Otolaryngology Basics Practice Questions

Q: Which nerve is responsible for referred pain in the ear?

Glossopharyngeal. ### Explanation The sensory innervation of the ear is complex, involving multiple cranial and spinal nerves. This complexity is the basis for **referred otalgia** (ear pain originating from a non-otologic source). **Why Glossopharyngeal (CN IX) is Correct:** The Glossopharyngeal nerve supplies sensory innervation to the middle ear cleft via the **Jacobson’s nerve** (tympanic branch). It also provides sensation to the oropharynx, base of the tongue, and tonsillar fossa. Due to this shared pathway, pathologies in the throat—most commonly **post-tonsillectomy pain, peritonsillar abscess (Quinsy), or glossopharyngeal neuralgia**—are perceived as pain in the ear. **Analysis of Incorrect Options:** * **A. Trochlear (CN IV):** A pure motor nerve supplying the superior oblique muscle of the eye. It has no sensory component or connection to the ear. * **B. Olfactory (CN I):** A special sensory nerve responsible for the sense of smell. It does not carry general somatic sensation. * **D. Abducent (CN VI):** A pure motor nerve supplying the lateral rectus muscle of the eye. It is not involved in sensory pathways. **Clinical Pearls for NEET-PG:** 1. **Nerves causing referred otalgia:** * **CN V3 (Auriculotemporal n.):** Pain from TMJ disorders or dental caries. * **CN IX (Jacobson’s n.):** Pain from the oropharynx/tonsils. * **CN X (Arnold’s n.):** Pain from the larynx or pyriform fossa (e.g., Laryngeal Malignancy). * **C2, C3 (Greater Auricular n.):** Pain from cervical spine issues. 2. **Hilger’s Law:** Any nerve that supplies a muscle also supplies the joint moved by the muscle and the skin over the insertion. 3. **High-Yield Fact:** If a patient presents with ear pain but a **normal-looking tympanic membrane**, always examine the throat and larynx to rule out occult malignancy.

Q: Which of the following muscles is supplied by the external laryngeal nerve, a branch of the superior laryngeal nerve?

Cricothyroid. **Explanation:** The nerve supply of the laryngeal muscles is a high-yield topic for NEET-PG. The larynx is supplied by two branches of the **Vagus nerve (CN X)**: the Superior Laryngeal Nerve (SLN) and the Recurrent Laryngeal Nerve (RLN). 1. **Why Cricothyroid is correct:** The **External Laryngeal Nerve** (a branch of the SLN) provides motor innervation to only one muscle: the **Cricothyroid**. This muscle acts as a tensor of the vocal cords by tilting the thyroid cartilage forward, thereby increasing the distance between the thyroid and arytenoid cartilages. 2. **Why other options are incorrect:** All other intrinsic muscles of the larynx (Options A, C, and D) are supplied by the **Recurrent Laryngeal Nerve**. * **Posterior cricoarytenoid:** The sole abductor of the vocal cords (the "safety muscle"). * **Lateral cricoarytenoid:** An adductor of the vocal cords. * **Thyroarytenoid:** Relaxes the vocal cords (its medial fibers form the Vocalis muscle). **Clinical Pearls for NEET-PG:** * **The "Rule of All":** All intrinsic muscles of the larynx are supplied by the RLN *except* the Cricothyroid (External SLN). * **Sensory Supply:** The **Internal Laryngeal Nerve** (the other branch of the SLN) provides sensory innervation to the larynx *above* the vocal cords. The RLN provides sensory innervation *below* the vocal cords. * **Surgical Significance:** During thyroidectomy, the External Laryngeal Nerve is at risk during ligation of the **Superior Thyroid Artery** due to their close proximity. Injury leads to a weak, husky voice and loss of high-pitched notes.

Q: A patient with facial nerve paralysis suffers from inability to dampen loud noises due to denervation of which muscle?

Stapedius. **Explanation:** The correct answer is **Stapedius**. This muscle is responsible for the **acoustic reflex** (stapedial reflex), which protects the inner ear from acoustic trauma. **1. Why Stapedius is correct:** The stapedius muscle is the smallest skeletal muscle in the body, located in the middle ear. It is innervated by the **nerve to stapedius**, a branch of the **Facial Nerve (CN VII)**. When exposed to loud sounds (>70-90 dB), the stapedius contracts, pulling the stapes bone away from the oval window. This increases the stiffness of the ossicular chain, dampening the vibrations transmitted to the cochlea. In facial nerve paralysis (e.g., Bell’s palsy), denervation of this muscle leads to **hyperacusis**—a condition where normal sounds appear abnormally loud and painful. **2. Why other options are incorrect:** * **Posterior belly of digastric & Stylohyoid:** While both are supplied by the facial nerve, they are muscles of the neck involved in swallowing and stabilizing the hyoid bone; they have no role in hearing. * **Tensor tympani:** This muscle also dampens sound by tensing the tympanic membrane, but it is innervated by the **Mandibular nerve (V3)**, a branch of the Trigeminal nerve. It would not be affected by a primary facial nerve lesion. **Clinical Pearls for NEET-PG:** * **Hyperacusis** indicates a facial nerve lesion **proximal** to the nerve to stapedius (in the vertical segment of the bony fallopian canal). * The **Stapedial Reflex** is an objective test used in topodiagnostic studies to locate the site of a facial nerve lesion. * The stapedius muscle is derived from the **2nd branchial arch**, whereas the tensor tympani is derived from the **1st branchial arch**.

Q: Topical mitomycin C is used to aid which of the following treatments?

Treatment of laryngotracheal stenosis. **Explanation:** **Mitomycin C (MMC)** is a potent chemotherapeutic agent derived from *Streptomyces caespitosus*. In ENT, it is used topically for its ability to inhibit **fibroblast proliferation** and protein synthesis, thereby preventing the formation of excessive scar tissue (fibrosis). 1. **Why Option B is Correct:** In **Laryngotracheal Stenosis**, the primary challenge is the recurrence of narrowing due to exuberant granulation tissue and scarring after surgical dilation or resection. Topical application of MMC (typically 0.4 mg/ml) to the denuded area post-surgery inhibits collagen synthesis, maintaining the patency of the airway and reducing the rate of restenosis. 2. **Why Other Options are Incorrect:** * **A. Angiofibroma:** This is a highly vascular benign tumor. Treatment is primarily surgical excision (often with preoperative embolization). MMC has no role in managing vascular tumors. * **C. Skull Base Osteomyelitis:** This is a severe infection (usually fungal or bacterial). Treatment requires long-term systemic antibiotics/antifungals and surgical debridement, not anti-proliferative agents. * **D. Sturge-Weber Syndrome:** This is a neurocutaneous disorder characterized by port-wine stains and vascular malformations. MMC does not address the underlying vascular pathology. **High-Yield Clinical Pearls for NEET-PG:** * **Other ENT uses of MMC:** Used in **Dacryocystorhinostomy (DCR)** to prevent closure of the osteotomy site, in **Choanal Atresia** surgery, and during **Myringotomy** to keep the perforation patent longer. * **Mechanism:** It acts as an alkylating agent that cross-links DNA. * **Application:** It is applied topically via a soaked cottonoid for a brief period (usually 2–5 minutes) to minimize systemic toxicity.

Q: In 20% to 50% of cases, the COC is associated with an unerupted or impacted tooth. The tooth most commonly being:

Canine. **Explanation:** The **Calcifying Odontogenic Cyst (COC)**, also known as the **Gorlin Cyst**, is a unique lesion that exhibits features of both a cyst and a solid neoplasm. A key diagnostic feature of COC is its frequent association with odontomas or impacted teeth. **1. Why Canine is Correct:** Statistically, in cases where a COC is associated with an impacted tooth (approximately 20% to 50% of cases), the **maxillary or mandibular canine** is the most frequently involved tooth. This association occurs because COCs often develop in the anterior segments of the jaws (incisor-canine region), where canine impaction is clinically prevalent. The cyst typically surrounds the crown of the unerupted tooth, mimicking a dentigerous cyst radiographically. **2. Why Other Options are Incorrect:** * **Incisors:** While COCs are commonly found in the anterior jaw, the rate of impaction for incisors is significantly lower than that of canines. * **Premolars & Molars:** These teeth are more commonly associated with other odontogenic lesions, such as Dentigerous cysts or Ameloblastomas. While a COC can occur in the posterior mandible, it is less frequent than the anterior location. **3. Clinical Pearls for NEET-PG:** * **Histopathology:** The hallmark of COC is the presence of **"Ghost Cells"** (eosinophilic cells without nuclei) and focal areas of calcification. * **Radiology:** Appears as a well-defined unilocular radiolucency, often containing radiopaque flecks ("salt and pepper" appearance). * **Location:** Most common in the **maxilla** (65%) and usually occurs in the **anterior** region. * **Age:** Shows a bimodal age distribution (peak in the 2nd and 6th decades). * **Differential Diagnosis:** Must be distinguished from an Adenomatoid Odontogenic Tumor (AOT), which also favors the anterior maxilla and impacted canines.

Q: What is the lever ratio?

1.3:1. The middle ear acts as an impedance matching transformer to ensure sound energy is efficiently transferred from the air to the fluid-filled cochlea. Without this mechanism, 99.9% of sound energy would be reflected. The **Lever Ratio** is one of the two primary mechanisms contributing to this transformer action. ### Explanation of the Correct Answer **Option B (1.3:1) is correct.** The lever ratio is derived from the length of the handle of the **malleus** (approx. 9 mm) compared to the long process of the **incus** (approx. 7 mm). Because the malleus is 1.3 times longer than the incus, it acts as a physical lever, increasing the force of the sound vibrations at the stapes footplate by a factor of 1.3. ### Analysis of Incorrect Options * **Option A (14:1):** This is a distractor value and does not represent a standard middle ear ratio. * **Option C (18:1):** This refers to the **Areal Ratio** (Hydraulic Ratio). The effective vibrating area of the tympanic membrane (55 mm²) is about 17–18 times larger than the area of the stapes footplate (3.2 mm²). * **Option D (1.5:1):** While some older texts vary slightly, the standard accepted value for the lever ratio in human anatomy for competitive exams is 1.3:1. ### NEET-PG High-Yield Pearls * **Total Transformer Ratio:** This is the product of the Areal Ratio (18) and the Lever Ratio (1.3), which equals approximately **22:1**. * **Decibel Gain:** The transformer mechanism provides a pressure gain of about **25–30 dB**. * **Buckling Effect:** The conical shape of the tympanic membrane provides an additional doubling of force (2:1 ratio), further aiding impedance matching. * **Clinical Correlation:** In cases of ossicular chain disruption, this transformer action is lost, leading to a conductive hearing loss of approximately 30 dB.

Question 1

Which nerve is responsible for referred pain in the ear?

Accepted Answer

Glossopharyngeal

Answer

Trochlear

Answer

Olfactory

Answer

Abducent

Question 2

A 30-year-old female presented with stridor following an upper respiratory infection. Laryngoscopy shows a glottic gap of 3 mm. Which of the following is NOT a management option?

Accepted Answer

Type I thyroplasty

Answer

Tracheostomy

Answer

Type II thyroplasty

Answer

Cordectomy

Question 3

Which of the following muscles is supplied by the external laryngeal nerve, a branch of the superior laryngeal nerve?

Accepted Answer

Cricothyroid

Answer

Posterior cricoarytenoid

Answer

Lateral cricoarytenoid

Answer

Thyroarytenoid

Question 4

Which of the following conditions does not affect the voice?

Accepted Answer

Unilateral abductor palsy

Answer

Unilateral adductor palsy

Answer

Bilateral abductor palsy

Answer

Total adductor palsy

Question 5

A patient with facial nerve paralysis suffers from inability to dampen loud noises due to denervation of which muscle?

Accepted Answer

Stapedius

Answer

Posterior belly of digastric

Answer

Tensor tympani

Answer

Stylohyoid Muscle

Question 6

Which of the following statements regarding the facial nerve and its relations is FALSE?

Accepted Answer

The tympanic segment of the facial nerve is located below the round window and above the horizontal semicircular canal.

Answer

The processus cochleariformis serves as a landmark for the geniculate ganglion of the facial nerve.

Answer

The mastoid segment of the facial nerve is consistently situated posterior to the tympanomastoid suture.

Answer

A patient with a lesion between the geniculate ganglion and the nerve to the stapedius will experience phonophobia, loss of the stapedial reflex, and impaired taste sensation.

Question 7

Topical mitomycin C is used to aid which of the following treatments?

Accepted Answer

Treatment of laryngotracheal stenosis

Answer

Endoscopic treatment of angiofibroma

Answer

Skull base osteomyelitis

Answer

Sturge-Weber syndrome

Question 8

In 20% to 50% of cases, the COC is associated with an unerupted or impacted tooth. The tooth most commonly being:

Accepted Answer

Canine

Answer

Incisor

Answer

Premolar

Answer

Molar

Question 9

A patient with hoarseness of voice was found to be having pachydermia laryngis. All of the following are true except?

Accepted Answer

It is a hyperkeratotic lesion present within the anterior two-third of the vocal cords

Answer

It is not a premalignant lesion

Answer

Diagnosis is made by biopsy

Answer

On microscopy it shows acanthosis and hyperkeratosis

Question 10

What is the lever ratio?

Accepted Answer

1.3:1

Answer

14:01

Answer

18:01

Answer

1.5:1

Otolaryngology Basics — MCQs

Otolaryngology Basics — MCQs

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