Neck Practice Questions

Q: Vertebral arteries are derived from?

Subclavian artery. 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.

Q: The left recurrent laryngeal nerve recurs around which structure?

Ductus arteriosus. ### 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].

Q: C cells are present in which gland?

Thyroid gland. 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**.

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

Posterior cricoarytenoid. ### 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.

Q: Which gland is enclosed by the pretracheal fascia?

Thyroid gland. 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].

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

2nd, 3rd, and 4th cervical nerves. 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).

Q: Which muscle is considered the safety muscle of the larynx?

Posterior cricoarytenoid. ### 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].

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

Occipital artery. 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.

Question 1

Vertebral arteries are derived from?

Accepted Answer

Subclavian artery

Answer

Axillary artery

Answer

Internal carotid artery

Answer

None of the above

Question 2

The left recurrent laryngeal nerve recurs around which structure?

Accepted Answer

Ductus arteriosus

Answer

Left primary bronchus

Answer

Left subclavian artery

Answer

Left subclavian vein

Question 3

The thyroid is supplied by which of the following?

Accepted Answer

All of the above.

Answer

Superior thyroid artery.

Answer

Middle thyroid artery.

Answer

Inferior thyroid artery.

Question 4

C cells are present in which gland?

Accepted Answer

Thyroid gland

Answer

Parathyroid gland

Answer

Pituitary gland

Answer

Thymus

Question 5

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

Accepted Answer

Posterior cricoarytenoid

Answer

Interarytenoid

Answer

Lateral cricothyroid

Answer

Cricothyroid

Question 6

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

Accepted Answer

The sympathetic chain runs vertically through the carotid sheath.

Answer

The carotid sheath contains the internal carotid artery, internal jugular vein, and vagus nerve.

Answer

It is formed by the investing layer of deep cervical fascia, pretracheal fascia, and prevertebral fascia.

Answer

Cranial nerves IX, XI, and XII pierce the upper part of the carotid sheath.

Question 7

Which gland is enclosed by the pretracheal fascia?

Accepted Answer

Thyroid gland

Answer

Parotid gland

Answer

Submandibular gland

Answer

Sublingual gland

Question 8

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

Accepted Answer

2nd, 3rd, and 4th cervical nerves

Answer

1st, 2nd, and 3rd cervical nerves

Answer

3rd, 4th, and 5th cervical nerves

Answer

All of the above

Question 9

Which muscle is considered the safety muscle of the larynx?

Accepted Answer

Posterior cricoarytenoid

Answer

Lateral cricoarytenoid

Answer

Transverse arytenoid

Answer

Cricothyroids

Question 10

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

Accepted Answer

Occipital artery

Answer

Suprascapular artery

Answer

Third part of the subclavian artery

Answer

External jugular vein

Neck — MCQs

Neck — MCQs

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