Neck — MCQs

Neck Indian Medical PG Practice Questions and MCQs

Question 171: Which of the following muscles is the primary abductor of the larynx?

A. Cricothyroid muscle
B. Posterior cricoarytenoid muscle (Correct Answer)
C. Thyroarytenoid muscle
D. Lateral cricoarytenoid muscle

Explanation: ### Explanation The larynx is a complex cartilaginous structure where muscle functions are categorized by their effect on the vocal cords (folds). **Why Option B is Correct:** The **Posterior Cricoarytenoid (PCA)** muscle is the **only abductor** of the vocal folds. 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 arytenoid cartilages laterally, widening the **rima glottidis** (the space between the cords). This action is vital for respiration; hence, the PCA is often referred to as the **"safety muscle of the larynx."** **Why the Other Options are Incorrect:** * **A. Cricothyroid:** This muscle tilts the thyroid cartilage forward, **tensing and elongating** the vocal cords to increase the pitch of the voice. It is the only laryngeal muscle supplied by the External Laryngeal Nerve. * **C. Thyroarytenoid:** This muscle acts to **relax** the vocal folds. Its medial fibers (Vocalis) allow for fine-tuning of tension during phonation. * **D. Lateral cricoarytenoid:** This is the primary **adductor** of the vocal folds. It rotates the arytenoids medially to close the rima glottidis, essential for phonation and protecting the airway. **High-Yield NEET-PG Pearls:** 1. **Nerve Supply:** All intrinsic muscles of the larynx are supplied by the **Recurrent Laryngeal Nerve (RLN)**, *except* the Cricothyroid (External Laryngeal Nerve). 2. **Clinical Correlation:** Bilateral RLN injury leads to paralysis of the PCA muscles, causing the vocal cords to remain adducted in the midline. This results in acute airway obstruction and requires an emergency tracheostomy. 3. **Mnemonic:** **P**osterior **C**ricoarytenoid **P**ulls the cords apart (**A**bduction).

Question 172: Which of the following statements about the arterial supply of the thyroid gland is NOT true?

A. The superior thyroid artery is a branch of the external carotid artery.
B. The parathyroid arteries are a branch arising post-division of the superior thyroid artery. (Correct Answer)
C. The inferior thyroid artery is a branch of the thyrocervical trunk.
D. The thyroid ima artery is invariably a branch of the arch of the aorta.

Explanation: To master thyroid anatomy for NEET-PG, it is essential to understand the precise origins and relations of its vascular supply. ### **Explanation of the Correct Answer** **Option B is the incorrect statement (and thus the correct answer).** While the superior thyroid artery supplies the upper poles of the thyroid, the **inferior thyroid artery (ITA)** is the primary source of blood for both the superior and inferior parathyroid glands [1]. Approximately 80% of the time, the parathyroid glands receive their blood supply from the ITA. This is a high-yield surgical fact: during thyroidectomy, the ITA is ligated far from the gland to avoid compromising the blood supply to the parathyroids. ### **Analysis of Other Options** * **Option A:** This is **true**. The superior thyroid artery is the first anterior branch of the **external carotid artery**. It descends to the apex of the thyroid lobe in close proximity to the external laryngeal nerve [1]. * **Option C:** This is **true**. The inferior thyroid artery arises from the **thyrocervical trunk**, which is a branch of the first part of the subclavian artery. It is closely related to the recurrent laryngeal nerve [1]. * **Option D:** This is **true** (in the context of being a common anatomical variation). The **thyroid ima artery** is an accessory artery present in about 3–10% of individuals. While it most commonly arises from the **brachiocephalic trunk**, it can also arise directly from the **arch of the aorta** or the common carotid. ### **Clinical Pearls for NEET-PG** * **Nerve Relations:** The **Superior Thyroid Artery** is related to the **External Laryngeal Nerve** (injury causes loss of high-pitched voice). The **Inferior Thyroid Artery** is related to the **Recurrent Laryngeal Nerve** (injury causes hoarseness) [1]. * **Ligation Rule:** Ligate the superior artery **near** the gland (to save the nerve) and the inferior artery **away** from the gland (to save the nerve and parathyroid blood supply) [1]. * **Thyroid Ima Artery:** Its presence is a risk factor for bleeding during an emergency tracheostomy.

Question 173: An angiographic study of the distal part of the circle of Willis requires access to the vertebral artery. Access to this artery can be obtained via which anatomical region?

A. Anterior triangle of the neck
B. Muscular triangle of the neck
C. Posterior triangle of the neck
D. Suboccipital triangle (Correct Answer)

Explanation: The vertebral artery is divided into four segments (V1–V4). The third segment (V3) is the portion that lies within the suboccipital triangle. After emerging from the foramen transversarium of the atlas (C1), the artery winds backward around the lateral mass of the atlas and lies in a groove on the upper surface of its posterior arch. This specific location within the suboccipital triangle makes it surgically and radiographically accessible before it pierces the posterior atlanto-occipital membrane to enter the skull. Analysis of Options: * Suboccipital triangle (Correct): Contains the V3 segment of the vertebral artery and the suboccipital nerve (dorsal ramus of C1). It is bounded by the Rectus capitis posterior major, Obliquus superior, and Obliquus inferior muscles. * Anterior triangle: Contains the carotid sheath (common carotid, internal jugular vein, and vagus nerve), but the vertebral artery lies deeper, protected by the prevertebral fascia and transverse processes. * Muscular triangle: A subdivision of the anterior triangle containing infrahyoid muscles and the thyroid gland; it does not provide access to the vertebral artery. * Posterior triangle: While the vertebral artery passes deep to this area, it is not a standard point of access compared to the suboccipital region where the artery is relatively superficial in its groove on C1. Clinical Pearls for NEET-PG: * Course: The vertebral artery typically enters the transverse foramen of the C6 vertebra (not C7). * Circle of Willis: The two vertebral arteries join at the lower border of the pons to form the Basilar artery. * Suboccipital Triangle Floor: Formed by the posterior atlanto-occipital membrane and the posterior arch of the atlas. * Vertebral Artery Insufficiency: Can be triggered by extreme rotation of the head, as the V3 segment is vulnerable to compression within this triangle.

Question 174: In surgery of the submandibular salivary gland, which nerve is often involved?

A. Hypoglossal nerve
B. Glossopharyngeal nerve
C. Facial nerve (Correct Answer)
D. Lingual nerve

Explanation: The correct answer is the **Facial nerve**, specifically its **Marginal Mandibular branch**. During submandibular gland excision, this nerve is the most frequently injured structure because it descends below the lower border of the mandible, passing superficial to the submandibular gland and the facial artery within the investing layer of deep cervical fascia. **Why the other options are incorrect:** * **Hypoglossal nerve (CN XII):** This nerve lies deep to the submandibular gland, resting on the hyoglossus muscle. While it is at risk during deep dissection, it is protected by the mylohyoid muscle and is less commonly involved than the superficial marginal mandibular branch. * **Glossopharyngeal nerve (CN IX):** This nerve is located much higher and deeper in the oropharynx/tonsillar fossa region. It is not typically encountered during routine submandibular gland surgery. * **Lingual nerve:** This nerve is closely related to the submandibular duct (Wharton’s duct), where it "loops" under the duct. **NEET-PG High-Yield Pearls:** 1. **Hayes’ Maneuver:** To protect the marginal mandibular nerve, the incision is made 2–3 cm below the lower border of the mandible, and the distal end of the facial vein is ligated and retracted superiorly to "lift" the nerve out of the surgical field. 2. **Nerve-Duct Relationship:** The Lingual nerve crosses the submandibular duct twice (lateral to medial) and is often described as "triple-related" to the duct. 3. **Ganglion:** The submandibular ganglion (parasympathetic) "hangs" from the lingual nerve and supplies secretomotor fibers to the gland.

Question 175: Which artery supplies the cricothyroid muscle?

A. Recurrent laryngeal artery
B. External laryngeal artery (Correct Answer)
C. Internal laryngeal artery
D. Superior laryngeal artery

Explanation: ### Explanation The **cricothyroid muscle** is unique among the intrinsic muscles of the larynx because it is the only one located on the external surface and the only one supplied by the **external laryngeal nerve**. Its arterial supply follows this nerve. **1. Why the Correct Answer is Right:** The **External laryngeal artery** is a branch of the **superior thyroid artery** (which originates from the external carotid). It travels alongside the external laryngeal nerve to pierce the cricothyroid membrane or supply the muscle directly [2]. In many anatomical texts, this is also referred to as the **cricothyroid artery**. **2. Why the Other Options are Wrong:** * **Recurrent laryngeal artery:** This is a branch of the inferior thyroid artery. it accompanies the recurrent laryngeal nerve and supplies the internal muscles of the larynx (except the cricothyroid) [1]. * **Internal laryngeal artery:** This is a branch of the superior laryngeal artery. It accompanies the internal laryngeal nerve and pierces the thyrohyoid membrane to provide sensory supply to the supraglottis; it does not supply the external cricothyroid muscle. * **Superior laryngeal artery:** While this is the parent trunk (branch of the superior thyroid artery), it specifically pierces the thyrohyoid membrane to supply the interior of the larynx. **3. High-Yield Clinical Pearls for NEET-PG:** * **The "Singer’s Muscle":** The cricothyroid muscle tilts the thyroid cartilage forward, tensing the vocal cords to raise pitch. * **Nerve-Artery Pairing:** * *Superior Laryngeal Artery* travels with the *Internal Laryngeal Nerve*. * *Cricothyroid (External Laryngeal) Artery* travels with the *External Laryngeal Nerve*. * **Surgical Risk:** During a thyroidectomy, the external laryngeal nerve and its accompanying artery are at risk when ligating the **superior thyroid artery** near the upper pole of the thyroid gland [2].

Question 176: All of the following muscles are attached to the oblique line of the thyroid cartilage except?

A. Superior constrictor (Correct Answer)
B. Inferior constrictor
C. Thyrohyoid
D. Sternothyroid

Explanation: The **oblique line** of the thyroid cartilage is a crucial anatomical landmark located on the external surface of the thyroid lamina. It serves as a site of attachment for three specific muscles. ### Why "Superior Constrictor" is the Correct Answer The **Superior constrictor** muscle does not attach to the thyroid cartilage. Instead, it originates from the pterygoid hamulus, the pterygomandibular raphe, and the posterior end of the mylohyoid line of the mandible. Its primary role is in the upper pharynx. ### Explanation of Other Options (The "TIS" Mnemonic) The three muscles attached to the oblique line can be easily remembered using the mnemonic **"TIS"**: * **T - Thyrohyoid (Option C):** This muscle originates from the oblique line and inserts into the hyoid bone. It elevates the larynx. * **I - Inferior Constrictor (Option B):** Specifically, the **thyropharyngeus** part of the inferior constrictor originates from the oblique line. It is essential for the swallowing reflex. * **S - Sternothyroid (Option D):** This muscle inserts onto the oblique line from its origin on the posterior surface of the manubrium. It acts to depress the larynx. ### NEET-PG High-Yield Pearls * **The Oblique Line Boundaries:** It extends from the superior thyroid tubercle to the inferior thyroid tubercle. * **Clinical Significance:** The oblique line marks the boundary for the **pretracheal fascia**. * **Killian’s Dehiscence:** While the thyropharyngeus (inferior constrictor) attaches to the oblique line, the cricopharyngeus attaches to the cricoid cartilage. The potential gap between these two parts is Killian’s Dehiscence, the site for **Zenker’s diverticulum**. * **Innervation:** The Thyrohyoid is unique among infrahyoid muscles as it is supplied by **C1 via the hypoglossal nerve**, whereas the others are supplied by the Ansa cervicalis.

Question 177: The fascia overlying the posterior triangle of the neck is pierced by which of the following structures?

A. Spinal accessory nerve
B. Suprascapular nerve
C. External jugular vein (Correct Answer)
D. Internal jugular vein

Explanation: The **investing layer of deep cervical fascia** forms the roof of the posterior triangle of the neck. Understanding which structures pierce this layer is a high-yield topic for NEET-PG. ### **Explanation of the Correct Answer** The **External Jugular Vein (EJV)** is the most significant structure that pierces the roof (investing fascia) of the posterior triangle. It descends from the angle of the mandible, crosses the sternocleidomastoid muscle superficially, and then pierces the fascia about 2 cm above the clavicle to drain into the subclavian vein. **Clinical Significance:** Because the vein is adherent to the margins of the fascia it pierces, if the EJV is severed at this point, the fascia prevents the vessel from collapsing. This creates a negative pressure gradient during inspiration, which can lead to a fatal **air embolism**. ### **Analysis of Incorrect Options** * **A. Spinal Accessory Nerve (CN XI):** This nerve runs **deep** to the investing fascia (within the floor or just beneath the roof) as it crosses the posterior triangle to supply the trapezius. It does not pierce the fascia to become superficial. * **B. Suprascapular Nerve:** This arises from the brachial plexus and remains deep to the prevertebral fascia and the investing fascia as it passes toward the suprascapular notch. * **C. Internal Jugular Vein:** This vein is located deep to the sternocleidomastoid muscle within the **carotid sheath**. It does not enter the posterior triangle nor pierce its fascial roof. ### **High-Yield NEET-PG Pearls** * **Structures piercing the roof of the posterior triangle:** 1. **External Jugular Vein** (Vein) 2. **Four Cutaneous Branches of the Cervical Plexus:** Lesser occipital, Great auricular, Transverse cervical, and Supraclavicular nerves. * **The "Nerve Point" of the neck (Erb’s Point):** The location along the posterior border of the sternocleidomastoid where these four nerves emerge and pierce the fascia. * **Floor of the triangle:** Formed by the prevertebral fascia covering the splenius capitis, levator scapulae, and scalene muscles.

Question 178: Which of the following is an unpaired laryngeal cartilage?

A. Cuneiform
B. Arytenoid
C. Cricoid (Correct Answer)
D. None of the above

Explanation: The larynx is composed of **nine cartilages**: three are unpaired (single) and three are paired (doubles). Understanding this classification is a high-yield topic for NEET-PG. ### **Explanation of the Correct Answer** **C. Cricoid:** This is an **unpaired** cartilage. It is the only complete cartilaginous ring encircling the airway, shaped like a "signet ring" (broad posterior lamina and narrow anterior arch). It is located at the level of the **C6 vertebra**, marking the junction between the larynx and trachea. [1] The other two unpaired cartilages are: 1. **Thyroid:** The largest, shield-shaped cartilage. 2. **Epiglottis:** A leaf-shaped fibroelastic cartilage. ### **Explanation of Incorrect Options** * **A. Cuneiform:** These are small, club-shaped **paired** cartilages located within the aryepiglottic folds. They provide support to the vocal folds. * **B. Arytenoid:** These are pyramidal **paired** cartilages that sit atop the cricoid lamina. They are crucial for speech as they serve as the attachment point for the vocal ligaments and the muscles that adduct/abduct the vocal cords. * The third pair (not listed) is the **Corniculate** cartilages, which sit on the apices of the arytenoids. ### **High-Yield Clinical Pearls for NEET-PG** * **Histology:** All laryngeal cartilages are **Hyaline** (and thus prone to calcification with age) EXCEPT for the **Epiglottis**, **Cuneiform**, and the **apex of the Arytenoid**, which are **Elastic** cartilage. * **Surgical Landmark:** The cricoid cartilage (C6) is the landmark for the beginning of the esophagus and the point where the recurrent laryngeal nerve enters the larynx. [1] * **Safety:** The **Cricothyroid membrane** (between the thyroid and cricoid) is the site for emergency cricothyroidotomy.

Question 179: Location of the piriformis fossa?

A. Nasopharynx
B. Oropharynx
C. Laryngeal part of the pharynx (Correct Answer)
D. None of the above

Explanation: The **Piriform fossa** (also known as the piriform recess or sinus) is a deep, pear-shaped mucosal depression located on either side of the laryngeal inlet. It is a vital component of the **Laryngopharynx** (the laryngeal part of the pharynx), which extends from the upper border of the epiglottis to the lower border of the cricoid cartilage (C6 level). **Why Option C is correct:** The piriform fossa is bounded medially by the aryepiglottic fold and laterally by the thyroid cartilage and thyrohyoid membrane. Since these structures form the framework of the laryngopharynx, the fossa is anatomically situated within this specific division of the pharynx. **Why other options are incorrect:** * **Nasopharynx (A):** This is the uppermost part of the pharynx, located behind the nasal cavity. Key structures here include the pharyngeal tonsils (adenoids) and the opening of the Eustachian tube. * **Oropharynx (B):** This lies between the soft palate and the epiglottis. It contains the palatine tonsils and the vallecula, but not the piriform fossa. **Clinical Pearls for NEET-PG:** 1. **Foreign Bodies:** The piriform fossa is a common site for the lodgement of swallowed foreign bodies (e.g., fish bones). 2. **Nerve Supply:** The **Internal Laryngeal Nerve** (a branch of the Superior Laryngeal Nerve) lies just beneath the mucous membrane of the fossa. This nerve provides sensory supply to the larynx above the vocal cords. 3. **Clinical Significance:** Injury to the internal laryngeal nerve during the removal of a foreign body from the piriform fossa can lead to anesthesia of the laryngeal supraglottis, increasing the risk of aspiration. 4. **Cancer:** It is a "hidden" site for hypopharyngeal carcinomas, which may remain asymptomatic until advanced.

Question 180: Which of the following structures move with deglutition?

A. Thyroglossal cyst
B. Subhyoid bursa
C. Pretracheal & Paratracheal nodes
D. All of the above (Correct Answer)

Explanation: The movement of structures during deglutition (swallowing) is a high-yield concept in head and neck anatomy. The fundamental principle is that any structure **attached to or enclosed within the pretracheal fascia** will move superiorly during swallowing because the fascia is attached to the hyoid bone and the thyroid cartilage, which are elevated by the suprahyoid muscles. ### **Detailed Breakdown:** * **Thyroglossal Cyst:** This is the most classic example. Because the thyroglossal duct is intimately associated with the descent of the thyroid gland and often hooks around the **hyoid bone**, the cyst moves upward during deglutition. It is also the only midline swelling that moves with **protrusion of the tongue**. * **Subhyoid Bursa:** Located between the posterior surface of the hyoid bone and the thyrohyoid membrane, this bursa is anatomically tethered to the laryngeal skeleton. As the larynx rises during swallowing, the bursa moves with it. * **Pretracheal & Paratracheal Nodes:** These lymph nodes are located within or deep to the **pretracheal fascia**. Since the entire visceral compartment of the neck (including the trachea, esophagus, and thyroid) is enclosed by this fascia, these nodes move in unison with the trachea during deglutition. ### **Clinical Pearls for NEET-PG:** 1. **Thyroid Swellings:** All thyroid swellings (goiters, adenomas) move with deglutition because the thyroid gland is enclosed by the pretracheal fascia. 2. **Differential Diagnosis:** If a midline neck mass **moves with deglutition but NOT with tongue protrusion**, it is likely a thyroid swelling or a subhyoid bursa, rather than a thyroglossal cyst. 3. **Exceptions:** Laryngocele and submental lymph nodes typically do not move significantly with deglutition compared to the structures mentioned above.

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Lymphatic Drainage

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