Thorax Practice Questions

Q: A 30-year-old man came with choking episodes after ingestion of fish bone while eating. The fishbone got impacted at the level of T4 in the esophagus. Which is the most likely site of obstruction?

Arch of aorta. ***Arch of aorta*** - The esophagus has three principal anatomic constrictions where foreign bodies, such as swallowed fish bones, commonly lodge; the second constriction occurs at the level of **T4/T5** where the **arch of the aorta** passes anteriorly. - This large anatomical structure compresses the esophagus against the vertebral column, creating a localized narrowing precisely matching the T4 level described for the obstruction [1]. *Left bronchus* - The **left main bronchus** also crosses anterior to the esophagus and contributes significantly to the formation of the **middle esophageal constriction** at the T4/T5 level. - However, in standard radiological and endoscopic visualization, the compression caused by the arch of the aorta is often considered the dominant landmark at this specific location [1]. *Cricopharyngeus* - This structure forms the initial and **uppermost esophageal constriction** (upper esophageal sphincter), located at the level of the **C6 vertebra** (cervical spine). - Obstruction at the cricopharyngeus would occur in the neck, which is anatomically much higher than the reported **T4 (thoracic spine)** impaction site. *Diaphragm* - The passage of the esophagus through the **esophageal hiatus** of the diaphragm forms the **third and lowest physiological constriction**, typically located at the vertebral level of **T10**. - This site of potential foreign body obstruction is significantly distal and caudal to the T4 level described in the clinical case. Management of such objects often involves careful endoscopy under general anesthesia to prevent perforation [2].

Q: A woman presents with a breast lump, associated with skin dimpling and nipple retraction. What is the most likely anatomical structure responsible for the skin dimpling?

Suspensory (Cooper’s) ligaments. ***Suspensory (Cooper’s) ligaments*** - These are fibrous septa that run from the deep pectoral fascia to the dermis of the skin, providing structural support to the breast [1]. - Invasion and shortening of these ligaments by a growing tumor pull on the overlying skin, causing the characteristic **skin dimpling** or peau d'orange appearance [1]. *Lactiferous ducts* - These are the milk ducts that converge and open at the nipple [1]. - Malignant infiltration of the lactiferous ducts is more commonly associated with **nipple retraction** and pathologic nipple discharge, rather than skin dimpling [2]. *Pectoral fascia* - This is a deep layer of connective tissue that covers the pectoralis major muscle, on which the breast lies [1]. - Tumor invasion into the pectoral fascia can cause the breast to become **fixed** to the chest wall, a sign of advanced disease, but does not directly cause superficial skin dimpling. *Subcutaneous fat* - This tissue makes up the bulk of the breast volume and surrounds the glandular components. - Subcutaneous fat itself lacks the tensile strength to pull the skin inward; it is the **fibrous ligaments** passing through the fat that cause retraction [1].

Q: While doing an endoscopy, constriction is felt at the oesophageal junction at 25 cm from the incisor. This is due to?

b. Arch of aorta. ***b. Arch of aorta*** - The esophagus has **three normal anatomical constrictions** that are clinically important - At **25 cm from the incisors**, the esophagus is compressed by the **arch of aorta** crossing anteriorly, creating the **middle constriction** - This is the second of three constrictions and corresponds to the level of the **T4-T5 vertebrae** - These constrictions are sites where **foreign bodies may lodge** and where **strictures are more likely to develop** [1] *a. Inferior vena cava* - The IVC runs on the right side of the vertebral column and does **not cross anterior to the esophagus** - It does not cause any constriction of the esophagus *c. Right bronchus* - The **left main bronchus** (not right) crosses the esophagus anteriorly at approximately the same level as the aortic arch - The right bronchus does not come into contact with the esophagus *d. Diaphragmatic opening* - This causes the **third (lower) constriction** at approximately **40 cm from the incisors** - This is at the level of the **esophageal hiatus** in the diaphragm (T10 level) - Not at 25 cm as mentioned in the question

Q: Which of the following structures passes through the foramen marked by the arrow? ![img-53.jpeg](img-53.jpeg)

Thoracic duct. ***Thoracic duct*** - The arrow in the image points to the **aortic hiatus**, which is the most posterior of the three major openings in the diaphragm, located at the vertebral level of **T12**. - This hiatus provides passage for the **aorta**, the **thoracic duct**, and the **azygos vein** from the thorax into the abdomen. *Oesophagus* - The oesophagus passes through its own opening, the **oesophageal hiatus**, which is located more anteriorly and superiorly at the **T10** vertebral level within the muscular part of the diaphragm. - This opening is formed by the fibers of the **right crus** of the diaphragm and also transmits the **vagal trunks**. *Inferior vena cava* - The inferior vena cava traverses the diaphragm through the **caval opening**, the most anterior and superior opening, situated at the **T8** vertebral level. - This foramen is located within the **central tendon** of the diaphragm and also allows passage for branches of the **right phrenic nerve**. *Sympathetic trunk* - The sympathetic trunk does not pass through any of the major apertures but rather descends posterior to the diaphragm. - It typically passes behind the **medial arcuate ligament** or pierces the **crus of the diaphragm** to enter the abdomen.

Q: All of the following are superior mediastinal tumors except:

Parathyroid. ***Parathyroid*** - Parathyroid tumors are **not classic superior mediastinal tumors** - Ectopic parathyroid adenomas, when mediastinal, are typically located in the **anterior-inferior mediastinum**, not the superior mediastinum - They descend embryologically with the thymus from the 3rd pharyngeal pouch and are found in the **thymic tongue** or anterior mediastinum at lower levels - **Not part of the classic anterior/superior mediastinal mass differential** (the "4 Ts") *Thymus* - The thymus is the **primary organ** of the anterior and superior mediastinum - **Thymoma, thymic hyperplasia, and thymic carcinoma** are classic superior/anterior mediastinal tumors - Part of the "4 Ts" mnemonic: **Thymus**, Thyroid, Teratoma, Terrible lymphoma *Thyroid* - **Retrosternal (substernal) goiter** represents extension of cervical thyroid into the superior mediastinum - Common cause of superior mediastinal masses, especially in older patients - Can cause tracheal compression and superior vena cava syndrome - Part of the "4 Ts" of anterior mediastinal masses *Lymphoma* - **Lymphoma (especially Hodgkin lymphoma and T-cell lymphoblastic lymphoma)** is one of the most common anterior/superior mediastinal masses - Part of the "4 Ts": Thymus, Thyroid, Teratoma, and **"Terrible lymphoma"** - Typically presents as a large anterior mediastinal mass in young adults - May cause B symptoms (fever, night sweats, weight loss) and superior vena cava syndrome

Q: Match the cardiac anatomical features from Column I with their corresponding labels from Column II. Column I: 1. Receives oxygenated blood from pulmonary veins; 2. Lies anterior to ascending aorta; 3. Arises from LV; 4. Hypertrophy in pulmonary stenosis. Column II: A. Ascending aorta; B. Right ventricle; C. Pulmonary trunk; D. Left atrium.

1-D, 2-C, 3-A, 4-B. 1-D, 2-C, 3-A, 4-B - 1-D (Receives oxygenated blood): The left atrium receives four pulmonary veins carrying oxygenated blood from the lungs [1], making it the only chamber that receives oxygenated blood directly from pulmonary circulation. - 2-C (Lies anterior to ascending aorta): The pulmonary trunk is positioned anteriorly and slightly to the left of the ascending aorta as both vessels exit from the base of the heart. - 3-A (Arises from LV): The ascending aorta arises directly from the left ventricle through the aortic valve and is the major systemic artery carrying oxygenated blood to the body. - 4-B (Hypertrophy in pulmonary stenosis): Pulmonary stenosis increases resistance to right ventricular outflow, causing chronic pressure overload and subsequent right ventricular hypertrophy. 1-A, 2-B, 3-C, 4-D - This matching is incorrect because the ascending aorta (A) does not receive blood from pulmonary veins [1]; it arises from the LV and carries blood away from the heart. Additionally, the pulmonary trunk (C) arises from the right ventricle, not the left ventricle. 1-B, 2-D, 3-C, 4-A - This matching is incorrect because the right ventricle (B) receives deoxygenated blood from the right atrium via the vena cavae, not oxygenated blood from pulmonary veins [1]. The left atrium (D) is a posterior chamber and does not lie anterior to the ascending aorta. 1-C, 2-A, 3-D, 4-B - This matching is incorrect because the pulmonary trunk (C) carries deoxygenated blood to the lungs; it does not receive oxygenated blood from pulmonary veins [1]. The left atrium (D) is not a vessel that arises from the LV—the correct structure is the ascending aorta (A).

Q: Which nerve marked as X innervates the Aortic Arch?

Aortic depressor nerve. ***Aortic depressor nerve*** - The nerve marked as X in the diagram directly innervates the **aortic baroreceptors** located in the aortic arch. - This nerve is also known as the **aortic depressor nerve**, a branch of the vagus nerve (CN X), which transmits sensory information about blood pressure from the aortic arch to the central nervous system. *Carotid sinus nerve* - The carotid sinus nerve (also known as Hering's nerve) innervates the **carotid sinus and carotid body**, which are located at the bifurcation of the common carotid artery. - This nerve transmits sensory information from the carotid baroreceptors and chemoreceptors, distinct from the aortic arch. *Inferior cervical cardiac nerve* - The inferior cervical cardiac nerve is a **sympathetic nerve** that originates from the inferior cervical ganglion and innervates the heart. - It does not primarily innervate the aortic arch baroreceptors; its function is related to cardiac rate and contractility. *Superior cervical cardiac nerve* - Similar to the inferior cervical cardiac nerve, the superior cervical cardiac nerve is a **sympathetic nerve** originating from the superior cervical ganglion. - It primarily contributes to the cardiac plexus and innervates the heart, not specifically the aortic arch baroreceptors.

Q: Identify the tract shown as X which is responsible for conduction from SA node to AV node.

Tract of Thorel. **Tract of Thorel** - The image shows three internodal tracts (anterior, middle, posterior) connecting the **SA node** to the **AV node**. Tract X specifically points to the **posterior internodal tract**. - The posterior internodal tract is also known as the **Tract of Thorel**, which conducts impulses responsible for atrial depolarization. *Tract of Sentinel* - This term is not a recognized internodal tract in the cardiac conduction system. - The primary internodal tracts are typically named after Wenckebach, Thorel, and Bachmann. *Tract of Starling* - This term refers to **Starling's law of the heart**, which describes the relationship between end-diastolic volume and stroke volume. - It is not a tract within the cardiac conduction system. *Tract of Moses* - This term is not a recognized anatomical structure or conduction pathway in the context of the heart. - It does not describe any part of the electrical conduction system of the heart.

Q: The contraction of the diaphragm has no effect on which of the following apertures in the diaphragm?

A. ***A*** - Label A points to the **vena cava foramen**, through which the inferior vena cava passes. This opening is located within the **central tendon** of the diaphragm. - The central tendon is **fibrous and non-contractile**, meaning that during diaphragm contraction, the vena cava foramen remains relatively unchanged in size. This ensures continuous venous return to the heart. *B* - Label B points to the **esophageal hiatus**, which transmits the esophagus and vagus nerves. - During diaphragm contraction, this opening **narrows slightly** due to the muscular action, aiding in the prevention of gastroesophageal reflux. *C* - Label C points to the **aortic hiatus**, through which the aorta, azygos vein, and thoracic duct pass. - While located behind the diaphragm, the muscular contraction of the crura surrounding the aortic hiatus can cause it to **change shape**, although it is less affected than the esophageal hiatus. *All of the above* - This option is incorrect because the contraction of the diaphragm **does affect** the esophageal and aortic hiatuses, albeit to varying degrees. - Only the vena cava foramen, located in the non-contractile central tendon, is largely unaffected.

Q: A 15-year-old child with rheumatic heart disease is having hoarseness of voice. Mark the nerve involved in the diagram shown below:

B. ***Correct Option B*** - The image shows the **left recurrent laryngeal nerve** (indicated by label B) looping around the **aortic arch** and ascending towards the larynx. - In rheumatic heart disease, severe **mitral stenosis** can lead to enlargement of the **left atrium**, compressing the left recurrent laryngeal nerve against the aortic arch, resulting in **hoarseness of voice (Ortner's syndrome)**. *Incorrect Option A* - This structure (A) represents the **right recurrent laryngeal nerve**, which typically loops around the **right subclavian artery** and is not usually implicated in Ortner's syndrome due to left atrial enlargement. - While damage to this nerve can also cause hoarsiness, it would not be related to the pathophysiology of cardiac enlargement in rheumatic heart disease. *Incorrect Option C* - This structure (C) represents the **vagus nerve** (cranial nerve X) in the neck, from which the recurrent laryngeal nerves branch. - Direct compression of the vagus nerve in this location is less common as a cause of isolated hoarseness related to cardiac pathology compared to the recurrent laryngeal nerve. *Incorrect Option D* - This structure (D) represents a major blood vessel in the neck, likely the **left common carotid artery** or **left internal jugular vein**, both of which are not directly involved in phonation or compressed by atrial enlargement in a way that causes hoarseness. - These vessels are primarily involved in blood supply to and drainage from the head and neck.

Question 1

A 30-year-old man came with choking episodes after ingestion of fish bone while eating. The fishbone got impacted at the level of T4 in the esophagus. Which is the most likely site of obstruction?

Accepted Answer

Arch of aorta

Answer

Diaphragm

Answer

Left bronchus

Answer

Cricopharyngeus

Question 2

A woman presents with a breast lump, associated with skin dimpling and nipple retraction. What is the most likely anatomical structure responsible for the skin dimpling?

Accepted Answer

Suspensory (Cooper’s) ligaments

Answer

Lactiferous ducts

Answer

Subcutaneous fat

Answer

Pectoral fascia

Question 3

While doing an endoscopy, constriction is felt at the oesophageal junction at 25 cm from the incisor. This is due to?

Accepted Answer

b. Arch of aorta

Answer

d. Diaphragmatic opening

Answer

c. Right bronchus

Answer

a. Inferior vena cava

Question 4

Which of the following structures passes through the foramen marked by the arrow? ![img-53.jpeg](img-53.jpeg)

Accepted Answer

Thoracic duct

Answer

Oesophagus

Answer

Sympathetic trunk

Answer

Inferior vena cava

Question 5

All of the following are superior mediastinal tumors except:

Accepted Answer

Parathyroid

Answer

Thyroid

Answer

Thymus

Answer

Lymphoma

Question 6

Match the cardiac anatomical features from Column I with their corresponding labels from Column II. Column I: 1. Receives oxygenated blood from pulmonary veins; 2. Lies anterior to ascending aorta; 3. Arises from LV; 4. Hypertrophy in pulmonary stenosis. Column II: A. Ascending aorta; B. Right ventricle; C. Pulmonary trunk; D. Left atrium.

Accepted Answer

1-D, 2-C, 3-A, 4-B

Answer

1-A, 2-B, 3-C, 4-D

Answer

1-B, 2-D, 3-C, 4-A

Answer

1-C, 2-A, 3-D, 4-B

Question 7

Which nerve marked as X innervates the Aortic Arch?

Accepted Answer

Aortic depressor nerve

Answer

Carotid sinus nerve

Answer

Inferior cervical cardiac nerve

Answer

Superior cervical cardiac nerve

Question 8

Identify the tract shown as X which is responsible for conduction from SA node to AV node.

Accepted Answer

Tract of Thorel

Answer

Tract of Sentinel

Answer

Tract of Starling

Answer

Tract of Moses

Question 9

The contraction of the diaphragm has no effect on which of the following apertures in the diaphragm?

Accepted Answer

A

Answer

B

Answer

C

Answer

All of the above

Question 10

A 15-year-old child with rheumatic heart disease is having hoarseness of voice. Mark the nerve involved in the diagram shown below:

Accepted Answer

B

Answer

A

Answer

C

Answer

D

Thorax — MCQs

Thorax — MCQs

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