involvement of which structure explains the eye signs?
1. ACiliary ganglion
2. BSuperior cervical ganglion
3. CFirst thoracic ventral root
4. DOculomotor nerve
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Answer: C · First thoracic ventral root
A limp, clawed hand with a normal shoulder and elbow is a lower plexus (C8-T1, Klumpke) injury. The preganglionic sympathetic fibres for the head leave the spinal cord through the first thoracic ventral root and its white ramus, so avulsion of T1 close to the cord cuts them and causes Horner syndrome. Horner syndrome with a birth plexus injury therefore suggests root avulsion, which has a poorer chance of spontaneous recovery. Such babies need early referral to a brachial plexus team.
- A: Ciliary ganglion damage gives a large, poorly reacting pupil, not a small one.
- B: The superior cervical ganglion lies high in the neck, away from a lower plexus traction injury.
- D: An oculomotor lesion causes a dilated pupil and severe ptosis.
Question 3 · Medium
A 58-year-old woman on chemotherapy for breast cancer has had severe pain in the left ear for 3 days, followed by vesicles in the external auditory canal and on the concha. She now has weakness of the whole left half of her face, including the forehead, with ringing in the ear and vertigo. In which ganglion has the virus reactivated?
1. ASpiral ganglion
2. BPterygopalatine ganglion
3. CTrigeminal ganglion
4. DGeniculate ganglion
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Answer: D · Geniculate ganglion
Ear pain, vesicles in the canal and concha and a lower motor neurone facial palsy make up Ramsay Hunt syndrome, reactivation of varicella-zoster virus in the geniculate ganglion. The geniculate ganglion is the sensory ganglion of the facial nerve, at its bend in the facial canal, and supplies sensation to part of the external ear. Spread to the nearby vestibulocochlear nerve causes tinnitus, hearing loss and vertigo. Antivirals with steroids are started early; recovery is less complete than in Bell palsy.
- A: The spiral ganglion is the cochlear ganglion and has no link to facial weakness.
- B: The pterygopalatine ganglion is a parasympathetic ganglion for lacrimal and nasal glands.
- C: Trigeminal ganglion zoster causes ophthalmic or facial zoster, without a facial palsy.
Question 4 · Medium
A 39-year-old man has a complete right oculomotor nerve palsy from a compressive lesion. The resident lists four findings he expects in the right eye: 1. Complete ptosis. 2. Eye turned down and out in primary gaze. 3. Constricted pupil. 4. Loss of accommodation for near vision. Which findings are expected?
1. A1, 2 and 4 only
2. B1, 3 and 4 only
3. C2 and 4 only
4. D1, 2, 3 and 4
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Answer: A · 1, 2 and 4 only
Statements 1, 2 and 4 are correct. The oculomotor nerve supplies levator palpebrae superioris (so ptosis is complete), and four of the six extraocular muscles; the unopposed lateral rectus and superior oblique hold the eye down and out. Its parasympathetic fibres relay in the ciliary ganglion to the sphincter pupillae and ciliary muscle, so a complete lesion causes a dilated, not a constricted, pupil and loss of accommodation. A small pupil with mild ptosis would suggest Horner syndrome instead.
- B: Includes a constricted pupil and omits the down-and-out eye.
- C: Omits complete ptosis from paralysis of levator palpebrae superioris.
- D: Includes a constricted pupil; the pupil is dilated in a complete third nerve palsy.
Question 5 · Medium
A 70-year-old man is admitted with sudden weakness of his right arm and leg. The lower part of his right face droops and he cannot show his teeth on that side, but he can wrinkle his forehead and close both eyes tightly. What best explains the sparing of the upper face?
1. AThe upper face motor neurons receive only crossed fibres
2. BThe temporal branch leaves the facial nerve before the lesion
3. CThe upper face motor neurons receive input from both hemispheres
4. DThe upper face is supplied by the trigeminal nerve
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Answer: C · The upper face motor neurons receive input from both hemispheres
This is an upper motor neurone facial palsy from a lesion of the left corticobulbar fibres, for example in the internal capsule. The part of the facial nucleus that supplies the forehead and orbicularis oculi receives corticobulbar fibres from both hemispheres, so one intact hemisphere keeps the upper face working. The part for the lower face receives mainly crossed fibres and is weakened. A lower motor neurone lesion of the nucleus or nerve paralyses the whole half of the face.
- A: Only-crossed input would make the forehead weak, which is the pattern for the lower face.
- B: The temporal branch arises in the parotid, far beyond any lesion that causes hemiplegia.
- D: The trigeminal nerve is sensory to the face and motor only to the muscles of mastication.
Question 6 · Easy
Which brainstem nucleus gives motor fibres to the muscles of the soft palate, pharynx and larynx?
1. ANucleus of the tractus solitarius
2. BDorsal motor nucleus of the vagus
3. CInferior salivatory nucleus
4. DNucleus ambiguus
Answer and explanation in LearnFree account
Question 7 · Hard
A 12-year-old boy from a village in Rajasthan has had a foul-smelling discharge from his right ear for many months. For a week he has had deep pain behind the right eye and double vision on looking to the right; the right eye does not abduct. He is alert, and both fundi are normal. What is the most likely diagnosis?
1. ALateral sinus thrombosis
2. BOtitic hydrocephalus
3. CPetrous apicitis
4. DCavernous sinus thrombosis
Answer and explanation in LearnFree account
Question 8 · Easy
A 61-year-old man who has smoked bidis for 40 years has had aching pain along the inner side of his right arm and forearm for 3 months. His right upper eyelid droops by about 2 mm, the right pupil is smaller than the left, and the right side of his face stays dry when he sweats. Chest X-ray shows a right apical opacity. Paralysis of which muscle causes the drooping eyelid?
1. ALevator palpebrae superioris
2. BOrbicularis oculi
3. CSuperior tarsal muscle
4. DFrontalis
Answer and explanation in LearnFree account
Question 9 · Medium
A 48-year-old hypertensive woman is brought to casualty with a severe headache that began suddenly an hour ago. Her right upper eyelid has dropped completely. When the lid is lifted, the right eye is turned down and out, and the right pupil is 7 mm and does not react to light. What is the most likely cause?
1. APosterior communicating artery aneurysm
2. BDiabetic microvascular nerve infarct
3. CRight cavernous sinus thrombosis
4. DRight paramedian midbrain infarct
Answer and explanation in LearnFree account
Question 10 · Medium
A 64-year-old man with diabetes for 15 years wakes with double vision and an ache around the left eye. The left eyelid droops and the left eye is turned down and out, but both pupils are equal and react normally to light. Why is the pupil spared?
1. APupillary fibres run in the core of the nerve
2. BPupillary fibres join the nerve within the orbit
3. CPupillary fibres travel with the abducens nerve
4. DPupillary fibres lie superficially, outside the infarct
Answer and explanation in LearnFree account
Question 11 · Medium
A 46-year-old woman has a slowly growing tumour at the right cerebellopontine angle. When a wisp of cotton touches her right cornea, neither eye blinks. When it touches her left cornea, both eyes blink briskly. Which nerve is affected?
1. ALeft ophthalmic nerve
2. BRight facial nerve
3. CLeft facial nerve
4. DRight ophthalmic nerve
Answer and explanation in LearnFree account
Question 12 · Hard
A 29-year-old woman with relapsing episodes of neurological symptoms has a new demyelinating plaque on MRI in the floor of the fourth ventricle on the right. The whole right half of her face is weak, including the forehead. Neither eye can look to the right, although each eye moves fully to the left and convergence is normal. Which structure, besides the facial nerve fibres, is damaged?
1. ALeft frontal eye field
2. BRight medial longitudinal fasciculus
3. CRight abducens nucleus
4. DRight abducens nerve
Answer and explanation in LearnFree account
Question 13 · Medium
A 24-year-old motorcyclist recovers from a closed head injury but now has vertical double vision that is worse when he reads or walks down stairs. He keeps his head tilted towards his left shoulder. On cover testing the right eye sits higher, and the deviation increases when he looks to the left and down. Which nerve is damaged?
1. ARight trochlear nerve
2. BRight abducens nerve
3. CRight oculomotor nerve
4. DLeft trochlear nerve
Answer and explanation in LearnFree account
Question 14 · Medium
A 50-year-old man from Nagaland with nasopharyngeal carcinoma has had a nasal voice for a month, and fluids come back through his nose when he drinks. When he says 'aah', the uvula is pulled to the right and the left side of the palate does not rise. Which nerve is affected?
1. ALeft glossopharyngeal nerve
2. BLeft vagus nerve
3. CRight vagus nerve
4. DLeft hypoglossal nerve
Answer and explanation in LearnFree account
Question 15 · Medium
A 67-year-old man with atrial fibrillation who stopped his anticoagulant a month ago suddenly develops weakness of the left arm and leg with an extensor left plantar. His right eyelid droops completely, and the right eye is turned down and out with a dilated pupil. Where is the lesion?
1. ARight half of the pons
2. BRight half of the midbrain
3. CLeft half of the midbrain
4. DRight internal capsule
Answer and explanation in LearnFree account
Question 16 · Medium
A 52-year-old man has had numbness of the right lower lip, chin and lower teeth for 2 months. The right temporal fossa looks hollow, and when he opens his mouth wide, the jaw deviates to the right. MRI shows a tumour at the right side of the skull base. Weakness of which muscle causes the jaw to deviate?
1. ARight lateral pterygoid
2. BRight masseter
3. CRight medial pterygoid
4. DLeft lateral pterygoid
Answer and explanation in LearnFree account
Question 17 · Easy
Two days after a left carotid endarterectomy, a 66-year-old man finds that his speech is slurred and food collects in his left cheek. When he puts out his tongue, it deviates to the left, and the left half of the tongue looks wrinkled. Which nerve was most likely injured?
1. ARight hypoglossal nerve
2. BLeft glossopharyngeal nerve
3. CLeft hypoglossal nerve
4. DLeft lingual nerve
Answer and explanation in LearnFree account
Question 18 · Hard
A 38-year-old man has had pain on the left side of his neck and face for 2 days, starting after a vigorous neck manipulation by a roadside barber. His left upper eyelid droops by 2 mm and his left pupil is smaller, more obvious in dim light. Sweating of the face is normal and equal on both sides. Where along the sympathetic pathway does this pattern place the lesion?
1. AIn the first thoracic ventral root
2. BAlong the wall of the internal carotid artery
3. CIn the lateral medulla of the brainstem
4. DAt the apex of the lung
Answer and explanation in LearnFree account
Question 19 · Hard
A 34-year-old man has had weakness of the whole right side of his face since an injury to the side of his head. He cannot wrinkle the right forehead or close the right eye. Schirmer test shows equal tear production in both eyes, taste on the anterior two-thirds of the tongue is normal on both sides, and the right stapedial reflex is present. Where is the facial nerve most likely damaged?
1. AAt the stylomastoid foramen
2. BBetween the nerve to stapedius and the chorda tympani
3. CAt the geniculate ganglion
4. DIn the internal acoustic meatus
Answer and explanation in LearnFree account
Question 20 · Easy
A 26-year-old obese woman visits the eye OPD with headache for 2 months and horizontal double vision that is worse when she looks at distant objects. Both optic discs are swollen. MRI brain is normal, and lumbar puncture shows an opening pressure of 34 cm H2O with normal CSF. Her right eye cannot move outward beyond the midline. Which nerve is affected?
1. AAbducens nerve
2. BTrochlear nerve
3. COculomotor nerve
4. DFacial nerve
Answer and explanation in LearnFree account

Cranial nerves and their lesions

A 70-year-old man is admitted with sudden weakness of his right arm and leg. The lower part of his right face droops and he cannot show his teeth on that side, but he can wrinkle his forehead and close both eyes tightly. What best explains the sparing of the upper face?

Which brainstem nucleus gives motor fibres to the muscles of the soft palate, pharynx and larynx?

A 64-year-old man with diabetes for 15 years wakes with double vision and an ache around the left eye. The left eyelid droops and the left eye is turned down and out, but both pupils are equal and react normally to light. Why is the pupil spared?

A 46-year-old woman has a slowly growing tumour at the right cerebellopontine angle. When a wisp of cotton touches her right cornea, neither eye blinks. When it touches her left cornea, both eyes blink briskly. Which nerve is affected?

A 50-year-old man from Nagaland with nasopharyngeal carcinoma has had a nasal voice for a month, and fluids come back through his nose when he drinks. When he says 'aah', the uvula is pulled to the right and the left side of the palate does not rise. Which nerve is affected?

A 67-year-old man with atrial fibrillation who stopped his anticoagulant a month ago suddenly develops weakness of the left arm and leg with an extensor left plantar. His right eyelid droops completely, and the right eye is turned down and out with a dilated pupil. Where is the lesion?

Two days after a left carotid endarterectomy, a 66-year-old man finds that his speech is slurred and food collects in his left cheek. When he puts out his tongue, it deviates to the left, and the left half of the tongue looks wrinkled. Which nerve was most likely injured?