Neck — MCQs

Neck Indian Medical PG Practice Questions and MCQs

Question 101: Vertebral arteries are derived from?

A. Axillary artery
B. Subclavian artery (Correct Answer)
C. Internal carotid artery
D. None of the above

Explanation: The **vertebral artery** is the first and largest branch of the **subclavian artery**, typically arising from its first part (medial to the scalenus anterior muscle). It plays a crucial role in the posterior circulation of the brain. **Why the Subclavian Artery is correct:** The subclavian artery is divided into three parts by the scalenus anterior muscle. The first part gives rise to three branches: the vertebral artery, the internal thoracic artery, and the thyrocervical trunk. The vertebral artery ascends through the foramina transversaria of the C1–C6 vertebrae before entering the cranium via the foramen magnum to form the basilar artery. **Why the other options are incorrect:** * **Axillary Artery:** This is the continuation of the subclavian artery beyond the outer border of the first rib. Its branches supply the axilla, chest wall, and shoulder, but not the brain or spinal cord. * **Internal Carotid Artery:** This artery arises from the common carotid artery at the level of the upper border of the thyroid cartilage (C4). It provides the anterior circulation of the brain (Circle of Willis) but does not give rise to the vertebral arteries. **High-Yield Clinical Pearls for NEET-PG:** * **Segments:** The vertebral artery is divided into four segments (V1 to V4). The V3 segment lies in the **suboccipital triangle**. * **Subclavian Steal Syndrome:** Occurs when there is a proximal stenosis of the subclavian artery, causing retrograde flow in the vertebral artery to supply the arm, leading to neurological symptoms. * **Vertebral Level:** Note that the vertebral artery enters the transverse foramen of the **C6 vertebra**, skipping C7, even though C7 has a foramen transversum.

Question 102: The left recurrent laryngeal nerve recurs around which structure?

A. Left primary bronchus
B. Left subclavian artery
C. Left subclavian vein
D. Ductus arteriosus (Correct Answer)

Explanation: ### Explanation The recurrent laryngeal nerves (RLN) are branches of the Vagus nerve (CN X) that supply most of the intrinsic muscles of the larynx. Their course is asymmetrical due to the embryological development of the aortic arches. [1] **Why Ductus Arteriosus is Correct:** On the left side, the RLN hooks around the **arch of the aorta**, specifically just lateral to the **ligamentum arteriosum** (the fibrous remnant of the **ductus arteriosus**) [1]. During development, the left 6th aortic arch artery persists as the ductus arteriosus; as the heart descends, the nerve is "caught" by this structure, forcing it to recur inferior to it. **Analysis of Incorrect Options:** * **Left Primary Bronchus:** While the nerve passes posterior to the root of the lung, it does not recur (loop) around the bronchus. * **Left Subclavian Artery:** This is where the **Right** recurrent laryngeal nerve loops [2]. The right nerve recurs around the right subclavian artery (derived from the 4th aortic arch). * **Left Subclavian Vein:** The RLN passes deep to the venous structures in the neck/thorax but does not use them as a point of recurrence. **High-Yield Clinical Pearls for NEET-PG:** * **Ortner’s Syndrome:** Left RLN palsy caused by mechanical compression from a dilated left atrium (e.g., Mitral Stenosis) or an aortic aneurysm. * **Surgery Risk:** The RLNs are at high risk during **thyroidectomy** as they lie in the tracheoesophageal groove, closely related to the inferior thyroid artery [1]. * **Nerve Supply:** It supplies all intrinsic muscles of the larynx **except the cricothyroid** (supplied by the external laryngeal nerve). * **Symmetry:** The right RLN is found in the neck, whereas the left RLN begins its recurrence in the superior mediastinum [1].

Question 103: The thyroid is supplied by which of the following?

A. Superior thyroid artery.
B. Middle thyroid artery.
C. Inferior thyroid artery.
D. All of the above. (Correct Answer)

Explanation: The thyroid gland is a highly vascular endocrine organ [3]. Its arterial supply is derived from multiple sources to ensure adequate perfusion for hormone synthesis and transport. ### **Explanation of the Correct Answer** The thyroid gland is primarily supplied by the **Superior Thyroid Artery (STA)** and the **Inferior Thyroid Artery (ITA)** [2]. Additionally, in approximately 3–10% of individuals, an accessory artery called the **Thyroid Ima Artery** may be present. * **Superior Thyroid Artery (Option A):** The first branch of the **External Carotid Artery**. It descends to the upper pole of the gland and is closely related to the **External Laryngeal Nerve**. * **Inferior Thyroid Artery (Option C):** A branch of the **Thyrocervical Trunk** (from the Subclavian Artery) [2]. It supplies the posterior and inferior aspects of the gland and is closely related to the **Recurrent Laryngeal Nerve** [1]. * **Middle Thyroid Artery (Option B):** While not a standard anatomical term in many textbooks, in the context of NEET-PG and classical surgical anatomy, "Middle Thyroid Artery" is sometimes used to refer to accessory branches or the **Thyroid Ima Artery** (which arises from the Brachiocephalic trunk or Aortic arch). Since both STA and ITA are definitely correct, "All of the above" is the most appropriate choice in a multiple-choice format. ### **Clinical Pearls for NEET-PG** 1. **Nerve Relations (High Yield):** * During thyroidectomy, the **Superior Thyroid Artery** is ligated **close to the gland** to avoid injuring the External Laryngeal Nerve (which supplies the Cricothyroid muscle). * The **Inferior Thyroid Artery** is ligated **away from the gland** to avoid injuring the Recurrent Laryngeal Nerve [1]. 2. **Venous Drainage:** Unlike the arteries, there are three distinct pairs of veins: Superior and Middle (drain into Internal Jugular Vein) and Inferior (drains into Left Brachiocephalic Vein). 3. **Thyroid Ima Artery:** If present, it can cause profuse bleeding during a tracheostomy if not identified.

Question 104: C cells are present in which gland?

A. Thyroid gland (Correct Answer)
B. Parathyroid gland
C. Pituitary gland
D. Thymus

Explanation: C cells, also known as **Parafollicular cells**, are neuroendocrine cells located within the connective tissue between the thyroid follicles or embedded in the follicular lining. Their primary function is to secrete **Calcitonin**, a hormone that lowers blood calcium levels by inhibiting osteoclast activity and increasing renal calcium excretion [1]. **2. Why Other Options are Incorrect:** * **Parathyroid Gland:** This gland contains **Chief cells** (which secrete Parathyroid Hormone/PTH) and **Oxyphil cells** [2]. PTH is the functional antagonist to Calcitonin. * **Pituitary Gland:** The anterior lobe contains acidophils (Somatotropes, Lactotropes) and basophils (Corticotropes, Thyrotropes, Gonadotropes), while the posterior lobe contains pituicytes and axonal terminals. * **Thymus:** This lymphoid organ contains T-lymphocytes (thymocytes) and **Hassall’s corpuscles** (epithelial reticular cells), but no C cells. **3. High-Yield Clinical Pearls for NEET-PG:** * **Embryology:** C cells are derived from the **Ultimobranchial body** (ventral wing of the 4th/5th pharyngeal pouch), which originates from the **Neural Crest**. * **Tumor Marker:** C cells are the cells of origin for **Medullary Carcinoma of the Thyroid (MTC)**. Serum Calcitonin levels are used as a specific tumor marker for diagnosis and follow-up [3]. * **MEN Syndrome:** Medullary thyroid carcinoma is a key component of **MEN 2A and 2B** syndromes [3]. * **Staining:** C cells can be identified using immunohistochemistry for **Chromogranin** or **Calcitonin**.

Question 105: Which one of the following muscles functions as a tensor of the vocal cords during phonation?

A. Posterior cricoarytenoid (Correct Answer)
B. Interarytenoid
C. Lateral cricothyroid
D. Cricothyroid

Explanation: ### Explanation The correct answer is **D. Cricothyroid**. *(Note: There appears to be a discrepancy in the provided key. While the prompt marks Option A as correct, in standard anatomical teaching, the **Cricothyroid** is the primary tensor of the vocal cords, whereas the **Posterior Cricoarytenoid** is the sole abductor.)* #### Why Cricothyroid is the Tensor: The **Cricothyroid muscle** is the only intrinsic laryngeal muscle located on the external surface of the larynx. When it contracts, it tilts the thyroid cartilage forward or elevates the cricoid arch. This action increases the distance between the thyroid angle and the arytenoid cartilages, thereby **lengthening and tensing** the vocal cords to raise the pitch of the voice. #### Analysis of Other Options: * **Posterior Cricoarytenoid:** This is the **sole abductor** of the vocal cords (opens the glottis). It is often called the "safety muscle of the larynx" because its paralysis leads to airway obstruction. * **Interarytenoid (Transverse & Oblique):** These muscles act as **adductors** by pulling the arytenoid cartilages together, closing the posterior part of the rima glottidis. * **Lateral Cricoarytenoid:** This is the primary **adductor** of the vocal cords, pulling the muscular processes of the arytenoids forward and rotating the vocal processes medially. #### NEET-PG High-Yield Clinical Pearls: 1. **Nerve Supply Rule:** 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**. 2. **The "Safety Muscle":** The Posterior Cricoarytenoid is the only muscle that opens the airway. Bilateral RLN injury results in the cords remaining adducted, causing life-threatening stridor. 3. **Vocalis Muscle:** A part of the thyroarytenoid, it is responsible for **fine-tuning** tension (relaxing the cords) during speech.

Question 106: All of the following are true regarding the carotid sheath, except one?

A. The carotid sheath contains the internal carotid artery, internal jugular vein, and vagus nerve.
B. It is formed by the investing layer of deep cervical fascia, pretracheal fascia, and prevertebral fascia.
C. The sympathetic chain runs vertically through the carotid sheath. (Correct Answer)
D. Cranial nerves IX, XI, and XII pierce the upper part of the carotid sheath.

Explanation: ### Explanation **Why Option C is the Correct (False) Statement:** The **sympathetic chain** does not run *inside* the carotid sheath. Instead, it is located **posterior** to the sheath, embedded in the prevertebral fascia. This is a classic "trap" question in NEET-PG; while the vagus nerve is inside the sheath (posteriorly between the vessels), the sympathetic trunk is outside it. **Analysis of Other Options:** * **Option A:** This is correct. The sheath contains the **Common/Internal Carotid Artery** (medial), the **Internal Jugular Vein (IJV)** (lateral), and the **Vagus Nerve** (posteriorly in the groove between them). * **Option B:** This is correct. The carotid sheath is a condensation of all three layers of deep cervical fascia: the **investing layer**, **pretracheal fascia**, and **prevertebral fascia**. * **Option D:** This is correct. In the upper part of the neck (near the skull base), the **Glossopharyngeal (IX), Accessory (XI), and Hypoglossal (XII)** nerves pierce the sheath to reach their respective destinations. **High-Yield Clinical Pearls for NEET-PG:** * **Ansa Cervicalis:** The superior root of the ansa cervicalis (C1) travels with the hypoglossal nerve and then lies on the **anterior wall** of the carotid sheath. * **Thickness:** The sheath is thickest over the arteries and thinnest over the IJV to allow for venous expansion during increased venous return. * **Infection Spread:** The carotid sheath acts as a conduit; infections from the head can potentially track down into the **mediastinum** through this space. * **Mnemonic for Contents:** "I See **10** **C**ars in the **I**JV" (IJV, CN **10**, **C**arotid artery).

Question 107: Which gland is enclosed by the pretracheal fascia?

A. Parotid gland
B. Thyroid gland (Correct Answer)
C. Submandibular gland
D. Sublingual gland

Explanation: The **pretracheal fascia** is a component of the deep cervical fascia that lies deep to the infrahyoid (strap) muscles. It splits into two layers to enclose the **thyroid gland**, forming its false capsule. This anatomical arrangement is crucial because the fascia attaches superiorly to the oblique line of the thyroid cartilage and the hyoid bone. Consequently, the thyroid gland moves upward during swallowing (deglutition), a key clinical sign used to differentiate thyroid swellings from other neck masses [1]. **Analysis of Options:** * **Thyroid Gland (Correct):** Enclosed by the visceral layer of the pretracheal fascia. This fascia also forms the **Ligament of Berry**, which anchors the thyroid to the cricoid cartilage [1]. * **Parotid Gland (Incorrect):** Enclosed by the **investing layer** of the deep cervical fascia, which splits to form the parotid sheath (parotidomasseteric fascia). * **Submandibular Gland (Incorrect):** Also enclosed by the **investing layer** of the deep cervical fascia as it splits to form the submandibular space. * **Sublingual Gland (Incorrect):** Located in the sublingual space above the mylohyoid muscle; it is covered by oral mucosa rather than a specific layer of deep cervical fascia. **High-Yield Clinical Pearls for NEET-PG:** * **Ligament of Berry:** A thickening of the pretracheal fascia connecting the thyroid to the cricoid cartilage [1]. The **recurrent laryngeal nerve** is in close proximity here [1], [2]. * **Infections:** The pretracheal fascia blends inferiorly with the fibrous pericardium in the superior mediastinum. This provides a potential pathway for the spread of infections from the neck to the heart (mediastinitis). * **Nerve at Risk:** During thyroidectomy, the external laryngeal nerve is at risk when ligating the superior thyroid artery, and the recurrent laryngeal nerve is at risk during ligation of the inferior thyroid artery [2].

Question 108: The skin of the neck is supplied by which cervical nerves?

A. 1st, 2nd, and 3rd cervical nerves
B. 2nd, 3rd, and 4th cervical nerves (Correct Answer)
C. 3rd, 4th, and 5th cervical nerves
D. All of the above

Explanation: The cutaneous innervation of the neck is derived from the **ventral rami of the C2, C3, and C4 spinal nerves** via the branches of the **cervical plexus**. ### Why Option B is Correct: The cervical plexus (formed by C1-C4) gives off four major cutaneous branches that emerge from the posterior border of the sternocleidomastoid muscle (Erb’s point) to supply the skin: 1. **Lesser Occipital Nerve (C2):** Supplies the skin of the neck and scalp posterosuperior to the auricle. 2. **Great Auricular Nerve (C2, C3):** Supplies the skin over the parotid gland, mastoid process, and both surfaces of the auricle. 3. **Transverse Cervical Nerve (C2, C3):** Supplies the skin covering the anterior cervical triangle. 4. **Supraclavicular Nerves (C3, C4):** Supply the skin over the lower neck, shoulder, and upper chest down to the level of the second rib. ### Why Other Options are Incorrect: * **Option A & D:** These include the **1st cervical nerve (C1)**. C1 is unique because it is primarily a motor nerve and **has no cutaneous distribution**. It does not contribute to the sensory supply of the skin. * **Option C:** While C3 and C4 contribute, **C5** is part of the brachial plexus and primarily supplies the upper limb, not the skin of the neck. ### High-Yield NEET-PG Pearls: * **Erb’s Point (Punctum Nervosum):** The midpoint of the posterior border of the sternocleidomastoid where all four cutaneous branches of the cervical plexus emerge. This is the site for a **Cervical Plexus Block**. * **The "C1 Exception":** Always remember that C1 (Suboccipital nerve) has no sensory dermatome. * **Diaphragm Connection:** The phrenic nerve (C3, C4, C5) also arises from this plexus; hence, irritation of the diaphragm can cause referred pain to the shoulder (C3, C4 area).

Question 109: Which muscle is considered the safety muscle of the larynx?

A. Lateral cricoarytenoid
B. Transverse arytenoid
C. Posterior cricoarytenoid (Correct Answer)
D. Cricothyroids

Explanation: ### Explanation The **Posterior Cricoarytenoid (PCA)** is known as the **"Safety Muscle of the Larynx"** because it is the **only abductor** of the vocal cords. #### 1. Why it is the Correct Answer The PCA 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, thereby **opening the rima glottidis** (abduction). This action is vital for life as it maintains a patent airway for respiration. Bilateral paralysis of this muscle leads to the vocal cords remaining in the midline (adducted position), causing acute respiratory distress and potential asphyxiation [1]. #### 2. Why the Other Options are Incorrect * **A. Lateral Cricoarytenoid:** This is the primary **adductor** of the vocal cords (closes the glottis). It acts as an antagonist to the PCA. * **B. Transverse Arytenoid:** This muscle also aids in **adduction** by pulling the two arytenoid cartilages together, closing the posterior part of the rima glottidis. * **C. Cricothyroids:** These are the **tensors** of the vocal cords. They tilt the thyroid cartilage forward, lengthening the cords to increase the pitch of the voice. Notably, this is the only laryngeal muscle supplied by the **External Laryngeal Nerve**. #### 3. High-Yield Clinical Pearls for NEET-PG * **Innervation:** All intrinsic muscles of the larynx are supplied by the **Recurrent Laryngeal Nerve (RLN)**, *except* the Cricothyroid. * **Semon’s Law:** In progressive lesions of the RLN, the abductors (PCA) are paralyzed before the adductors. * **Nerve Injury:** Bilateral RLN injury is a surgical emergency because the loss of PCA function results in a closed airway, necessitating an emergency tracheostomy [1].

Question 110: Which of the following structures is not typically found within the subclavian triangle?

A. Suprascapular artery
B. Occipital artery (Correct Answer)
C. Third part of the subclavian artery
D. External jugular vein

Explanation: The **subclavian triangle** (also known as the omoclavicular or supraclavicular triangle) is the smaller, inferior division of the posterior triangle of the neck. It is bounded superiorly by the inferior belly of the omohyoid muscle, inferiorly by the clavicle, and anteriorly by the posterior border of the sternocleidomastoid. ### Why the Occipital Artery is the Correct Answer The **occipital artery** is a branch of the external carotid artery. It is located in the **occipital triangle** (the larger, superior division of the posterior triangle), where it crosses the apex. It does not descend into the supraclavicular region, making it the correct "except" choice. ### Analysis of Incorrect Options * **Third part of the subclavian artery:** This is the most important structure in this triangle. It begins at the lateral border of the scalenus anterior and extends to the outer border of the first rib. * **External jugular vein (EJV):** The EJV pierces the deep fascia just above the clavicle within this triangle to drain into the subclavian vein. * **Suprascapular artery:** This artery (a branch of the thyrocervical trunk) traverses the lower part of the subclavian triangle, passing behind the clavicle to reach the posterior aspect of the scapula. ### NEET-PG High-Yield Pearls * **Contents of Subclavian Triangle:** 3rd part of the subclavian artery, subclavian vein (sometimes), suprascapular/transverse cervical vessels, and the trunks of the brachial plexus. * **Nerve Alert:** The **Spinal Accessory Nerve (CN XI)** is found in the *occipital triangle*, not the subclavian triangle. It disappears under the trapezius muscle. * **Clinical Landmark:** The subclavian artery pulsation can be felt in this triangle by compressing it against the first rib to control bleeding in the upper limb.

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Lymphatic Drainage

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