Vocal Fold Structure and Function — MCQs
A patient presents with hoarseness and laryngoscopy reveals a warty, cauliflower-like growth on the vocal cord. Identify the most likely lesion.
Reinke's layer is seen in:
Which of the following changes in voice is not produced as a result of external laryngeal nerve injury post thyroidectomy?
Which of the following muscles is responsible for abduction of the vocal cord?
During thyroidectomy, damage to which nerve leads to loss of high-pitched voice?
Most common nerve injured in ligation of inferior thyroid artery
Dysphonia plica ventricularis is produced from:
A singer presents with difficulty singing at a high pitch. On examination, bowing of the vocal cord is observed on the right side. Which of the following muscles has likely been compromised?
The voice is not affected in which of the following conditions?
A patient complains of sharp shooting pain in the pharynx and tonsil. On examination, a trigger zone is found in the tonsillar area. What is the diagnosis?
Vocal Fold Structure and Function Indian Medical PG Practice Questions and MCQs
Question 1: A patient presents with hoarseness and laryngoscopy reveals a warty, cauliflower-like growth on the vocal cord. Identify the most likely lesion.
- A. Laryngeal papilloma (Correct Answer)
- B. Laryngeal malignancy
- C. Tracheomalacia
- D. Reinke’s edema
Explanation: ***Laryngeal papilloma*** - **Hoarseness** and a **warty, cauliflower-like growth** on the vocal cord are classic descriptions of a laryngeal papilloma, often caused by **HPV infection**. - These lesions can be solitary or multiple, and while benign, they can recur and cause voice changes and respiratory obstruction. *Laryngeal malignancy* - While hoarseness is a common symptom of laryngeal malignancy, the description of a **"warty, cauliflower-like growth"** is more characteristic of a papilloma than most typical carcinomas, which might appear more ulcerative or infiltrative. - Malignancies are more commonly associated with risk factors like **smoking and alcohol use**, and often present with other symptoms like dysphagia or weight loss. *Tracheomalacia* - **Tracheomalacia** refers to softening of the tracheal cartilage, leading to airway collapse, typically causing stridor or respiratory distress. - It does not present as a **discrete growth** on the vocal cords but rather as a diffuse structural weakness of the trachea. *Reinke’s edema* - **Reinke's edema** (polypoid corditis) is characterized by a **gelatinous or fluid-filled swelling** of the vocal cords, usually associated with chronic irritation like smoking. - It presents as a swollen, boggy appearance of the vocal cords, not a warty or cauliflower-like growth.
Question 2: Reinke's layer is seen in:
- A. Vocal cord (Correct Answer)
- B. Tympanic membrane
- C. Cochlea
- D. Reissner's membrane
Explanation: ***Vocal cord*** - **Reinke's space**, also known as Reinke's layer, is the superficial layer of the **lamina propria** of the vocal cord. - This layer is crucial for the **vibration of the vocal folds**, which is essential for sound production. *Tympanic membrane* - The **tympanic membrane**, or eardrum, is a thin membrane that separates the external ear from the middle ear [1]. [2]. - It vibrates in response to **sound waves** and transmits these vibrations to the ossicles, playing a role in hearing, not vocalization [1], [2]. *Cochlea* - The **cochlea** is a spiral-shaped cavity in the inner ear involved in the sense of hearing [2]. - It contains the **organ of Corti**, which converts sound vibrations into nerve impulses but has no connection to vocal cord anatomy [2]. *Reissner's membrane* - **Reissner's membrane** (vestibular membrane) is a thin membrane that separates the scala vestibuli from the scala media within the cochlea. - Its primary function is to maintain the **composition of the endolymph** in the scala media, and it is part of the auditory system, not the larynx.
Question 3: Which of the following changes in voice is not produced as a result of external laryngeal nerve injury post thyroidectomy?
- A. Inability to sing at higher ranges
- B. Poor volume and projection
- C. Hoarseness (Correct Answer)
- D. Voice fatigue
Explanation: ***Hoarseness*** - **Hoarseness** is primarily caused by injury to the **recurrent laryngeal nerve (RLN)**, which innervates most intrinsic laryngeal muscles responsible for vocal cord adduction and abduction. - An external laryngeal nerve (ELN) injury affects the **cricothyroid muscle**, leading to less tension on the vocal cords, but typically not frank hoarseness. *Voice fatigue* - Injury to the external laryngeal nerve (ELN) weakens the **cricothyroid muscle**, which is responsible for tensing and elongating the vocal cords. - This weakness leads to greater effort required to maintain vocal quality, resulting in **voice fatigue**. *Inability to sing at higher ranges* - The **cricothyroid muscle**, innervated by the ELN, is crucial for increasing vocal cord tension. - Increased tension is necessary for adjusting vocal pitch and reaching **higher frequencies** or notes. *Poor volume and projection* - The cricothyroid muscle's role in vocal cord tension contributes to the efficiency of vocal fold vibration. - Reduced tension due to ELN injury can lead to decreased **vocal power and projection**.
Question 4: Which of the following muscles is responsible for abduction of the vocal cord?
- A. Posterior cricoarytenoid (Correct Answer)
- B. Transverse arytenoid
- C. Lateral cricoarytenoid
- D. Cricothyroid muscle
Explanation: ***Posterior cricoarytenoid*** - This is the **only intrinsic laryngeal muscle** responsible for **abduction** (opening) of the vocal cords. - Contraction of this muscle causes the **arytenoid cartilages** to rotate laterally, separating the vocal folds. *Lateral cricoarytenoid* - This muscle is responsible for **adduction** (closing) of the vocal cords, thereby narrowing the **rima glottidis**. - Its contraction rotates the arytenoid cartilages medially. *Cricothyroid muscle* - This muscle is the primary tensor of the vocal cords, responsible for **increasing the pitch of the voice**. - It stretches the vocal cords by tilting the **thyroid cartilage** forward and downward. *Transverse arytenoid* - This muscle is an **adductor** of the vocal cords, helping to close them by drawing the **arytenoid cartilages** together. - It works with the oblique arytenoid muscles to approximate the arytenoids.
Question 5: During thyroidectomy, damage to which nerve leads to loss of high-pitched voice?
- A. External branch of the superior laryngeal nerve (Correct Answer)
- B. Hypoglossal nerve
- C. Vagus nerve
- D. Recurrent laryngeal nerve
Explanation: ***External branch of the superior laryngeal nerve*** - The **external branch of the superior laryngeal nerve** innervates the **cricothyroid muscle**, which is responsible for tensing the vocal cords. - Damage to this nerve paralyzes the cricothyroid muscle, leading to an inability to tense the vocal cords, resulting in a **monotonous voice** and **loss of high-pitched tones**. *Hypoglossal nerve* - The **hypoglossal nerve (CN XII)** controls the muscles of the **tongue**, affecting articulation and swallowing, but not vocal pitch directly. - Damage primarily causes **tongue deviation** and **difficulty with speech (dysarthria)** and swallowing. *Vagus nerve* - The **vagus nerve (CN X)** gives rise to both the **superior laryngeal nerve** and the **recurrent laryngeal nerve**. - While damage to the vagus nerve trunk would affect vocalization, the question specifically asks about loss of high-pitched voice, which points to a more localized injury to one of its branches. *Recurrent laryngeal nerve* - The **recurrent laryngeal nerve** innervates most of the intrinsic laryngeal muscles, including the **thyroarytenoid** and **posterior cricoarytenoid muscles**, primarily affecting vocal cord adduction and abduction. - Damage typically causes **hoarseness** due to vocal cord paralysis, and in severe cases, difficulty breathing, but it does not specifically lead to the *loss of high-pitched voice* as directly as superior laryngeal nerve damage.
Question 6: Most common nerve injured in ligation of inferior thyroid artery
- A. Sympathetic trunk
- B. Phrenic nerve
- C. Recurrent laryngeal nerve (Correct Answer)
- D. External branch of superior laryngeal nerve
Explanation: **Recurrent laryngeal nerve** - The **recurrent laryngeal nerve (RLN)** runs in close proximity to the inferior thyroid artery, especially on the right side, making it highly vulnerable during ligation or thyroid surgery. - Injury to the RLN can cause **hoarseness** due to paralysis of the vocal cords, as it innervates most intrinsic laryngeal muscles. *Sympathetic trunk* - The **sympathetic trunk** lies more medially and posteriorly in the neck, generally not in the immediate surgical field for inferior thyroid artery ligation. - Injury to the sympathetic trunk typically leads to **Horner's syndrome** (ptosis, miosis, anhidrosis). *Phrenic nerve* - The **phrenic nerve** courses over the anterior scalene muscle, lateral to the thyroid gland and major vessels, making it relatively safe during standard thyroid surgery. - Damage to the phrenic nerve would result in **diaphragmatic paralysis** and respiratory compromise. *External branch of superior laryngeal nerve* - The **external branch of the superior laryngeal nerve (EBSLN)** is located more superiorly, running with the superior thyroid artery to the cricothyroid muscle. - Injury to the EBSLN would affect the **pitch of the voice** but is less commonly injured during inferior thyroid artery ligation compared to the RLN.
Question 7: Dysphonia plica ventricularis is produced from:
- A. Vocal cord
- B. Ventricular fold (Correct Answer)
- C. Arytenoid
- D. Epiglottis
Explanation: ***Ventricular fold*** - **Dysphonia plica ventricularis**, also known as **ventricular dysphonia** or **false vocal cord dysphonia**, occurs when the **ventricular folds** (false vocal cords) vibrate inappropriately during phonation. - This condition often results in a **hoarse**, rough, or strained voice quality, as the false vocal cords are not designed for regular vibratory function in voice production. *Vocal cord* - The **true vocal cords** are the primary structures responsible for producing sound through precise vibration and approximation during phonation. - Dysphonia originating from the **true vocal cords** would typically be described by terms like vocal fold paralysis, nodules, or polyps, not "plica ventricularis." *Arytenoid* - The **arytenoid cartilages** are crucial in vocal cord movement and tension through their articulation with the cricoid cartilage. - While they influence voice production, they do not directly vibrate to produce sound themselves; rather, they position the vocal cords. *Epiglottis* - The **epiglottis** is a leaf-shaped cartilage that primarily functions to prevent food and liquid from entering the trachea during swallowing. - It plays no direct role in voice generation through vibration; its involvement in phonation is generally limited to resonance or protection.
Question 8: A singer presents with difficulty singing at a high pitch. On examination, bowing of the vocal cord is observed on the right side. Which of the following muscles has likely been compromised?
- A. Posterior cricoarytenoid
- B. Lateral cricoarytenoid
- C. Cricothyroid (Correct Answer)
- D. Thyroarytenoid
Explanation: ***Cricothyroid*** - The **cricothyroid muscle** is primarily responsible for **tensioning and elongating the vocal cords**, which is crucial for increasing vocal pitch. - Damage to this muscle or its innervation (superior laryngeal nerve) results in an inability to reach higher pitches and can cause **vocal cord bowing** due to reduced tension. *Posterior cricoarytenoid* - This muscle is the **primary abductor** of the vocal cords, meaning it opens the vocal cords for breathing. - Compromise would lead to difficulty breathing or a paralyzed vocal cord in the adducted position, not bowing with difficulty singing high notes. *Lateral cricoarytenoid* - The **lateral cricoarytenoid muscle** is a **vocal cord adductor** and rotator, bringing the vocal cords together to regulate voice intensity. - Dysfunction typically results in a weak and breathy voice, or difficulty bringing the cords together, not specifically difficulty with high pitch. *Thyroarytenoid* - The **thyroarytenoid muscle** (which includes the vocalis muscle) acts to **relax and shorten the vocal cords**, lowering pitch and modulating vocal cord tension. - Dysfunction would primarily lead to difficulty with lower pitches or a hoarse voice, as it prevents proper relaxation of the vocal cords.
Question 9: The voice is not affected in which of the following conditions?
- A. Unilateral abductor palsy (Correct Answer)
- B. Unilateral adductor palsy
- C. Partial abductor palsy
- D. Total adductor palsy
Explanation: In phoniatrics, the quality of voice depends on the ability of the vocal cords to meet in the midline (**adduction**) for vibration. ### **Explanation of the Correct Answer** **A. Unilateral abductor palsy:** In this condition, the affected vocal cord is paralyzed in the **median (midline) position** because it cannot move outward (abduct). Since the paralyzed cord is already at the midline, the healthy cord can easily meet it during phonation. As a result, the glottic gap is closed perfectly, and the **voice remains normal**. This condition is often asymptomatic and may only present with mild exertional dyspnea (stridor). ### **Why the Other Options are Incorrect** * **B. Unilateral adductor palsy:** The affected cord remains in the **paramedian or lateral position** and cannot move to the midline. This creates a large glottic gap during speech, leading to a **breathy, weak voice (hoarseness)**. * **C. Partial abductor palsy:** According to **Semon’s Law**, in progressive lesions of the recurrent laryngeal nerve, abductor fibers are injured first. This results in the cord being stuck in a position that interferes with the symmetry of vibration, leading to varying degrees of **hoarseness**. * **D. Total adductor palsy:** This involves a complete failure of the cords to approximate, leading to significant **aphonia** (loss of voice) or severe breathiness. ### **Clinical Pearls for NEET-PG** * **Semon’s Law:** In progressive recurrent laryngeal nerve (RLN) injury, abductors (Posterior Cricoarytenoid) are paralyzed before adductors. * **Wagner and Grossman Hypothesis:** If the Superior Laryngeal Nerve (SLN) is intact, the cricothyroid muscle keeps the paralyzed cord in the **paramedian** position. * **Position of Cords:** * Unilateral RLN palsy: Paramedian position. * Bilateral RLN palsy: Median/Paramedian (Airway emergency, but voice is often good). * Combined RLN + SLN palsy: **Cadaveric position** (Intermediate position).
Question 10: A patient complains of sharp shooting pain in the pharynx and tonsil. On examination, a trigger zone is found in the tonsillar area. What is the diagnosis?
- A. Sphenopalatine neuralgia
- B. Paratrigeminal neuralgia
- C. Glossopharyngeal neuralgia (Correct Answer)
- D. Trigeminal neuralgia
Explanation: **Explanation:** The clinical presentation of **sharp, shooting (paroxysmal) pain** localized to the **pharynx and tonsillar area**, initiated by a **trigger zone** in the tonsil, is the classic hallmark of **Glossopharyngeal Neuralgia**. **1. Why Glossopharyngeal Neuralgia is correct:** This condition involves the 9th cranial nerve. The pain is typically unilateral and occurs in the distribution of the glossopharyngeal nerve (posterior third of the tongue, tonsillar fossa, pharynx, and beneath the angle of the jaw). Common triggers include swallowing, talking, coughing, or touching the tonsillar area. **2. Why other options are incorrect:** * **Sphenopalatine neuralgia (Sluder’s Neuralgia):** Characterized by pain in the lower face, nose, and orbit, often associated with nasal congestion or rhinorrhea, rather than pharyngeal triggers. * **Paratrigeminal neuralgia (Raeder’s Syndrome):** Presents as trigeminal pain (usually V1/V2 distribution) accompanied by oculosympathetic palsy (Horner’s syndrome). * **Trigeminal neuralgia (Tic Douloureux):** The most common facial neuralgia, but the pain is located in the distribution of the 5th cranial nerve (usually maxillary or mandibular branches). Trigger zones are typically on the skin of the face or the gingiva, not the pharynx. **High-Yield Clinical Pearls for NEET-PG:** * **Eagle’s Syndrome:** A key differential diagnosis where an elongated styloid process irritates the glossopharyngeal nerve, causing similar pain. * **Treatment:** Medical management is the first line, primarily using **Carbamazepine**. * **Surgical Management:** If medical therapy fails, **Microvascular Decompression (MVD)** of the 9th nerve or rhizotomy is performed. * **Vagal Association:** In rare cases, glossopharyngeal neuralgia can trigger the carotid sinus reflex, leading to bradycardia or syncope.
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