Neck Practice Questions

Q: Which of the following does not occur at the level of the C6 vertebra?

The trachea bifurcates.. The **C6 vertebra** is a critical anatomical landmark in the neck, representing the transition point between several respiratory and gastrointestinal structures. ### 1. Why the Correct Answer is Right **Option A: The trachea bifurcates.** The trachea begins at the lower border of the cricoid cartilage (C6) but does **not** bifurcate there. Tracheal bifurcation (the carina) occurs at the level of the **T4-T5 vertebrae** (the Sternal Angle of Louis). In a living subject in the erect position, this bifurcation can descend as low as T6 due to gravity and respiration. ### 2. Analysis of Incorrect Options (Events at C6) The following events occur at the level of the lower border of the cricoid cartilage, which corresponds to the **C6 vertebra**: * **Option B & C: The pharynx ends and the esophagus begins.** The muscular tube of the pharynx transitions into the esophagus at this level. This is also the site of the cricopharyngeal sphincter (the narrowest part of the esophagus). * **Option D: The larynx ends.** The larynx transitions into the trachea at the lower border of the C6 vertebra. ### 3. High-Yield Clinical Pearls for NEET-PG * **Palpation:** The **Carotid Tubercle** (Chassaignac’s tubercle) is the prominent anterior tubercle of the transverse process of C6. It is used as a landmark to compress the carotid artery to control bleeding. * **Middle Cervical Ganglion:** Located at the level of C6. * **Vertebral Artery:** Usually enters the foramen transversarium at the level of **C6** (not C7). * **Omohyoid:** The intermediate tendon of the omohyoid muscle crosses the carotid sheath at the level of C6.

Q: The investing layer of the deep cervical fascia encloses all except:

Axillary vessels. The **investing layer of deep cervical fascia** is the most superficial layer of the deep fascia that surrounds the neck like a collar. ### Why "Axillary Vessels" is the Correct Answer The **axillary vessels** (and the brachial plexus) are enclosed by the **prevertebral fascia**, which extends laterally from the neck into the axilla to form the **axillary sheath**. The investing layer does not contribute to this sheath; therefore, it does not enclose these vessels. ### Explanation of Incorrect Options * **A. Sternocleidomastoid and Trapezius:** The investing layer splits to enclose two major muscles: the Trapezius (posteriorly) and the Sternocleidomastoid (anteriorly). * **B. Two Salivary Glands:** It splits to enclose the **Parotid gland** and the **Submandibular gland**. The layer covering the parotid gland thickens to form the stylomandibular ligament. * **D. Two Spaces:** It splits to form two potential spaces: the **Suprasternal space (Space of Burns)** and the **Supraclavicular space**. ### High-Yield NEET-PG Pearls * **Rule of Two:** To remember the investing layer, think of the "Rule of 2": 2 muscles (SCM, Trapezius), 2 glands (Parotid, Submandibular), and 2 spaces (Suprasternal, Supraclavicular). * **Clinical Correlation:** The Suprasternal space contains the **jugular venous arch**, the sternal heads of the SCM, and some deep cervical lymph nodes. * **Fascial Continuity:** The investing layer is continuous posteriorly with the ligamentum nuchae and superiorly with the external occipital protuberance and superior nuchal line.

Q: Which is the only laryngeal muscle that is innervated bidirectionally?

Interarytenoid. ### Explanation **Correct Answer: D. Interarytenoid** **Concept:** The **Interarytenoid (transverse and oblique arytenoids)** is unique among laryngeal muscles because it is the only one to receive **bilateral (bidirectional) innervation**. It is supplied by the **Recurrent Laryngeal Nerve (RLN)** from both the right and left sides. This anatomical redundancy ensures that even if one RLN is damaged, the muscle can still function to some extent to adduct the posterior part of the vocal cords, helping to close the posterior glottis. **Analysis of Incorrect Options:** * **A. Vocalis:** This is the medial part of the thyroarytenoid muscle. It is supplied solely by the **ipsilateral RLN**. * **B. Posterior cricoarytenoid (PCA):** Known as the "safety muscle of the larynx" (the only abductor), it is supplied only by the **ipsilateral RLN**. * **C. Lateral cricoarytenoid (LCA):** An adductor of the vocal cords, it is supplied only by the **ipsilateral RLN**. **High-Yield Clinical Pearls for NEET-PG:** * **All intrinsic muscles** of the larynx are supplied by the **Recurrent Laryngeal Nerve**, **EXCEPT** the **Cricothyroid**, which is supplied by the **External Laryngeal Nerve** (a branch of the Superior Laryngeal Nerve). * **The "Safety Muscle":** Posterior cricoarytenoid (PCA) is the only muscle that opens (abducts) the vocal cords. * **Semon’s Law:** In progressive lesions of the RLN, the abductors (PCA) are paralyzed before the adductors. * **Position of Cords:** In bilateral RLN palsy, the cords assume a **median or paramedian position**, leading to severe stridor but a relatively preserved voice.

Q: The vertebral artery traverses all of the following except?

Intervertebral foramen. **Explanation:** The **vertebral artery** is a major branch of the first part of the subclavian artery. Its course is traditionally divided into four segments (V1–V4). Understanding its anatomical trajectory is crucial for identifying why it does not pass through the intervertebral foramen. * **Why Intervertebral Foramen is the Correct Answer:** The **intervertebral foramina** are openings between adjacent vertebrae that transmit **spinal nerves** and small spinal branches of vessels, but not the main trunk of the vertebral artery. The vertebral artery runs vertically through the cervical spine, lateral to the vertebral bodies, rather than entering the spinal canal through these lateral openings. **Analysis of Other Options:** * **Foramen Transversarium:** This is a hallmark of cervical vertebrae. The vertebral artery (V2 segment) enters the foramen transversarium of the **C6** vertebra and ascends through those of C5 to C1. * **Subarachnoid Space:** After piercing the posterior atlanto-occipital membrane and the dura mater (V4 segment), the artery enters the subarachnoid space. This is where it gives off the posterior inferior cerebellar artery (PICA). * **Foramen Magnum:** The V4 segment enters the cranial cavity by passing through the foramen magnum, eventually joining its counterpart to form the basilar artery at the lower border of the pons. **High-Yield NEET-PG Pearls:** 1. **Level of Entry:** The vertebral artery enters the foramen transversarium at **C6**, NOT C7 (the C7 foramen contains only the vertebral vein). 2. **Subclavian Steal Syndrome:** Occurs due to proximal subclavian artery stenosis, leading to retrograde flow in the vertebral artery. 3. **Triangle of the Vertebral Artery:** Bound by the Longus colli and Scalenus anterior muscles; the artery lies within this space (V1 segment).

Q: The laryngeal prominence is formed by which anatomical structure?

Angle of the thyroid cartilage. **Explanation:** The **laryngeal prominence** (commonly known as the "Adam’s Apple") is a subcutaneous projection in the midline of the neck. It is formed by the **angle of the thyroid cartilage**, where its two quadrilateral laminae meet anteriorly. In males, this angle is more acute (approximately 90°), making the prominence more visible and the vocal cords longer (resulting in a deeper voice). In females, the angle is more obtuse (approximately 120°), making it less prominent. **Analysis of Options:** * **Angle of the thyroid cartilage (Correct):** This is the specific point of fusion between the right and left laminae that creates the palpable protrusion. * **Anterior margin of thyroid cartilage:** While the prominence is located anteriorly, the "margin" refers to the entire vertical edge. The specific anatomical landmark for the protrusion is the angle/junction. * **Cricoid cartilage:** This is a complete ring located inferior to the thyroid cartilage (at the level of C6). It is palpable but does not form the laryngeal prominence. * **Hyoid bone:** This is a U-shaped bone located superior to the thyroid cartilage. It serves as an attachment point for muscles but does not contribute to the laryngeal prominence. **Clinical Pearls for NEET-PG:** * **Vertebral Level:** The laryngeal prominence typically corresponds to the **C4** vertebral level. * **Thyroid Notch:** Just superior to the laryngeal prominence is the "superior thyroid notch," a V-shaped indentation. * **Cricothyroid Membrane:** Located between the thyroid and cricoid cartilages; this is the site for an emergency **cricothyroidotomy**. * **Oblique Line:** Found on the external surface of the thyroid lamina; it serves as the attachment for the Sternothyroid, Thyrohyoid, and Inferior constrictor muscles (**Mnemonic: STI**).

Q: The subclavian artery is divided by which muscle?

Scaleneus anterior. The **subclavian artery** is divided into three parts based on its anatomical relationship with the **scalenus anterior** muscle. This muscle passes anterior to the artery, acting as a landmark for its division: 1. **First Part:** From the origin of the artery to the medial border of the scalenus anterior. 2. **Second Part:** Lies directly posterior (behind) the scalenus anterior. 3. **Third Part:** From the lateral border of the scalenus anterior to the outer border of the first rib (where it becomes the axillary artery). ### Explanation of Incorrect Options: * **Pectoralis minor:** This muscle divides the **axillary artery** (not the subclavian) into three parts. * **Teres minor:** This muscle forms the superior boundary of the quadrangular and triangular spaces in the axilla but does not divide the subclavian artery. * **Trapezius:** This is a superficial muscle of the back and neck; it does not have a direct topographical relationship with the division of the subclavian artery. ### High-Yield Clinical Pearls for NEET-PG: * **Branches:** Remember the mnemonic **VIT C & D** for the branches of the subclavian artery: **V**ertebral, **I**nternal thoracic, **T**hyrocervical trunk (from 1st part); **C**ostocervical trunk (from 2nd part); **D**orsal scapular (from 3rd part). * **Scalene Triangle:** The subclavian artery and the trunks of the brachial plexus pass through the scalene triangle (between scalenus anterior and medius), whereas the **subclavian vein** passes anterior to the scalenus anterior. * **Phrenic Nerve:** This nerve descends vertically on the anterior surface of the scalenus anterior muscle, separating it from the subclavian vein.

Q: A young patient had a history of fall. The physician placed his hand on the patient's chin and instructed him to rotate his head to the opposite side against resistance. The patient was unable to perform the action. Which nerve is injured in this patient?

Spinal accessory nerve. ### Explanation **Correct Option: C. Spinal accessory nerve** The clinical scenario describes a test for the **Sternocleidomastoid (SCM)** muscle. The SCM is innervated by the **Spinal Accessory Nerve (CN XI)**. * **Mechanism:** When the right SCM contracts, it tilts the head to the right but **rotates the chin to the left (opposite side)**. Therefore, the inability to rotate the head to the opposite side against resistance indicates paralysis of the SCM on the side being tested. * **Anatomy:** The Spinal Accessory Nerve (CN XI) is a purely motor nerve that supplies the SCM and the Trapezius. Injury to this nerve commonly occurs in the posterior triangle of the neck (e.g., during lymph node biopsy or trauma). **Analysis of Incorrect Options:** * **A. Posterior auricular nerve:** A branch of the Facial nerve (CN VII) that supplies the auricularis posterior muscle and the occipital belly of the occipitofrontalis. It does not assist in neck rotation. * **B. 10th cranial nerve (Vagus):** Primarily provides parasympathetic innervation to thoracic and abdominal viscera and motor supply to the pharynx and larynx. It does not supply the SCM. * **D. 12th cranial nerve (Hypoglossal):** Supplies the intrinsic and extrinsic muscles of the tongue. Injury would result in tongue deviation toward the side of the lesion, not neck weakness. **High-Yield Clinical Pearls for NEET-PG:** * **Trapezius Test:** To test the other muscle supplied by CN XI, ask the patient to **shrug their shoulders** against resistance. * **Nerve Course:** CN XI enters the skull through the Foramen Magnum and exits via the **Jugular Foramen**. * **Iatrogenic Injury:** The most common cause of CN XI injury is medical procedures in the **posterior triangle** of the neck. * **Differentiating SCM vs. Trapezius:** If only the Trapezius is affected (drooping shoulder), the nerve lesion is likely distal to the branch supplying the SCM.

Q: Which muscle causes opening of the upper end of the esophagus?

Cricopharyngeus of inferior constrictor. ### Explanation The **Cricopharyngeus** muscle is the correct answer because it functions as the **Upper Esophageal Sphincter (UES)**. **1. Why Cricopharyngeus is Correct:** The inferior constrictor muscle consists of two parts: the upper oblique fibers (**Thyropharyngeus**) and the lower horizontal fibers (**Cricopharyngeus**). Unlike other pharyngeal muscles that contract to propel food, the cricopharyngeus is **tonically contracted** at rest to prevent air from entering the esophagus and gastric contents from refluxing into the pharynx. During swallowing, this muscle **relaxes**, allowing the upper end of the esophagus to open and receive the food bolus [1]. **2. Why the other options are incorrect:** * **Epiglottis:** This is a cartilaginous structure, not a muscle. Its primary role is to flip downward to cover the laryngeal inlet during swallowing to prevent aspiration. * **Thyropharyngeus:** This is the upper part of the inferior constrictor. Its fibers are propulsive (peristaltic) in nature; it contracts to push food down rather than acting as a sphincter. * **Stylopharyngeus:** This is a longitudinal muscle of the pharynx (innervated by the Glossopharyngeal nerve). Its role is to **elevate** the larynx and pharynx during swallowing, not to open the esophageal lumen. **3. Clinical Pearls for NEET-PG:** * **Killian’s Dehiscence:** A potential gap exists between the thyropharyngeus and cricopharyngeus. This is a weak area where mucosal herniation can occur, leading to **Zenker’s Diverticulum**. * **Innervation:** While most pharyngeal muscles are supplied by the Pharyngeal Plexus (Vagus nerve), the **Stylopharyngeus** is the unique exception, supplied by the **Glossopharyngeal nerve (CN IX)**. * **Nerve Supply:** The cricopharyngeus receives motor supply from the **external laryngeal** and **recurrent laryngeal** nerves.

Q: Which muscle is an opener of the glottis?

Posterior cricoarytenoid. **Explanation:** The intrinsic muscles of the larynx are responsible for controlling the tension of the vocal cords and the size of the rima glottidis. **1. Why the Correct Answer is Right:** The **Posterior Cricoarytenoid (PCA)** 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, pulling the vocal ligaments away from the midline. This action opens the rima glottidis (glottis), allowing for inspiration. Because it is the sole muscle responsible for opening the airway, it is often referred to as the **"Safety Muscle of the Larynx."** **2. Why the Other Options are Wrong:** * **Lateral Cricoarytenoid:** This is the primary **adductor** of the vocal folds. It rotates the arytenoids medially to close the glottis (the intermembranous portion). * **Transverse & Oblique Arytenoids (Interarytenoids):** These muscles pull the two arytenoid cartilages together, closing the posterior portion of the glottis (the intercartilaginous portion). * All three incorrect options are **adductors** (closers) of the glottis, used during phonation and to protect the airway during swallowing. **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 (supplied by the External Laryngeal Nerve). * **Clinical Correlation:** Bilateral injury to the Recurrent Laryngeal Nerve results in the vocal cords being stuck in a paramedian position because the PCA (the only abductor) is paralyzed. This leads to acute respiratory distress and stridor, often requiring an emergency tracheostomy. * **Tension:** The **Cricothyroid** is the chief tensor of the vocal cords (increases pitch), while the **Thyroarytenoid** (Vocalis) relaxes them.

Q: The cricoid cartilage can be palpated at which anatomical landmark?

Thyroid cartilage. The cricoid cartilage is a complete ring of hyaline cartilage located at the level of the **C6 vertebra**. It serves as a critical landmark in head and neck anatomy. **Explanation of the Correct Answer:** The **Thyroid cartilage** is the correct landmark because the cricoid cartilage is situated immediately inferior to it [1]. In clinical practice, the cricoid is identified by first palpating the laryngeal prominence (Adam’s apple) of the thyroid cartilage and sliding the finger downwards across the **cricothyroid membrane** to feel the firm, horizontal ridge of the cricoid arch [1]. This relationship is vital for procedures like cricothyroidotomy. **Analysis of Incorrect Options:** * **First tracheal ring:** This lies immediately below the cricoid cartilage. While adjacent, it is softer and often covered by the isthmus of the thyroid gland (at the level of the 2nd to 4th tracheal rings), making it a less reliable primary landmark for identifying the cricoid. * **Cricoid cartilage:** This option is tautological; a structure cannot be its own landmark for palpation in the context of surface anatomy. * **Arteries can never be palpated:** This is factually incorrect. The carotid pulse is easily palpated lateral to the cricoid cartilage at the same vertebral level (C6). **High-Yield Clinical Pearls for NEET-PG:** * **Vertebral Level:** The cricoid cartilage marks the level of **C6**. * **Anatomical Junctions:** At the lower border of the cricoid (C6), the larynx becomes the trachea, and the pharynx becomes the esophagus. * **Middle Thyroid Vein:** This vein exits the thyroid gland at the level of the cricoid. * **Chassaignac’s Tubercle:** The carotid tubercle (anterior tubercle of C6 transverse process) lies at this level and is used to compress the carotid artery.

Question 1

Which of the following does not occur at the level of the C6 vertebra?

Accepted Answer

The trachea bifurcates.

Answer

The pharynx ends.

Answer

The esophagus begins.

Answer

The larynx ends.

Question 2

The investing layer of the deep cervical fascia encloses all except:

Accepted Answer

Axillary vessels

Answer

Sternocleidomastoid and trapezius muscles

Answer

Two salivary glands

Answer

Two spaces

Question 3

Which is the only laryngeal muscle that is innervated bidirectionally?

Accepted Answer

Interarytenoid

Answer

Vocalis

Answer

Posterior cricoarytenoid

Answer

Lateral cricoarytenoid

Question 4

The vertebral artery traverses all of the following except?

Accepted Answer

Intervertebral foramen

Answer

Foramen magnum

Answer

Subarachnoid space

Answer

Foramen transversarium

Question 5

The laryngeal prominence is formed by which anatomical structure?

Accepted Answer

Angle of the thyroid cartilage

Answer

Cricoid cartilage

Answer

Hyoid bone

Answer

Anterior margin of thyroid cartilage

Question 6

The subclavian artery is divided by which muscle?

Accepted Answer

Scaleneus anterior

Answer

Pectoralis minor

Answer

Teres minor

Answer

Trapezius

Question 7

A young patient had a history of fall. The physician placed his hand on the patient's chin and instructed him to rotate his head to the opposite side against resistance. The patient was unable to perform the action. Which nerve is injured in this patient?

Accepted Answer

Spinal accessory nerve

Answer

Posterior auricular nerve

Answer

10th cranial nerve

Answer

12th cranial nerve

Question 8

Which muscle causes opening of the upper end of the esophagus?

Accepted Answer

Cricopharyngeus of inferior constrictor

Answer

Epiglottis

Answer

Thyropharyngeus

Answer

Stylopharyngeus

Question 9

Which muscle is an opener of the glottis?

Accepted Answer

Posterior cricoarytenoid

Answer

Lateral cricoarytenoid

Answer

Transverse arytenoid

Answer

Interarytenoid

Question 10

The cricoid cartilage can be palpated at which anatomical landmark?

Accepted Answer

Thyroid cartilage

Answer

First tracheal ring

Answer

Cricoid cartilage

Answer

Arteries can never be palpated

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