Anatomy of the Larynx — 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?
Elastic cartilage is present in
Which of the following muscles is responsible for abduction of the vocal cord?
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?
Which of the following muscles is not affected by paralysis of the recurrent laryngeal nerve?
Which part of the larynx is most commonly involved in tuberculosis (TB)?
Which of the following statements about laryngomalacia is true?
Omega shaped epiglottis is typically seen in which of the following conditions?
Anatomy of the Larynx 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: Elastic cartilage is present in
- A. Epiglottis (Correct Answer)
- B. Cricoid
- C. Arytenoid cartilage
- D. Thyroid cartilage
Explanation: ***Epiglottis*** - The **epiglottis** is composed of **elastic cartilage**, which provides flexibility to fold over the glottis during swallowing, preventing food from entering the trachea. - This type of cartilage is characterized by a dense network of **elastic fibers** within its matrix, allowing it to spring back to its original shape. *Cricoid* - The **cricoid cartilage** is a ring-shaped cartilage that forms the inferior wall of the larynx and is composed of **hyaline cartilage**. - **Hyaline cartilage** provides structural support and maintains the patency of the airway, but lacks the flexibility of elastic cartilage. *Arytenoid cartilage* - The **arytenoid cartilages** are small, paired cartilages that sit atop the cricoid cartilage and are primarily composed of **hyaline cartilage**. - They play a crucial role in the movement of the **vocal cords**, but their limited flexibility is not characteristic of elastic cartilage. *Thyroid cartilage* - The **thyroid cartilage**, the largest laryngeal cartilage, forms the "Adam's apple" and is made of **hyaline cartilage**. - Its rigid structure provides protection for the vocal cords and maintains the shape of the larynx, which is a function of hyaline rather than elastic cartilage.
Question 5: 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 6: 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 7: Which of the following muscles is not affected by paralysis of the recurrent laryngeal nerve?
- A. Lateral cricoarytenoid
- B. Vocalis
- C. Thyroarytenoid
- D. Cricothyroid (Correct Answer)
Explanation: ***Cricothyroid*** - This muscle is innervated by the **external branch of the superior laryngeal nerve**, not the recurrent laryngeal nerve. [1] - Its primary function is to **tense the vocal cords**, increasing the pitch of the voice. *Thyroarytenoid* - This muscle is responsible for **relaxing the vocal cords** and closing the rima glottidis. - It receives its innervation from the **recurrent laryngeal nerve**, so it would be affected by its paralysis. [1] *Lateral cricoarytenoid* - This muscle is a primary **adductor of the vocal cords**, closing the rima glottidis. - Its innervation is derived from the **recurrent laryngeal nerve**, making it susceptible to paralysis. [1] *Vocalis* - The vocalis muscle is an intrinsic laryngeal muscle that **adjusts the tension within the vocal folds** and is considered part of the thyroarytenoid muscle. - It is innervated by the **recurrent laryngeal nerve**, and its paralysis would impair vocal fold tension. [1]
Question 8: Which part of the larynx is most commonly involved in tuberculosis (TB)?
- A. Anterior
- B. Posterior (Correct Answer)
- C. Middle
- D. Anywhere
Explanation: ***Posterior*** - The **posterior larynx**, specifically the **arytenoids** and **interarytenoid area**, is the most common site for tuberculosis involvement. - This region is susceptible due to its rich **lymphatic supply** and direct exposure to infected secretions from the lungs. *Anterior* - While TB can affect any part of the larynx, the **anterior laryngeal structures** are less frequently the primary site of involvement. - The vocal cords, which are in the anterior-middle aspect, are less commonly affected initially compared to the posterior structures. *Middle* - The middle part of the larynx, including the **vocal cords**, is not the predominant site for initial tuberculous lesions. - Involvement here often occurs as the disease progresses from more commonly affected areas. *Anywhere* - Although TB can theoretically affect any part of the larynx, it demonstrates a strong predilection for the **posterior laryngeal region**. - Stating "anywhere" does not accurately reflect the statistically significant preference for specific anatomical sites.
Question 9: Which of the following statements about laryngomalacia is true?
- A. It is characterized by an omega-shaped epiglottis.
- B. It requires immediate surgical intervention.
- C. It always requires surgical intervention in newborns.
- D. It typically presents with inspiratory stridor. (Correct Answer)
Explanation: ***It typically presents with inspiratory stridor.*** - **Laryngomalacia** is the most common cause of **inspiratory stridor** in infants, usually presenting within the first few weeks of life due to collapse of supraglottic structures during inspiration. - The stridor is characteristically **worse when crying, feeding, or lying supine**, and often improves when the infant is prone. *It is characterized by an omega-shaped epiglottis.* - While an **omega-shaped epiglottis** can be a feature seen in laryngomalacia, it is not the sole or defining characteristic and is not universally present. - The primary characteristic is the **collapse of the supraglottic structures** (arytenoids, aryepiglottic folds, and epiglottis) into the laryngeal inlet upon inspiration. *It requires immediate surgical intervention.* - The vast majority of **laryngomalacia cases are mild to moderate** and resolve spontaneously by 12-18 months of age, requiring only conservative management. - **Surgical intervention** (supraglottoplasty) is reserved for severe cases with significant feeding difficulties, failure to thrive, severe airway obstruction, or apneic episodes. *It always requires surgical intervention in newborns.* - As mentioned, **most cases are self-limiting** and do not require surgery, especially in newborns. - Surgical intervention is only considered when there are **severe symptoms** impacting the infant's health and development.
Question 10: Omega shaped epiglottis is typically seen in which of the following conditions?
- A. Epiglottitis
- B. Laryngomalacia (Correct Answer)
- C. Carcinoma of the epiglottis
- D. Tuberculosis
Explanation: **Explanation:** **Laryngomalacia** is the most common congenital anomaly of the larynx and the leading cause of stridor in infants. It is characterized by an inward collapse of the supraglottic structures during inspiration due to abnormal flaccidity. The classic endoscopic finding is an **"Omega-shaped" (Ω) epiglottis**, caused by the lateral folds of the epiglottis curling inwards. This is often accompanied by shortened aryepiglottic folds and redundant mucosa over the arytenoids. **Analysis of Incorrect Options:** * **A. Epiglottitis:** This is an acute bacterial infection (usually *H. influenzae*). On lateral X-ray, it presents with the **"Thumb sign"** due to massive inflammatory edema of the epiglottis, rather than a structural malformation. * **C. Carcinoma of the epiglottis:** Malignancy typically presents as an exophytic mass, ulceration, or irregular thickening. It destroys the normal architecture rather than shaping it into an omega form. * **D. Tuberculosis:** Laryngeal TB often involves the posterior commissure. When it affects the epiglottis, it typically causes a **"Turban epiglottis"** due to pseudo-edematous swelling and ulceration. **Clinical Pearls for NEET-PG:** * **Symptom:** Inspiratory stridor that worsens when the infant is supine, crying, or feeding, and improves when prone. * **Diagnosis:** Flexible fiberoptic laryngoscopy is the gold standard. * **Management:** Most cases (90%) are self-limiting and resolve by 18–24 months. Severe cases (respiratory distress/failure to thrive) require **supraglottoplasty**. * **Key Sign:** Omega-shaped epiglottis is the "hallmark" buzzword for this condition.
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