Neck Practice Questions

Q: All of the following muscles are supplied by the pharyngeal plexus except?

Stylopharyngeus. The **pharyngeal plexus** is the primary nerve supply to the muscles of the pharynx and soft palate. It is formed by the pharyngeal branches of the Vagus nerve (CN X - motor), Glossopharyngeal nerve (CN IX - sensory), and sympathetic fibers from the superior cervical ganglion. ### Why Stylopharyngeus is the Correct Answer: The **Stylopharyngeus** is the only muscle of the pharynx derived from the **third pharyngeal arch**. Consequently, it is supplied solely by the nerve of that arch, the **Glossopharyngeal nerve (CN IX)**. It is the "lone exception" to the rule that all pharyngeal muscles are supplied by the Vagus nerve via the pharyngeal plexus. ### Analysis of Incorrect Options: * **Palatoglossus:** Although it is a muscle of the tongue, it is embryologically a muscle of the soft palate (4th arch). It is supplied by the pharyngeal plexus (CN X), unlike all other tongue muscles which are supplied by the Hypoglossal nerve (CN XII). * **Salpingopharyngeus:** This is a longitudinal muscle of the pharynx derived from the 4th arch and is supplied by the pharyngeal plexus (CN X). * **Cricopharyngeus:** This is the lower part of the inferior constrictor muscle. Like all constrictors, it is supplied by the pharyngeal plexus (CN X). It also receives additional innervation from the external laryngeal and recurrent laryngeal nerves. ### NEET-PG High-Yield Pearls: * **The "Rule of Exceptions":** * All muscles of the **Pharynx** are supplied by CN X (via plexus) *except* Stylopharyngeus (CN IX). * All muscles of the **Palate** are supplied by CN X (via plexus) *except* Tensor Veli Palatini (CN V3). * All muscles of the **Tongue** are supplied by CN XII *except* Palatoglossus (CN X). * All muscles of the **Larynx** are supplied by the Recurrent Laryngeal Nerve *except* Cricothyroid (External Laryngeal Nerve).

Q: What action does the thyroarytenoid muscle perform?

Relaxes vocal cord. The **thyroarytenoid muscle** is one of the intrinsic muscles of the larynx. To understand its action, one must look at its attachments: it originates from the inner surface of the thyroid cartilage and inserts into the arytenoid cartilage. ### Why the correct answer is right: * **Relaxation of Vocal Cords:** When the thyroarytenoid muscle contracts, it pulls the arytenoid cartilages toward the thyroid cartilage. This action **shortens and thickens** the vocal ligaments, thereby **relaxing** them. * **Vocalis Muscle:** The medial-most fibers of the thyroarytenoid are known as the *Vocalis* muscle. These fibers allow for fine-tuning of tension along the vocal folds, essential for changing the pitch and quality of the voice. ### Why the other options are wrong: * **A. Adduction of vocal cord:** While the thyroarytenoid has a minor adducting component, the **Lateral Cricoarytenoid** is the primary adductor of the vocal cords. * **B. Tenses vocal cord:** This is the function of the **Cricothyroid** muscle. It tilts the thyroid cartilage forward, increasing the distance between the thyroid and arytenoid, thus stretching (tensing) the cords. * **D. Closes inlet of larynx:** This is primarily the function of the **Aryepiglottic** and **Oblique Arytenoid** muscles, which act as a sphincter for the laryngeal inlet during swallowing. ### High-Yield NEET-PG Pearls: 1. **The "Singer’s Muscle":** The **Cricothyroid** is the only intrinsic muscle supplied by the **External Laryngeal Nerve**; all others are supplied by the Recurrent Laryngeal Nerve (RLN). 2. **The "Safety Muscle":** The **Posterior Cricoarytenoid** is the only **abductor** of the vocal cords. Paralysis of this muscle leads to airway obstruction. 3. **The "Relaxor":** Remember **T**hyroarytenoid = **T**erminate tension (Relaxation).

Q: Closure of the glottis is caused by all of the following except:

Posterior cricoarytenoid. ### Explanation The glottis is closed by the **adduction** of the vocal cords. To answer this question, one must distinguish between the intrinsic muscles of the larynx that act as adductors (closers) and the sole abductor (opener). **1. Why "Posterior Cricoarytenoid" is the correct answer:** The **Posterior Cricoarytenoid (PCA)** is the **sole abductor** of the vocal cords. It originates from the posterior surface of the cricoid lamina and inserts into the muscular process of the arytenoid cartilage. When it contracts, it rotates the arytenoids laterally, widening the rima glottidis. Therefore, it does not cause closure; it opens the glottis. **2. Why the other options are incorrect (Adductors):** * **Lateral Cricoarytenoid:** This is the primary adductor of the vocal cords. It rotates the muscular process anteriorly, bringing the vocal processes together. * **Thyroarytenoid:** This muscle shortens and thickens the vocal cords, contributing to the closure of the anterior glottis. * **Cricothyroid:** While primarily known as the "tensor" of the vocal cords (increasing pitch), it also acts as a weak adductor, helping to close the glottis. **Clinical Pearls for NEET-PG:** * **"Safety Muscle of the Larynx":** The Posterior Cricoarytenoid is called the safety muscle because it is the only muscle that keeps the airway open. * **Nerve Supply:** All intrinsic muscles of the larynx are supplied by the **Recurrent Laryngeal Nerve (RLN)**, *except* the **Cricothyroid**, which is supplied by the **External Laryngeal Nerve**. * **Bilateral RLN Palsy:** This results in the vocal cords remaining in a paramedian position because the PCA (abductor) is paralyzed, leading to acute respiratory distress/stridor.

Q: Which of the following statements regarding the hyoid bone is incorrect?

It develops from the 3rd and 4th branchial arches.. ### Explanation The hyoid bone is a unique, "U-shaped" bone that does not articulate with any other bone. To identify the incorrect statement, we must look at its embryological origins. **1. Why Option B is the Correct Answer (The Incorrect Statement):** The hyoid bone develops from the **2nd and 3rd branchial (pharyngeal) arches**, not the 4th. * **2nd Arch (Reichert’s cartilage):** Gives rise to the **lesser horns** (cornua) and the upper part of the body. * **3rd Arch:** Gives rise to the **greater horns** and the lower part of the body. * The 4th arch contributes to the laryngeal cartilages (thyroid cartilage), not the hyoid. **2. Analysis of Other Options:** * **Option A:** In a neutral position, the hyoid bone lies at the level of the **C3 vertebra**, between the mandible and the thyroid cartilage. * **Option C:** Because it is highly protected by the mandible, a **fracture of the hyoid** is rare. It occurs almost exclusively during manual strangulation or hanging, making it a critical finding in forensic medicine. * **Option D:** The **stylohyoid ligament** extends from the styloid process of the temporal bone to the **lesser horn** of the hyoid, suspending the bone. **High-Yield Clinical Pearls for NEET-PG:** * **"Floating Bone":** It is the only bone in the human body that lacks a bony articulation; it is suspended by muscles and ligaments. * **Muscle Attachments:** It serves as an anchor for suprahyoid (elevators) and infrahyoid (depressors) muscles, essential for swallowing and speech. Knowledge of embryology, such as the descent of the thyroid from the tongue base past the hyoid, is essential for understanding thyroglossal duct cysts [1]. * **Digastric Muscle:** The intermediate tendon of the digastric muscle is held to the hyoid by a fibrous pulley.

Q: Which nerve supplies the posterior belly of the digastric muscle?

Facial nerve. **Explanation:** The correct answer is **D. Facial nerve**. The nerve supply of the digastric muscle is a classic high-yield anatomy concept based on **embryological origin**. The digastric muscle consists of two bellies with different developmental backgrounds: * **Posterior Belly:** Derived from the **second pharyngeal arch**. Therefore, it is supplied by the nerve of the second arch—the **Facial nerve (CN VII)** (specifically, the digastric branch). * **Anterior Belly:** Derived from the **first pharyngeal arch**. It is supplied by the nerve of the first arch—the **Mandibular nerve (V3)** (specifically, the nerve to mylohyoid). **Analysis of Incorrect Options:** * **A. Mandibular nerve:** Supplies the *anterior* belly of the digastric and the mylohyoid muscle. * **B. Hypoglossal nerve (CN XII):** Supplies all intrinsic and extrinsic muscles of the tongue (except palatoglossus). While it passes near the digastric, it does not supply it. * **C. Accessory nerve (CN XI):** Supplies the sternocleidomastoid and trapezius muscles. **High-Yield Clinical Pearls for NEET-PG:** 1. **Stylohyoid Connection:** The posterior belly of the digastric and the stylohyoid muscle are both second-arch derivatives and are both supplied by the facial nerve. 2. **Intermediate Tendon:** The two bellies are connected by an intermediate tendon which is held to the hyoid bone by a fibrous pulley. 3. **Digastric Triangle:** The two bellies of the digastric form the superior boundaries of the submandibular (digastric) triangle, which contains the submandibular gland and facial artery.

Q: Name the paired cartilages of the larynx?

Corniculate cartilage. The larynx consists of a skeletal framework of nine cartilages: three are **unpaired** (single) and three are **paired** (six total). Understanding this classification is a high-yield topic for NEET-PG. ### Why Option C is Correct The **Corniculate cartilages** (of Santorini) are small, conical nodules situated at the apices of the arytenoid cartilages. They are part of the **paired cartilages**, which include: 1. **Arytenoid cartilages:** Pyramidal-shaped; crucial for vocal cord movement. 2. **Corniculate cartilages:** Located atop the arytenoids. 3. **Cuneiform cartilages:** Club-shaped; located within the aryepiglottic folds. ### Why Other Options are Incorrect * **A. Thyroid cartilage:** This is the largest **unpaired** cartilage. It forms the "Adam's apple" (laryngeal prominence). * **B. Cricoid cartilage:** This is an **unpaired** cartilage. It is the only complete cartilaginous ring in the respiratory tract, shaped like a signet ring. * **D. Hyoid bone:** While it provides attachment for laryngeal muscles and ligaments, the hyoid is a **bone**, not a laryngeal cartilage. ### NEET-PG High-Yield Pearls * **Unpaired Cartilages:** Thyroid, Cricoid, and Epiglottis. * **Elastic vs. Hyaline:** The Epiglottis, Corniculate, and Cuneiform cartilages are made of **elastic cartilage** (they do not calcify with age). The Thyroid, Cricoid, and most of the Arytenoid are **hyaline cartilage** (prone to ossification). * **Safety Landmark:** The cricoid cartilage is the landmark for the **Sellick maneuver** (cricoid pressure) during intubation to prevent gastric regurgitation. * **Narrowest Part:** In adults, the narrowest part of the airway is the **Rima Glottidis**; in infants, it is the **Cricoid cartilage**.

Q: Infrahyoid muscles are contained within which anatomical space?

Muscular triangle. ### Explanation **Correct Answer: A. Muscular triangle** The **muscular triangle** (also known as the inferior carotid triangle) is a subdivision of the anterior triangle of the neck. It is bounded superiorly by the hyoid bone, inferolaterally by the anterior border of the sternocleidomastoid, and superolaterally by the superior belly of the omohyoid muscle. Its primary contents are the **infrahyoid muscles** (sternohyoid, sternothyroid, thyrohyoid, and omohyoid) and the viscera of the neck, including the thyroid and parathyroid glands, larynx, and trachea. **Why the other options are incorrect:** * **Submental triangle:** This is an unpaired midline triangle bounded by the two anterior bellies of the digastric muscles and the hyoid bone. Its primary contents are the submental lymph nodes and small veins that form the anterior jugular vein. * **Anterior digastric (Submandibular) triangle:** Bounded by the anterior and posterior bellies of the digastric muscle and the lower border of the mandible. It primarily contains the submandibular gland, facial artery/vein, and the hypoglossal nerve. * **Carotid triangle:** Bounded by the posterior belly of the digastric, superior belly of the omohyoid, and the sternocleidomastoid. It is clinically significant for containing the carotid sheath (common carotid artery, internal jugular vein, and vagus nerve). **High-Yield NEET-PG Pearls:** * **Innervation:** All infrahyoid muscles are supplied by the **Ansa Cervicalis (C1-C3)**, *except* for the **thyrohyoid**, which is supplied by C1 fibers via the hypoglossal nerve. * **Function:** These muscles are often called "strap muscles" and function to depress the hyoid bone and larynx during swallowing and vocalization. * **Surgical Landmark:** The muscular triangle is the site for performing a **tracheostomy** or a **thyroidectomy**.

Q: The internal jugular vein is a continuation of which structure?

Sigmoid sinus. **Explanation:** The **Internal Jugular Vein (IJV)** is the largest vein in the neck, responsible for draining blood from the brain, face, and neck. It begins in the posterior compartment of the **jugular foramen** at the base of the skull as a direct continuation of the **sigmoid sinus**. At its origin, it features a localized dilatation known as the superior bulb. It descends within the carotid sheath and terminates by joining the subclavian vein to form the brachiocephalic vein. **Analysis of Options:** * **Sigmoid Sinus (Correct):** The sigmoid sinus receives blood from the transverse sinuses and the superior petrosal sinuses. As it exits the skull through the jugular foramen, it changes its name to the internal jugular vein. * **Common Facial Vein:** This is formed by the union of the anterior division of the retromandibular vein and the facial vein. It is a **tributary** of the IJV, not its origin. * **External Jugular Vein:** This is formed by the union of the posterior division of the retromandibular vein and the posterior auricular vein. It runs superficial to the sternocleidomastoid and drains into the subclavian vein. * **Superior Petrosal Sinus:** This sinus drains the cavernous sinus into the junction of the transverse and sigmoid sinuses; it does not continue directly as the IJV. **High-Yield Clinical Pearls for NEET-PG:** * **Surface Anatomy:** The IJV lies deep to the sternocleidomastoid muscle, along a line connecting the lobe of the ear to the sternoclavicular joint. * **Relations:** Inside the carotid sheath, the IJV lies **lateral** to the common carotid artery and the vagus nerve (CN X). * **Central Venous Pressure (CVP):** The right IJV is preferred for CVP catheterization because it lacks valves and provides a direct, straight path to the right atrium.

Question 1

All of the following muscles are supplied by the pharyngeal plexus except?

Accepted Answer

Stylopharyngeus

Answer

Palatoglossus

Answer

Salpingopharyngeus

Answer

Cricopharyngeus

Question 2

What action does the thyroarytenoid muscle perform?

Accepted Answer

Relaxes vocal cord

Answer

Adduction of vocal cord

Answer

Tenses vocal cord

Answer

Closes inlet of larynx

Question 3

Closure of the glottis is caused by all of the following except:

Accepted Answer

Posterior cricoarytenoid

Answer

Lateral cricoarytenoid

Answer

Cricothyroid

Answer

Thyroarytenoid

Question 4

All of the following are true about the digastric triangle EXCEPT:

Accepted Answer

It is bordered anteriorly by the anterior belly of the digastric muscle.

Answer

Its floor is formed by the mylohyoid muscle.

Answer

Its floor is formed by the hyoglossus muscle.

Answer

It contains the mylohyoid nerve and vessels.

Question 5

Which of the following statements regarding the hyoid bone is incorrect?

Accepted Answer

It develops from the 3rd and 4th branchial arches.

Answer

The hyoid bone is typically located at the level of the 3rd cervical vertebra.

Answer

A fracture of the hyoid bone is strongly suggestive of strangulation.

Answer

The lesser horns provide attachment to the stylohyoid ligament.

Question 6

Which nerve supplies the posterior belly of the digastric muscle?

Accepted Answer

Facial nerve

Answer

Mandibular nerve

Answer

Hypoglossal nerve

Answer

Accessory nerve

Question 7

Name the paired cartilages of the larynx?

Accepted Answer

Corniculate cartilage

Answer

Thyroid cartilage

Answer

Cricoid cartilage

Answer

Hyoid bone

Question 8

Infrahyoid muscles are contained within which anatomical space?

Accepted Answer

Muscular triangle

Answer

Submental triangle

Answer

Anterior digastric triangle

Answer

Carotid triangle

Question 9

Which of the following features about the thyroid gland is TRUE?

Accepted Answer

Normal thyroid gland weighs 12-20 grams.

Answer

The thyroid gland is poorly vascular.

Answer

The thyroid gland has a firm consistency.

Answer

Four parathyroid glands are located laterally and posteriorly to the thyroid gland.

Question 10

The internal jugular vein is a continuation of which structure?

Accepted Answer

Sigmoid sinus

Answer

Common facial vein

Answer

External jugular vein

Answer

Superior petrosal sinus

Neck — MCQs

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