Neck Practice Questions

Q: A 55-year-old woman presents with a neck swelling. Imaging reveals a benign thyroid tumor. Three days after thyroidectomy, CT of her brain shows air bubbles. What is the most likely cause of these air bubbles?

Injury to the superior and middle thyroid veins. ### Explanation The presence of air bubbles in the brain (cerebral air embolism) following thyroid surgery is a rare but serious complication caused by the entry of atmospheric air into the venous system. **Why Option D is Correct:** The **Superior and Middle Thyroid Veins** drain directly into the **Internal Jugular Vein (IJV)**. During thyroidectomy, if these veins are injured or left unligated, the negative intrathoracic pressure generated during inspiration can "suck" atmospheric air into the venous lumen [1]. This air travels from the IJV to the Brachiocephalic vein, into the Right Atrium, and then to the Right Ventricle. From there, it can reach the brain via two primary routes: 1. **Paradoxical Embolism:** Crossing from the right to the left heart via a Patent Foramen Ovale (PFO). 2. **Retrograde Flow:** If the patient is in a head-up position, air can travel retrogradely up the IJV against venous flow. **Why Other Options are Incorrect:** * **Options A, B, & C (Arterial Injury):** The thyroid arteries (Superior and Inferior) are high-pressure systems. Injury to an artery results in significant hemorrhage (bleeding out) rather than air being sucked in. Air embolism is almost exclusively a venous phenomenon in this clinical context. While Option C mentions the superior thyroid vein, it is paired with an artery, making it less likely than the purely venous injury described in Option D. **NEET-PG High-Yield Pearls:** * **Venous Drainage of Thyroid:** * *Superior & Middle Thyroid Veins:* Drain into the **Internal Jugular Vein**. * *Inferior Thyroid Vein:* Drains into the **Left Brachiocephalic Vein**. * **Clinical Sign:** A "mill-wheel murmur" (splashing sound) may be heard over the precordium during a significant air embolism. * **Management:** Place the patient in the **Durant’s maneuver** (Left lateral decubitus and Trendelenburg position) to trap air in the right ventricular apex.

Q: An angiographic study of the distal part of the circle of Willis requires access to the vertebral artery. Access to this artery can be obtained via which anatomical region?

Suboccipital triangle. The vertebral artery is divided into four segments (V1–V4). The third segment (V3) is the portion that lies within the suboccipital triangle. After emerging from the foramen transversarium of the atlas (C1), the artery winds backward around the lateral mass of the atlas and lies in a groove on the upper surface of its posterior arch. This specific location within the suboccipital triangle makes it surgically and radiographically accessible before it pierces the posterior atlanto-occipital membrane to enter the skull. Analysis of Options: * Suboccipital triangle (Correct): Contains the V3 segment of the vertebral artery and the suboccipital nerve (dorsal ramus of C1). It is bounded by the Rectus capitis posterior major, Obliquus superior, and Obliquus inferior muscles. * Anterior triangle: Contains the carotid sheath (common carotid, internal jugular vein, and vagus nerve), but the vertebral artery lies deeper, protected by the prevertebral fascia and transverse processes. * Muscular triangle: A subdivision of the anterior triangle containing infrahyoid muscles and the thyroid gland; it does not provide access to the vertebral artery. * Posterior triangle: While the vertebral artery passes deep to this area, it is not a standard point of access compared to the suboccipital region where the artery is relatively superficial in its groove on C1. Clinical Pearls for NEET-PG: * Course: The vertebral artery typically enters the transverse foramen of the C6 vertebra (not C7). * Circle of Willis: The two vertebral arteries join at the lower border of the pons to form the Basilar artery. * Suboccipital Triangle Floor: Formed by the posterior atlanto-occipital membrane and the posterior arch of the atlas. * Vertebral Artery Insufficiency: Can be triggered by extreme rotation of the head, as the V3 segment is vulnerable to compression within this triangle.

Q: All of the following muscles are attached to the oblique line of the thyroid cartilage except?

Superior constrictor. The **oblique line** of the thyroid cartilage is a crucial anatomical landmark located on the external surface of the thyroid lamina. It serves as a site of attachment for three specific muscles. ### Why "Superior Constrictor" is the Correct Answer The **Superior constrictor** muscle does not attach to the thyroid cartilage. Instead, it originates from the pterygoid hamulus, the pterygomandibular raphe, and the posterior end of the mylohyoid line of the mandible. Its primary role is in the upper pharynx. ### Explanation of Other Options (The "TIS" Mnemonic) The three muscles attached to the oblique line can be easily remembered using the mnemonic **"TIS"**: * **T - Thyrohyoid (Option C):** This muscle originates from the oblique line and inserts into the hyoid bone. It elevates the larynx. * **I - Inferior Constrictor (Option B):** Specifically, the **thyropharyngeus** part of the inferior constrictor originates from the oblique line. It is essential for the swallowing reflex. * **S - Sternothyroid (Option D):** This muscle inserts onto the oblique line from its origin on the posterior surface of the manubrium. It acts to depress the larynx. ### NEET-PG High-Yield Pearls * **The Oblique Line Boundaries:** It extends from the superior thyroid tubercle to the inferior thyroid tubercle. * **Clinical Significance:** The oblique line marks the boundary for the **pretracheal fascia**. * **Killian’s Dehiscence:** While the thyropharyngeus (inferior constrictor) attaches to the oblique line, the cricopharyngeus attaches to the cricoid cartilage. The potential gap between these two parts is Killian’s Dehiscence, the site for **Zenker’s diverticulum**. * **Innervation:** The Thyrohyoid is unique among infrahyoid muscles as it is supplied by **C1 via the hypoglossal nerve**, whereas the others are supplied by the Ansa cervicalis.

Q: Which of the following structures move with deglutition?

All of the above. The movement of structures during deglutition (swallowing) is a high-yield concept in head and neck anatomy. The fundamental principle is that any structure **attached to or enclosed within the pretracheal fascia** will move superiorly during swallowing because the fascia is attached to the hyoid bone and the thyroid cartilage, which are elevated by the suprahyoid muscles. ### **Detailed Breakdown:** * **Thyroglossal Cyst:** This is the most classic example. Because the thyroglossal duct is intimately associated with the descent of the thyroid gland and often hooks around the **hyoid bone**, the cyst moves upward during deglutition. It is also the only midline swelling that moves with **protrusion of the tongue**. * **Subhyoid Bursa:** Located between the posterior surface of the hyoid bone and the thyrohyoid membrane, this bursa is anatomically tethered to the laryngeal skeleton. As the larynx rises during swallowing, the bursa moves with it. * **Pretracheal & Paratracheal Nodes:** These lymph nodes are located within or deep to the **pretracheal fascia**. Since the entire visceral compartment of the neck (including the trachea, esophagus, and thyroid) is enclosed by this fascia, these nodes move in unison with the trachea during deglutition. ### **Clinical Pearls for NEET-PG:** 1. **Thyroid Swellings:** All thyroid swellings (goiters, adenomas) move with deglutition because the thyroid gland is enclosed by the pretracheal fascia. 2. **Differential Diagnosis:** If a midline neck mass **moves with deglutition but NOT with tongue protrusion**, it is likely a thyroid swelling or a subhyoid bursa, rather than a thyroglossal cyst. 3. **Exceptions:** Laryngocele and submental lymph nodes typically do not move significantly with deglutition compared to the structures mentioned above.

Q: Which of the following nerves runs with the vagus nerve between the internal carotid artery and the internal jugular vein until the angle of the mandible?

Hypoglossal nerve. ### Explanation The correct answer is **B. Hypoglossal nerve (CN XII)**. **1. Why Hypoglossal Nerve is Correct:** The hypoglossal nerve exits the skull through the hypoglossal canal and descends in the neck. Initially, it lies deep to the internal carotid artery (ICA) and internal jugular vein (IJV). As it descends, it passes **between the ICA and IJV**, lying on the lateral side of the vagus nerve (CN X). At the level of the **angle of the mandible**, it hooks around the occipital artery and crosses the internal and external carotid arteries superficially to enter the submandibular region. This specific anatomical relationship—running between the major vessels alongside the vagus—is a classic anatomical landmark. **2. Why Other Options are Incorrect:** * **Accessory nerve (CN XI):** While it exits the jugular foramen with the vagus, it quickly passes backward, usually crossing **superficial** to the IJV (in 70% of cases) to reach the sternocleidomastoid muscle, rather than running between the vessels. * **Glossopharyngeal nerve (CN IX):** This nerve exits the jugular foramen and passes **forward between** the ICA and ECA, but it stays superior to the hypoglossal nerve and does not descend as far down the carotid sheath. * **Maxillary nerve (CN V2):** This is a branch of the trigeminal nerve that exits via the foramen rotundum into the pterygopalatine fossa. It does not enter the carotid sheath or the neck. **3. NEET-PG High-Yield Pearls:** * **The Carotid Sheath:** Contains the Common/Internal Carotid artery (medial), IJV (lateral), and Vagus nerve (posteriorly in the groove between them). * **The

Q: Paralysis of the recurrent laryngeal nerve does not affect the function of which laryngeal muscle?

Cricothyroid. ### Explanation The correct answer is **D. Cricothyroid**. **1. Underlying Medical Concept: Nerve Supply of the Larynx** The intrinsic muscles of the larynx are supplied by two branches of the Vagus nerve (CN X): * **Recurrent Laryngeal Nerve (RLN):** Supplies **all** intrinsic muscles of the larynx **except** the cricothyroid. * **External Laryngeal Nerve (a branch of the Superior Laryngeal Nerve):** Specifically supplies only the **Cricothyroid** muscle. The cricothyroid muscle acts as the primary tensor of the vocal cords by tilting the thyroid cartilage forward. Because it receives its motor innervation from the external laryngeal nerve, its function remains intact even if the recurrent laryngeal nerve is completely paralyzed. **2. Analysis of Incorrect Options:** * **A, B, and C (Thyroarytenoid, Lateral cricoarytenoid, and Vocalis):** These are all intrinsic laryngeal muscles located within the endolarynx. They are responsible for the relaxation (Thyroarytenoid/Vocalis) and adduction (Lateral cricoarytenoid) of the vocal folds. All three are strictly supplied by the **Recurrent Laryngeal Nerve**; therefore, their function would be lost in RLN paralysis. **3. Clinical Pearls for NEET-PG:** * **The "Safety Muscle":** The **Posterior Cricoarytenoid** is the only abductor of the vocal cords. It is supplied by the RLN. Bilateral RLN palsy leads to respiratory distress because this muscle fails to open the glottis. * **Semon’s Law:** In progressive RLN injury, abductor fibers are more susceptible and injured first compared to adductor fibers. * **Surgery Risk:** The RLN is most commonly injured during **Thyroidectomy** due to its close proximity to the inferior thyroid artery. The External Laryngeal Nerve is at risk during ligation of the superior thyroid artery.

Question 1

A 55-year-old woman presents with a neck swelling. Imaging reveals a benign thyroid tumor. Three days after thyroidectomy, CT of her brain shows air bubbles. What is the most likely cause of these air bubbles?

Accepted Answer

Injury to the superior and middle thyroid veins

Answer

Injury to the inferior thyroid artery

Answer

Injury to the inferior and superior thyroid arteries

Answer

Injury to the superior thyroid artery and vein

Question 2

Which of the following statements about the arterial supply of the thyroid gland is NOT true?

Accepted Answer

The parathyroid arteries are a branch arising post-division of the superior thyroid artery.

Answer

The superior thyroid artery is a branch of the external carotid artery.

Answer

The inferior thyroid artery is a branch of the thyrocervical trunk.

Answer

The thyroid ima artery is invariably a branch of the arch of the aorta.

Question 3

An angiographic study of the distal part of the circle of Willis requires access to the vertebral artery. Access to this artery can be obtained via which anatomical region?

Accepted Answer

Suboccipital triangle

Answer

Anterior triangle of the neck

Answer

Muscular triangle of the neck

Answer

Posterior triangle of the neck

Question 4

All of the following muscles are attached to the oblique line of the thyroid cartilage except?

Accepted Answer

Superior constrictor

Answer

Inferior constrictor

Answer

Thyrohyoid

Answer

Sternothyroid

Question 5

The fascia overlying the posterior triangle of the neck is pierced by which of the following structures?

Accepted Answer

External jugular vein

Answer

Spinal accessory nerve

Answer

Suprascapular nerve

Answer

Internal jugular vein

Question 6

Which of the following structures move with deglutition?

Accepted Answer

All of the above

Answer

Thyroglossal cyst

Answer

Subhyoid bursa

Answer

Pretracheal & Paratracheal nodes

Question 7

Which of the following nerves runs with the vagus nerve between the internal carotid artery and the internal jugular vein until the angle of the mandible?

Accepted Answer

Hypoglossal nerve

Answer

Accessory nerve

Answer

Glossopharyngeal nerve

Answer

Maxillary nerve

Question 8

Paralysis of the recurrent laryngeal nerve does not affect the function of which laryngeal muscle?

Accepted Answer

Cricothyroid

Answer

Thyroarytenoid

Answer

Lateral cricoarytenoid

Answer

Vocalis

Question 9

All of the following are true about the larynx EXCEPT?

Accepted Answer

All intrinsic muscles are supplied by the recurrent laryngeal nerve.

Answer

Cricothyroid is supplied by the external laryngeal nerve.

Answer

Posterior cricoarytenoid abduct the vocal cords.

Answer

Lymphatic drainage of the larynx is to the deep cervical nodes.

Question 10

Which of the following statements are true about the sternocleidomastoid muscle?

Accepted Answer

a, b, c, and e

Answer

b, c, d, and e

Answer

a, c, d, and e

Answer

a, b, d, and e

Neck — MCQs

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