Neck — MCQs

A 67-year-old female presents with severe neck swelling. An MRI reveals an abscess in the middle of the posterior cervical triangle of the right side, which is surgically removed. Postoperatively, she experiences shoulder drooping and difficulty raising her right hand above her head. Which nerve has most likely been iatrogenically injured?

Neck Indian Medical PG Practice Questions and MCQs

Question 121: Which laryngeal muscle is most responsible for stretching (elongating) the vocal ligament?

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

Explanation: **Explanation:** The **Cricothyroid muscle** is the primary tensor of the vocal folds. It acts by tilting the thyroid cartilage forward or pulling the cricoid cartilage upward (depending on which is fixed). This action increases the distance between the thyroid angle and the arytenoid cartilages, thereby **stretching and elongating the vocal ligaments**. This increases the tension of the vocal folds, resulting in a higher pitch of the voice. **Analysis of Incorrect Options:** * **Posterior cricoarytenoid:** This is the only **abductor** of the vocal folds (opens the glottis). It is known as the "safety muscle of the larynx." * **Lateral cricoarytenoid:** This is a major **adductor** of the vocal folds (closes the glottis), used during whispering and phonation. * **Thyroarytenoid:** This muscle acts as a **relaxor** of the vocal folds. It pulls the arytenoid cartilages toward the thyroid, shortening and thickening the vocal folds to lower the pitch. (Note: Its medial fibers, the *Vocalis*, allow for fine-tuning of tension). **High-Yield Clinical Pearls for NEET-PG:** 1. **Nerve Supply:** The Cricothyroid is the **only** laryngeal muscle supplied by the **External Laryngeal Nerve** (a branch of the Superior Laryngeal Nerve). All other intrinsic muscles are supplied by the Recurrent Laryngeal Nerve. 2. **Clinical Injury:** Damage to the external laryngeal nerve (often during thyroid surgery) paralyzes the cricothyroid, leading to a loss of high-pitched notes and easy vocal fatigue. 3. **Safety Muscle:** The Posterior Cricoarytenoid is the most important muscle to remember for airway patency; bilateral paralysis leads to acute respiratory distress.

Question 122: What is the narrowest part of the adult respiratory tract?

A. Trachea
B. Glottis (Correct Answer)
C. Supraglottis
D. Subglottis

Explanation: The respiratory tract varies in diameter at different levels, and identifying the narrowest point is a high-yield concept in both anatomy and anesthesia. **Why Glottis is Correct:** In **adults**, the narrowest part of the upper airway is the **Glottis** (the Rima Glottidis), which is the space between the free edges of the vocal folds. This is a fixed, non-distensible opening bounded by the vocal cords. During normal respiration, it is triangular, but it remains the point of maximum resistance and the smallest cross-sectional area in the adult respiratory tree. **Analysis of Incorrect Options:** * **Trachea:** While the trachea is a long tube, its diameter (approx. 1.5–2.5 cm) is significantly larger than the glottic opening. * **Supraglottis:** This region (including the epiglottis and false cords) is wider and more funnel-shaped than the glottis. * **Subglottis:** In **adults**, the subglottis is wider than the glottis. However, it is important to note that the subglottis (at the level of the cricoid cartilage) is the narrowest part in **infants and children** because the cricoid is the only complete cartilaginous ring. **Clinical Pearls for NEET-PG:** 1. **Age-related difference:** Adult = Glottis; Infant/Child (<8 years) = Subglottis (Cricoid cartilage). 2. **Endotracheal Intubation:** The glottis is the primary anatomical landmark and bottleneck for tube passage in adults. 3. **Foreign Body Aspiration:** Large foreign bodies often lodge at the glottis in adults due to its narrow dimensions. 4. **Shape:** The Rima Glottidis is triangular during quiet breathing and diamond-shaped during forced inspiration.

Question 123: The great auricular nerve originates from which cervical spinal nerve roots?

A. C2, C3 (Correct Answer)
B. C3, C4
C. C4, C5
D. C5, C6

Explanation: The **Great Auricular Nerve** is the largest ascending branch of the **Cervical Plexus**. It originates from the ventral rami of the **C2 and C3** spinal nerves. After emerging from the posterior border of the Sternocleidomastoid muscle (at the Nerve Point of the neck or Erb’s point), it ascends vertically across the muscle toward the parotid gland, where it divides into anterior and posterior branches to provide sensory innervation to the skin over the parotid gland, the mastoid process, and both surfaces of the auricle (pinna). **Analysis of Options:** * **Option A (C2, C3): Correct.** These roots form the cervical plexus loops that give rise to the great auricular, lesser occipital, and transverse cervical nerves. * **Option B (C3, C4): Incorrect.** While C3 and C4 contribute to the **Supraclavicular nerves**, they do not form the great auricular nerve. * **Option C & D (C4-C6): Incorrect.** These roots are primarily involved in the formation of the **Phrenic nerve** (C3-C5) and the **Brachial plexus** (C5-T1), which supply the diaphragm and upper limbs, respectively. **High-Yield Clinical Pearls for NEET-PG:** 1. **Nerve Point of the Neck (Erb’s Point):** Located at the midpoint of the posterior border of the Sternocleidomastoid. Four cutaneous nerves emerge here: Great Auricular (C2, C3), Lesser Occipital (C2), Transverse Cervical (C2, C3), and Supraclavicular (C3, C4). 2. **Parotid Surgery:** The great auricular nerve is at high risk during parotidectomy. Damage results in numbness over the earlobe and the angle of the mandible. 3. **Referred Pain:** Pain from the parotid gland (e.g., mumps or stones) can be referred to the ear via this nerve.

Question 124: A 35-year-old female is under general anesthesia. Prior to laryngeal intubation, which pair of muscles opens the rima glottidis?

A. Posterior cricoarytenoids (Correct Answer)
B. Lateral cricoarytenoids
C. Thyroarytenoids
D. Transverse arytenoids

Explanation: **Explanation:** The **rima glottidis** is the narrowest part of the laryngeal cavity, located between the vocal folds. Its opening (abduction) and closing (adduction) are critical for respiration and phonation, respectively. **Why the correct answer is right:** The **Posterior Cricoarytenoid (PCA)** muscles are the **only abductors** of the vocal folds. They originate from the posterior surface of the cricoid lamina and insert into the muscular process of the arytenoid cartilages. When they contract, they rotate the arytenoid cartilages laterally, pulling the vocal ligaments away from the midline, thereby opening the rima glottidis. This is a vital function for breathing and is the "safety muscle" of the larynx. **Why the incorrect options are wrong:** * **Lateral cricoarytenoids:** These are the primary **adductors** of the vocal folds. They rotate the arytenoids medially to close the rima glottidis. * **Thyroarytenoids:** These muscles act to **relax** the vocal folds by pulling the arytenoid cartilages toward the thyroid cartilage, shortening the folds. * **Transverse arytenoids:** Along with the oblique arytenoids, these muscles pull the two arytenoid cartilages together, closing the posterior portion of the rima glottidis (adduction). **High-Yield Clinical Pearls for NEET-PG:** * **Nerve Supply:** All intrinsic muscles of the larynx are supplied by the **Recurrent Laryngeal Nerve (RLN)**, *except* for the Cricothyroid, which is supplied by the External Laryngeal Nerve. * **The "Safety Muscle":** The Posterior Cricoarytenoid is known as the "safety muscle" because its paralysis leads to the inability to abduct the vocal folds, potentially causing airway obstruction. * **Cricothyroid Function:** It is the only muscle that **tenses** (elongates) the vocal folds, increasing the pitch of the voice.

Question 125: All of the following are contents of the posterior triangle of the neck except:

A. Spinal part of accessory nerve
B. Trunks of brachial plexus
C. Internal jugular vein (Correct Answer)
D. Transverse cervical artery

Explanation: The posterior triangle of the neck is bounded by the posterior border of the Sternocleidomastoid, the anterior border of the Trapezius, and the middle third of the clavicle. **Why Internal Jugular Vein (IJV) is the correct answer:** The **Internal Jugular Vein** is located within the **Carotid Sheath**, which lies deep to the Sternocleidomastoid muscle. Therefore, it is a content of the **Anterior Triangle** (specifically the Carotid Triangle), not the posterior triangle. The vein typically found in the posterior triangle is the **External Jugular Vein**, which pierces the investing layer of deep cervical fascia to drain into the subclavian vein. **Analysis of Incorrect Options:** * **Spinal part of accessory nerve (CN XI):** This is the most important nerve in the posterior triangle. It emerges from the posterior border of the Sternocleidomastoid and runs across the levator scapulae to supply the Trapezius. * **Trunks of brachial plexus:** The roots and trunks of the brachial plexus emerge between the Scalenus anterior and Scalenus medius muscles, both of which form the floor of the posterior triangle. * **Transverse cervical artery:** This is a branch of the thyrocervical trunk that crosses the posterior triangle to supply the Trapezius. **High-Yield Clinical Pearls for NEET-PG:** * **Nerve Point of the Neck:** Located at the midpoint of the posterior border of the Sternocleidomastoid; it is the site where four cutaneous branches of the cervical plexus (Great auricular, Lesser occipital, Transverse cervical, and Supraclavicular nerves) emerge. * **Floor of the Triangle:** Formed by (from superior to inferior): Splenius capitis, Levator scapulae, and Scalenus medius. * **Subclavian Vein:** Often used for central venous catheterization; it lies anterior to the scalenus anterior muscle in the supraclavicular part of the triangle.

Question 126: Which nerve supplies the infrahyoid muscles?

A. Vagus nerve
B. Cervical plexus (Correct Answer)
C. Brachial plexus
D. Supraclavicular nerve

Explanation: The infrahyoid muscles (Strap muscles)—comprising the **Sternohyoid, Sternothyroid, Omohyoid, and Thyrohyoid**—are primarily supplied by the **Ansa Cervicalis**, which is a loop of nerves originating from the **Cervical Plexus (C1–C3)**. ### Why the Correct Answer is Right: The Ansa Cervicalis is a key component of the cervical plexus. * The **superior root** (C1 via the hypoglossal nerve) supplies the superior belly of the omohyoid. * The **inferior root** (C2–C3) joins the superior root to form the loop, which then supplies the sternohyoid, sternothyroid, and inferior belly of the omohyoid. * *Note:* The Thyrohyoid is the only strap muscle supplied directly by **C1 fibers** traveling with the hypoglossal nerve, rather than the ansa loop itself. ### Why Other Options are Wrong: * **Vagus Nerve (CN X):** Supplies the muscles of the pharynx, larynx, and soft palate (via the recurrent and superior laryngeal nerves), but not the strap muscles. * **Brachial Plexus (C5–T1):** Supplies the upper limb and associated girdle muscles. It does not provide motor innervation to the anterior neck muscles. * **Supraclavicular Nerve:** This is a **purely sensory** branch of the cervical plexus (C3–C4) that supplies the skin over the shoulder and upper chest. ### High-Yield Facts for NEET-PG: * **Mnemonic for Strap Muscles:** "TOSS" (Thyrohyoid, Omohyoid, Sternohyoid, Sternothyroid). * **The C1 Exception:** Both the **Thyrohyoid** and the **Geniohyoid** (a suprahyoid muscle) are supplied by C1 fibers hitchhiking with the Hypoglossal nerve (CN XII). * **Clinical Significance:** During thyroid surgery, the ansa cervicalis is often used for nerve grafting to the recurrent laryngeal nerve because its sacrifice results in minimal functional deficit.

Question 127: The tooth-like structure of the C2 vertebra that forms a pivot joint with the C1 vertebra is called the odontoid process. What is its other name?

A. Ligamentum flavum
B. Dens (Correct Answer)
C. Matrix
D. Condyle

Explanation: **Explanation:** The **C2 vertebra (Axis)** is unique because it possesses a vertical, peg-like projection called the **Dens** (also known as the **Odontoid Process**). This structure serves as the pivot point around which the C1 vertebra (Atlas) rotates, forming the **median atlanto-axial joint**. This joint is a pivot-type synovial joint that allows for the "no" movement of the head. **Analysis of Options:** * **Dens (Correct):** Derived from the Latin word for "tooth," this is the anatomical synonym for the odontoid process. Embryologically, the dens represents the displaced body of the Atlas (C1) that has fused with the body of the Axis (C2). * **Ligamentum flavum:** This is a yellow elastic ligament that connects the laminae of adjacent vertebrae; it is not a bony process. * **Matrix:** In anatomy, this usually refers to the intercellular substance of a tissue (like bone or cartilage matrix) rather than a specific bony landmark. * **Condyle:** This refers to a rounded articular prominence. While the Occipital bone has condyles that articulate with C1 (atlanto-occipital joint), the specific tooth-like projection of C2 is the dens. **High-Yield NEET-PG Pearls:** 1. **Fractures:** Fractures of the dens (Odontoid fractures) are classified into three types (Anderson and D'Alonzo classification); **Type II** (at the base) is the most common and prone to non-union. 2. **Stability:** The dens is held against the anterior arch of the Atlas by the **Transverse Ligament**. Rupture of this ligament (e.g., in Rheumatoid Arthritis or Down Syndrome) can lead to atlanto-axial subluxation and spinal cord compression. 3. **Cruciate Ligament:** The transverse ligament, along with superior and inferior longitudinal bands, forms the "Cruciate Ligament of the Atlas."

Question 128: What is the nerve supply of the laryngopharynx?

A. Glossopharyngeal nerve
B. Vagus nerve
C. Both Glossopharyngeal and Vagus nerves (Correct Answer)
D. Neither Glossopharyngeal nor Vagus nerves

Explanation: ### Explanation The nerve supply of the pharynx is primarily derived from the **pharyngeal plexus**, which is located on the surface of the middle constrictor muscle. This plexus is formed by the pharyngeal branches of the **Glossopharyngeal (CN IX)** nerve, the **Vagus (CN X)** nerve, and sympathetic fibers from the superior cervical ganglion. **Why Option C is Correct:** The laryngopharynx (hypopharynx) receives both sensory and motor innervation through this dual system: 1. **Sensory Innervation:** The **Glossopharyngeal nerve (CN IX)** supplies the upper part of the pharynx (oropharynx), but the **Vagus nerve (CN X)**, specifically via the **internal laryngeal nerve**, provides the sensory supply to the mucosa of the laryngopharynx surrounding the laryngeal inlet. 2. **Motor Innervation:** All muscles of the pharynx (including those forming the laryngopharynx) are supplied by the **cranial part of the Accessory nerve (CN XI)** via the pharyngeal branch of the **Vagus nerve**, with the sole exception of the Stylopharyngeus (supplied by CN IX). **Why Other Options are Incorrect:** * **Option A & B:** These are incomplete. While both nerves contribute significantly, selecting one over the other ignores the integrated nature of the pharyngeal plexus where CN IX is primarily sensory and CN X is primarily motor (carrying CN XI fibers). * **Option D:** This is factually incorrect as these two nerves are the principal components of the pharyngeal nerve supply. **High-Yield Clinical Pearls for NEET-PG:** * **The "Rule of One":** All pharyngeal muscles are supplied by the Vagus (CN X) except **Stylopharyngeus**, which is supplied by the Glossopharyngeal (CN IX). * **Gag Reflex:** The **Glossopharyngeal nerve** forms the afferent (sensory) limb, while the **Vagus nerve** forms the efferent (motor) limb. * **Killian’s Dehiscence:** A potential gap between the thyropharyngeus and cricopharyngeus parts of the inferior constrictor (laryngopharynx), which is the site for **Zenker’s diverticulum**.

Question 129: What is the nerve supply of the laryngeal mucosa?

A. External laryngeal and recurrent laryngeal nerves
B. Internal laryngeal nerve (Correct Answer)
C. External laryngeal nerve
D. Superior laryngeal nerve

Explanation: The sensory innervation of the laryngeal mucosa is divided into two distinct zones by the **vocal folds (vocal cords)**. ### 1. Why the Internal Laryngeal Nerve is Correct The **Internal Laryngeal Nerve** (a branch of the Superior Laryngeal Nerve) is the primary sensory nerve of the larynx. It pierces the thyrohyoid membrane alongside the superior laryngeal artery to supply the laryngeal mucosa **above the level of the vocal folds**. Since it covers the majority of the supraglottic area, including the epiglottis and the laryngeal inlet, it is the most significant sensory nerve for the laryngeal mucosa. ### 2. Analysis of Incorrect Options * **External Laryngeal Nerve:** This is a purely **motor** nerve that supplies the cricothyroid muscle. It does not provide sensory innervation to the mucosa. * **Recurrent Laryngeal Nerve:** While this nerve provides sensory supply to the mucosa **below the level of the vocal folds** (infraglottic region), the question typically refers to the primary sensory supply (Internal Laryngeal) [1]. In many contexts, "laryngeal mucosa" implies the sensitive supraglottic area involved in the cough reflex. * **Superior Laryngeal Nerve:** While this is the parent nerve, it divides into internal (sensory) and external (motor) branches. In NEET-PG, the more specific branch (Internal Laryngeal) is the preferred answer. ### 3. High-Yield Clinical Pearls * **Cough Reflex:** The Internal Laryngeal Nerve mediates the afferent limb of the cough reflex. If foreign bodies enter the laryngeal vestibule, this nerve triggers the protective cough. * **Piriform Fossa:** The Internal Laryngeal Nerve lies just beneath the mucous membrane of the piriform fossa; it can be anesthetized here for awake intubations. * **Nerve Summary:** * **Sensory (Above Cords):** Internal Laryngeal Nerve. * **Sensory (Below Cords):** Recurrent Laryngeal Nerve [1]. * **Motor (Cricothyroid):** External Laryngeal Nerve. * **Motor (All other intrinsic muscles):** Recurrent Laryngeal Nerve [1].

Question 130: A 67-year-old female presents with severe neck swelling. An MRI reveals an abscess in the middle of the posterior cervical triangle of the right side, which is surgically removed. Postoperatively, she experiences shoulder drooping and difficulty raising her right hand above her head. Which nerve has most likely been iatrogenically injured?

A. Accessory (Correct Answer)
B. Ansa cervicalis
C. Facial
D. Hypoglossal

Explanation: ### Explanation **Correct Option: A. Accessory Nerve (CN XI)** The **Spinal Accessory Nerve** is the most commonly injured nerve during surgical procedures in the **posterior triangle of the neck** [1]. It follows a superficial and vulnerable course, emerging from the posterior border of the Sternocleidomastoid (SCM) muscle and crossing the posterior triangle to supply the **Trapezius**. * **Mechanism of Injury:** The Trapezius is responsible for shrugging the shoulders and assisting the Serratus Anterior in rotating the scapula to raise the arm above the horizontal (90°) plane. * **Clinical Presentation:** Injury results in **shoulder drooping**, winging of the scapula, and an inability to abduct the arm above the head [1]. **Incorrect Options:** * **B. Ansa cervicalis:** Located deep to the SCM within the carotid triangle; it supplies the infrahyoid (strap) muscles. Injury would not affect shoulder movement. * **C. Facial Nerve (CN VII):** Primarily supplies muscles of facial expression. While the cervical branch supplies the Platysma, it does not influence shoulder elevation. * **D. Hypoglossal Nerve (CN XII):** Located in the submandibular and carotid triangles; it supplies the intrinsic and extrinsic muscles of the tongue. Injury leads to tongue deviation, not shoulder weakness. **NEET-PG High-Yield Pearls:** * **Surface Anatomy:** The Accessory nerve enters the posterior triangle at the junction of the upper 1/3rd and middle 1/3rd of the posterior border of the SCM. * **The "Carefree" vs. "Careful" Zone:** The area above the accessory nerve in the posterior triangle is relatively safe, while the area below it contains the brachial plexus and is considered the "danger zone." * **Differential:** If the patient can raise the arm to 90° but not above, think **Serratus Anterior** (Long Thoracic Nerve) or **Trapezius** (Accessory Nerve). If they cannot initiate abduction, think **Supraspinatus**.

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Cervical Fascia

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Triangles of the Neck

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Deep Structures of the Neck

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Thyroid and Parathyroid Glands

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Vasculature of the Neck

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Lymphatic Drainage

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Cervical Plexus

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Root of the Neck

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Applied Anatomy and Clinical Correlations

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Surface Anatomy of the Neck

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