Facial Nerve Disorders — MCQs
In Ramsay Hunt syndrome, the most commonly involved nerve is?
The facial nerve's first branch is?
Herpes zoster in geniculate ganglion causes?
A 40-year-old man presents with sudden onset of unilateral facial paralysis. He is unable to close his eye or raise his eyebrow. What is the most likely diagnosis?
In a case of unilateral supranuclear lesion of the facial nerve, which part of the face is affected?
Most common cause of facial nerve palsy is -
Facial nerve palsy at stylomastoid foramen can cause-
Mark the false statement regarding nucleus of facial nerve :
True about acoustic neuroma:
During acute tonsillitis, referred pain from the tonsil to the middle ear occurs via which nerve?
Facial Nerve Disorders Indian Medical PG Practice Questions and MCQs
Question 1: In Ramsay Hunt syndrome, the most commonly involved nerve is?
- A. a. V
- B. b. VII (Correct Answer)
- C. d. IX
- D. c. VIII
Explanation: ***VII*** - Ramsay Hunt syndrome (herpes zoster oticus) is caused by the reactivation of the **varicella-zoster virus** in the **geniculate ganglion**, which is part of the **facial nerve (cranial nerve VII)** [1]. - This reactivation leads to **unilateral facial paralysis**, often accompanied by **painful vesicular rash** in the ear or mouth, and sometimes **hearing loss** or **vertigo** [1]. *a. V* - Cranial nerve V, the **trigeminal nerve**, is responsible for **facial sensation** and **mastication**. - While **trigeminal neuralgia** can cause severe facial pain, it is not primarily affected in Ramsay Hunt syndrome, nor does it cause facial paralysis. *d. IX* - Cranial nerve IX, the **glossopharyngeal nerve**, is involved in **taste** from the posterior tongue, **swallowing**, and **salivation**. - Involvement of this nerve typically manifests as issues with taste or difficulty swallowing, which are not hallmark features of Ramsay Hunt syndrome. *c. VIII* - Cranial nerve VIII, the **vestibulocochlear nerve**, is responsible for **hearing** and **balance**. - While Ramsay Hunt syndrome can sometimes affect the vestibulocochlear nerve leading to hearing loss or vertigo, the primary and most commonly involved nerve causing the characteristic facial paralysis is the facial nerve (VII).
Question 2: The facial nerve's first branch is?
- A. Greater petrosal nerve (Correct Answer)
- B. Lesser petrosal nerve
- C. Chorda tympani nerve
- D. Nerve to stapedius
Explanation: ***Greater petrosal nerve*** - The **greater petrosal nerve** is the **first major branch** of the facial nerve, emerging from the geniculate ganglion. - It carries **preganglionic parasympathetic fibers** to the pterygopalatine ganglion, which innervates the lacrimal gland and glands of the nasal and palatal mucosa. *Lesser petrosal nerve* - The **lesser petrosal nerve** originates from the **glossopharyngeal nerve (CN IX)**, not the facial nerve. - It carries parasympathetic fibers to the **otic ganglion**, supplying the parotid gland. *Chorda tympani nerve* - The **chorda tympani nerve** is a branch of the facial nerve that arises within the **temporal bone**, but it is not the *first* branch. - It carries **taste fibers** from the anterior two-thirds of the tongue and **preganglionic parasympathetic fibers** to the submandibular and sublingual glands. *Nerve to stapedius* - The **nerve to stapedius** branches off the facial nerve within the facial canal, innervating the **stapedius muscle**. - It is a very small motor branch and arises **after** the greater petrosal nerve.
Question 3: Herpes zoster in geniculate ganglion causes?
- A. Melkersson-Rosenthal syndrome
- B. Ramsay Hunt syndrome (Correct Answer)
- C. Bell's palsy
- D. Ophthalmic zoster
Explanation: ***Ramsay Hunt syndrome*** - This syndrome is caused by the **reactivation of varicella-zoster virus (VZV)** within the **geniculate ganglion**, leading to inflammation of the facial nerve (cranial nerve VII). - Key features include **ipsilateral facial paralysis**, **ear pain**, and a **vesicular rash in the external auditory canal** or on the auricle. *Melkersson-Rosenthal syndrome* - This is a rare neurological disorder characterized by a triad of symptoms: **recurrent facial paralysis**, **persistent orofacial swelling**, and **fissured tongue**. - It is not directly related to viral infection or the geniculate ganglion. *Bell's palsy* - Bell's palsy is an **idiopathic facial paralysis** that results from inflammation of the facial nerve, but the exact cause is unknown and it does not involve a vesicular rash. - While it shares some symptoms with Ramsay Hunt syndrome, the **absence of vesicles** distinguishes it. *Ophthalmic zoster* - Ophthalmic zoster occurs when VZV reactivates in the **trigeminal ganglion** (cranial nerve V), specifically affecting the ophthalmic division. - It presents with a **vesicular rash on the forehead, eyelids, and nose** (Hutchinson's sign), and can lead to serious ocular complications, but does not involve the facial nerve directly.
Question 4: A 40-year-old man presents with sudden onset of unilateral facial paralysis. He is unable to close his eye or raise his eyebrow. What is the most likely diagnosis?
- A. Myasthenia gravis
- B. Trigeminal neuralgia
- C. Bell's palsy (Correct Answer)
- D. Stroke
Explanation: ***Bell's palsy*** - **Bell's palsy** presents as an **idiopathic, sudden-onset, unilateral facial nerve paralysis** affecting both the upper and lower face (inability to close eye or raise eyebrow). - This condition is thought to be due to **inflammation or compression of the facial nerve (CN VII)**, leading to a complete hemifacial weakness or paralysis [2]. *Myasthenia gravis* - **Myasthenia gravis** is an **autoimmune disorder** primarily affecting the **neuromuscular junction**, causing fluctuating muscle weakness that worsens with activity and improves with rest. - While it can affect facial muscles, it typically presents with **ptosis**, **diplopia**, and generalized weakness, not an acute unilateral paralysis of the entire hemiface. *Trigeminal neuralgia* - **Trigeminal neuralgia** is characterized by **brief, severe, electric shock-like pains** in the distribution of the **trigeminal nerve (CN V)**, often triggered by touch or movement. - It does not cause muscle weakness or paralysis, but rather sensory symptoms and pain. *Stroke* - A **stroke** causing facial paralysis typically results in **sparing of the forehead** (the patient can still raise their eyebrow) because the upper facial muscles receive bilateral cortical innervation [1]. - While a stroke can cause sudden unilateral weakness, the inability to raise the eyebrow is a key differentiating feature making Bell's palsy more likely [2].
Question 5: In a case of unilateral supranuclear lesion of the facial nerve, which part of the face is affected?
- A. No part of the face
- B. Only ipsilateral upper part of the face is affected
- C. Only contralateral lower part of the face is affected (Correct Answer)
- D. Whole of the lower face is affected
Explanation: ***Only contralateral lower part of the face is affected*** [1] - The **upper part of the face** receives **bilateral innervation** from both cerebral hemispheres, meaning it is spared in a unilateral supranuclear lesion [1]. - The **lower part of the face** receives **contralateral innervation** only, leading to weakness on the opposite side of the lesion [1]. *No part of the face* - This is incorrect because a **supranuclear lesion** of the facial nerve definitively impacts motor control, specifically affecting the contralateral lower face. - Such lesions disrupt the corticobulbar tracts, leading to noticeable **motor deficits** [2]. *Only ipsilateral upper part of the face is affected* - This is incorrect because the **upper face** has **bilateral cortical innervation**, which means a unilateral supranuclear lesion typically spares it [1]. - Also, the weakness would be on the **contralateral side**, not the ipsilateral side, if any part of the face were affected. *Whole of the lower face is affected* - This is partially correct in that the lower face is affected, but it fails to specify that the involvement is **contralateral** to the lesion. - Specifying "whole of the lower face" lacks the anatomical precision regarding laterality and the sparing of the upper face due to bilateral innervation.
Question 6: Most common cause of facial nerve palsy is -
- A. Sarcoidosis
- B. Acoustic neuroma
- C. VZV
- D. Bell's Palsy (Correct Answer)
Explanation: ***Bell's Palsy*** - **Bell's Palsy** is the most common cause of **unilateral facial nerve palsy**, accounting for approximately 70% of all cases. It is an **idiopathic** condition, meaning its exact cause is unknown, but it is often linked to viral infections like HSV-1 [1]. - It presents as an **acute onset of facial muscle weakness or paralysis** on one side, involving both the upper and lower face. Unlike Bell's palsy, lesions with an upper motor neuron origin partly spare the upper face [1]. *Sarcoidosis* - **Sarcoidosis** can cause facial nerve palsy, but it is a relatively uncommmon etiology, often associated with other systemic symptoms like **uveitis** or **parotid enlargement**. - Facial palsy in sarcoidosis is part of a broader neurological manifestation and is much less frequent than Bell's Palsy. *Acoustic neuroma* - An **acoustic neuroma** (vestibular schwannoma) is a tumor that grows on the **vestibulocochlear nerve (CN VIII)**. It typically causes hearing loss, tinnitus, and balance issues [2]. - While it can eventually affect the facial nerve (CN VII) due to its proximity, facial nerve involvement is usually *not* the primary or most common presenting symptom, nor is it the most common cause of facial nerve palsy overall [2]. *VZV* - **Varicella-zoster virus (VZV)** infection can cause facial nerve palsy in the form of **Ramsay Hunt syndrome (Herpes zoster oticus)**. This is characterized by facial palsy accompanied by a painful **vesicular rash** in the ear canal or on the auricle. - While a significant cause of facial palsy, it is less common than Bell's Palsy and has distinct associated symptoms.
Question 7: Facial nerve palsy at stylomastoid foramen can cause-
- A. Loss of taste sensation in anterior 2/3 of ipsilateral tongue
- B. Loss of lacrimation at side of lesion
- C. Hyperacusis
- D. Loss of corneal reflex at side of lesion (Correct Answer)
Explanation: ***Loss of corneal reflex at side of lesion*** - The **corneal reflex** involves the ophthalmic division of the trigeminal nerve (afferent limb) and the facial nerve (efferent limb) for ipsilateral orbicularis oculi contraction. - A facial nerve palsy at the stylomastoid foramen impairs the efferent component, preventing the **closure of the eyelid** on the affected side [1]. *Loss of taste sensation in anterior 2/3 of ipsilateral tongue* - **Taste sensation** from the anterior two-thirds of the tongue is carried by the **chorda tympani nerve**, which branches off the facial nerve *before* the stylomastoid foramen. - Therefore, a lesion at the stylomastoid foramen would occur *distal* to the origin of the chorda tympani, preserving taste. *Loss of lacrimation at side of lesion* - **Lacrimation** is mediated by the **greater petrosal nerve**, which is a branch of the facial nerve originating *proximal* to the geniculate ganglion. - A lesion at the stylomastoid foramen would be well *after* the greater petrosal nerve has branched off, so lacrimation would be unaffected. *Hyperacusis* - **Hyperacusis** (increased sensitivity to sound) results from paralysis of the **stapedius muscle**, which is innervated by the nerve to stapedius. - The nerve to stapedius branches off the facial nerve *within the temporal bone*, *before* the stylomastoid foramen, so a lesion at the stylomastoid foramen would not cause hyperacusis.
Question 8: Mark the false statement regarding nucleus of facial nerve :
- A. Bilateral innervation of forehead preserves its function in supranuclear lesions
- B. Motor nucleus of facial nerve is situated in pons
- C. Upper part of the nucleus receives fibres from both the cerebral hemispheres
- D. Lower part of nucleus gets uncrossed fibres from ipsilateral hemisphere (Correct Answer)
Explanation: ***Lower part of nucleus gets uncrossed fibres from ipsilateral hemisphere*** - This statement is false because the **lower part of the facial nucleus**, which innervates the muscles of the lower face, primarily receives **crossed fibers from the contralateral cerebral hemisphere** [1]. - It does not receive uncrossed fibers from the ipsilateral hemisphere. *Bilateral innervation of forehead preserves its function in supranuclear lesions* - The **upper part of the facial nucleus**, responsible for innervating the muscles of the forehead and upper face, receives **bilateral innervation** from both cerebral hemispheres [1]. - Therefore, in a **supranuclear lesion** (e.g., stroke affecting the motor cortex), the forehead muscles are spared due to this bilateral input, while the lower face is paralyzed [1]. *Motor nucleus of facial nerve is situated in pons* - The main **motor nucleus of the facial nerve (CN VII)** is indeed located in the **pontine tegmentum** of the brainstem [1]. - It is one of the distinct nuclei associated with the facial nerve, along with the superior salivatory and lacrimal nuclei. *Upper part of the nucleus receives fibres from both the cerebral hemispheres* - The **upper part of the facial motor nucleus** receives **corticonuclear fibers from both the ipsilateral and contralateral cerebral hemispheres** [1]. - This bilateral innervation is crucial for preserving upper facial muscle function in unilateral upper motor neuron lesions [1].
Question 9: True about acoustic neuroma:
- A. Arises from vestibular nerve (Correct Answer)
- B. Malignant tumour
- C. Upper pole compresses IX,X,XI nerves
- D. Lower pole compresses trigeminal cranial nerve
Explanation: ***Arises from vestibular nerve*** - An **acoustic neuroma**, also known as a **vestibular schwannoma**, is a benign tumor that originates from the **Schwann cells** of the **vestibular nerve (cranial nerve VIII)**. - This tumor typically grows in the **internal auditory canal** and cerebellopontine angle. *Malignant tumour* - Acoustic neuromas are almost always **benign tumors**, meaning they are non-cancerous and do not typically spread to other parts of the body. - While they are benign, their growth can compress adjacent nerves and brain structures, leading to significant neurological deficits. *Upper pole compresses IX,X,XI nerves* - The **glossopharyngeal (IX), vagus (X), and accessory (XI) nerves** originate lower in the brainstem and are more commonly compressed by tumors in the **jugular foramen** region, not typically by the upper pole of an acoustic neuroma. - An acoustic neuroma primarily affects the **vestibulocochlear nerve (VIII)** and, if large enough, the **facial nerve (VII)** and **trigeminal nerve (V)** in the **cerebellopontine angle**. *Lower pole compresses trigeminal cranial nerve* - The **trigeminal nerve (V)** is located more superiorly and medially in the **cerebellopontine angle** relative to the usual growth pattern of an acoustic neuroma. - Compression of the trigeminal nerve by an acoustic neuroma is more likely to occur with a **large tumor** expanding into the superior part of the cerebellopontine angle, rather than by its lower pole.
Question 10: During acute tonsillitis, referred pain from the tonsil to the middle ear occurs via which nerve?
- A. Facial nerve
- B. Glossopharyngeal nerve (Correct Answer)
- C. Trigeminal nerve
- D. Vagus nerve
Explanation: ***Glossopharyngeal nerve*** - The **glossopharyngeal nerve (CN IX)** provides sensory innervation to the palatine tonsil via its tonsillar branches - CN IX also supplies the middle ear via the **tympanic nerve (Jacobson's nerve)**, which forms the tympanic plexus - This shared sensory pathway explains **referred otalgia** (ear pain) during acute tonsillitis - Inflammation of the tonsil stimulates CN IX, and the brain misinterprets this as pain from the middle ear *Facial nerve* - The **facial nerve (CN VII)** primarily provides motor innervation to muscles of facial expression and taste to the anterior two-thirds of the tongue - While it has a small sensory component (nervus intermedius) for the external auditory canal, it does not innervate the tonsil - Cannot serve as the pathway for referred pain from tonsil to middle ear *Trigeminal nerve* - The **trigeminal nerve (CN V)** provides sensory innervation to the face, anterior scalp, and oral cavity - Does not innervate the palatine tonsil or the middle ear cavity - Not involved in tonsillar referred otalgia *Vagus nerve* - The **vagus nerve (CN X)** provides sensory innervation to parts of the pharynx, larynx, and external auditory canal (via Arnold's nerve) - While it contributes to pharyngeal sensation, the **glossopharyngeal nerve is the primary pathway** for referred otalgia from tonsillar inflammation due to its direct innervation of both the tonsil and middle ear
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