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: A 58-year-old female, known case of multinodular goiter, underwent subtotal thyroidectomy. After 8 days, the patient presented with hoarseness of voice. Which of the following muscles is NOT innervated by the nerve most likely damaged during this surgery?

Cricothyroid. ***Cricothyroid*** - The **cricothyroid muscle** is innervated by the **external branch of the superior laryngeal nerve**, not the recurrent laryngeal nerve. - Post-thyroidectomy hoarseness typically indicates **recurrent laryngeal nerve (RLN) injury**, which does not affect the cricothyroid muscle. *Posterior cricoarytenoid* - This muscle is innervated by the **recurrent laryngeal nerve** and is responsible for **vocal cord abduction**. - **RLN injury** during thyroidectomy would affect this muscle, contributing to hoarseness and potential airway compromise. *Lateral cricoarytenoid* - Innervated by the **recurrent laryngeal nerve** and functions in **vocal cord adduction**. - Damage to the **RLN** would impair this muscle's function, leading to voice changes and hoarseness. *Thyroarytenoid* - This muscle is supplied by the **recurrent laryngeal nerve** and includes the **vocalis muscle** portion. - **RLN injury** would affect vocal cord tension and fine voice control, directly causing the observed hoarseness.

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 nerve is liable to get injured during the removal of a fish bone from the pyriform fossa?

Internal laryngeal nerve. **Explanation:** The **internal laryngeal nerve** is the correct answer due to its specific anatomical location relative to the pyriform fossa. **1. Why the Internal Laryngeal Nerve is correct:** The pyriform fossa is a mucosal-lined depression located on either side of the laryngeal inlet. The **internal laryngeal nerve** (a branch of the Superior Laryngeal Nerve) runs submucosally beneath the mucous membrane of the **floor of the pyriform fossa**. It pierces the thyrohyoid membrane to provide sensory innervation to the larynx above the vocal cords. Because it lies just beneath the thin mucosa, it is highly vulnerable to injury during the removal of impacted foreign bodies (like fish bones) or during the accidental penetration of the fossa by instruments. **2. Why other options are incorrect:** * **Superior Laryngeal Nerve (SLN):** This is the parent trunk. While it is related, it divides into internal and external branches before reaching the fossa. The internal branch is the specific structure at risk within the fossa itself. * **External Laryngeal Nerve:** This nerve remains outside the larynx to supply the cricothyroid muscle. It does not enter the pyriform fossa. * **Recurrent Laryngeal Nerve (RLN):** This nerve ascends in the tracheoesophageal groove and enters the larynx near the cricothyroid joint. It is not located in the floor of the pyriform fossa. **Clinical Pearls for NEET-PG:** * **Sensory Innervation:** The internal laryngeal nerve mediates the **cough reflex**. Injury leads to anesthesia of the supraglottic larynx, increasing the risk of aspiration. * **Foreign Bodies:** The pyriform fossa is the most common site for impacted fish bones in the throat. * **Nerve Block:** The internal laryngeal nerve can be intentionally blocked via the pyriform fossa using topical anesthesia for awake intubation.

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: All the structures lie behind the thoracic duct at the root of the neck, except?

Right phrenic nerve. Explanation: The thoracic duct is the largest lymphatic vessel in the body. At the root of the neck, it arches laterally at the level of the **C7 vertebra**, rising about 3–4 cm above the clavicle to drain into the junction of the left internal jugular and left subclavian veins. **1. Why "Right Phrenic Nerve" is the correct answer:** The thoracic duct is located on the **left side** of the root of the neck. Therefore, it relates to the **left phrenic nerve**, not the right. The left phrenic nerve lies posterior to the thoracic duct, separated only by the prevertebral fascia. The right phrenic nerve is anatomically distant from the course of the thoracic duct at this level. **2. Analysis of Incorrect Options (Structures lying posterior to the duct):** As the thoracic duct arches laterally from the esophagus to the venous junction, it passes **anterior** to several key structures (meaning these structures lie **behind** it): * **Vertebral artery and vein:** These lie deep in the "triangle of the vertebral artery" behind the duct. * **Medial border of Scalenus anterior:** The duct crosses in front of this muscle before reaching the venous angle. * **Thyrocervical trunk and its branches:** Specifically, the suprascapular, transverse cervical, and inferior thyroid arteries lie posterior to the duct. * **Other structures behind it:** Left sympathetic trunk and the first part of the left subclavian artery. **Clinical Pearls for NEET-PG:** * **Chylothorax:** Injury to the thoracic duct (often during esophageal surgery or central line placement) leads to the accumulation of milky lymph in the pleural cavity. * **Virchow’s Node:** The duct communicates with the supraclavicular lymph nodes; hence, gastric malignancy often metastasizes here (Troisier’s sign). * **Level of Crossing:** The duct crosses from the right to the left side of the thorax at the level of the **T5 vertebra**.

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: The recurrent laryngeal nerve supplies all laryngeal muscles except which one?

Cricothyroid. **Explanation:** The nerve supply of the larynx is a high-yield topic for NEET-PG. The intrinsic muscles of the larynx are derived from the 4th and 6th branchial arches, which determines their innervation. **1. Why Cricothyroid is the Correct Answer:** The **Cricothyroid** muscle is the only intrinsic muscle of the larynx derived from the **4th branchial arch**. Consequently, it is supplied by the **External Laryngeal Nerve** (a branch of the Superior Laryngeal Nerve). All other intrinsic muscles are derived from the 6th branchial arch and are supplied by the **Recurrent Laryngeal Nerve (RLN)**. **2. Analysis of Incorrect Options:** * **Lateral cricoarytenoid:** This is the primary adductor of the vocal cords. It is supplied by the RLN. * **Posterior cricoarytenoid:** Known as the "safety muscle of the larynx," it is the only abductor of the vocal cords. It is supplied by the RLN. * **Transverse arytenoids:** This is the only unpaired muscle of the larynx. It acts to adduct the posterior part of the glottis and is supplied by the RLN. **Clinical Pearls for NEET-PG:** * **The "Safety Muscle":** The Posterior Cricoarytenoid is the only muscle that opens (abducts) the vocal cords. Bilateral RLN palsy leads to respiratory distress because this muscle fails to function. * **The "Tensor":** The Cricothyroid muscle tenses the vocal cords. Injury to the External Laryngeal Nerve (often during thyroidectomy) results in a loss of high-pitched voice and easy vocal fatigue. * **Sensory Supply:** Above the vocal cords, sensation is carried by the **Internal Laryngeal Nerve**; below the vocal cords, it is carried by the **Recurrent Laryngeal Nerve**.

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

A 58-year-old female, known case of multinodular goiter, underwent subtotal thyroidectomy. After 8 days, the patient presented with hoarseness of voice. Which of the following muscles is NOT innervated by the nerve most likely damaged during this surgery?

Accepted Answer

Cricothyroid

Answer

Posterior cricoarytenoid

Answer

Lateral cricoarytenoid

Answer

Thyroarytenoid

Question 3

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 4

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 5

Which nerve is liable to get injured during the removal of a fish bone from the pyriform fossa?

Accepted Answer

Internal laryngeal nerve

Answer

Superior laryngeal nerve

Answer

External laryngeal nerve

Answer

Recurrent laryngeal nerve

Question 6

Which gland is enclosed by the pretracheal fascia?

Accepted Answer

Thyroid gland

Answer

Parotid gland

Answer

Submandibular gland

Answer

Sublingual gland

Question 7

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 8

All the structures lie behind the thoracic duct at the root of the neck, except?

Accepted Answer

Right phrenic nerve

Answer

Vertebral artery and vein

Answer

Medial border of the scalenus anterior

Answer

Thyrocervical trunk and its branches

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

The recurrent laryngeal nerve supplies all laryngeal muscles except which one?

Accepted Answer

Cricothyroid

Answer

Lateral cricoarytenoid

Answer

Posterior cricoarytenoid

Answer

Transverse arytenoids

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