Thorax Practice Questions

Q: Identify the type of joint in the image provided.

Synovial joint. ***Synovial joint*** - The image depicts a **costotransverse joint**, which connects a rib to a thoracic vertebra. These joints are **diarthrotic**, meaning they are freely movable, characteristic of synovial joints. - Synovial joints are characterized by the presence of a **synovial cavity**, articular cartilage, an articular capsule, and synovial fluid, allowing for a wide range of motion. *Syndesmosis* - A syndesmosis is a type of **fibrous joint** where two bones are joined by a ligament or a membrane, allowing for very limited movement, such as the distal tibiofibular joint. - This definition does not match the image, which shows a joint designed for movement between the rib and vertebra. *Synarthrosis* - Synarthrosis is a classification for **immovable joints**, such as sutures in the skull. - The costotransverse joints, as shown, allow for movement during respiration and are therefore not synarthrotic. *Symphysis* - A symphysis is a type of **cartilaginous joint** where bones are joined by **fibrocartilage**, allowing for slight movement. Examples include the pubic symphysis or intervertebral discs. - The costotransverse joint shown in the image is a synovial articulation, not a cartilaginous joint.

Q: Which of the following statements about Sibson's fascia is correct?

Covers apical part of lung. ***Covers apical part of lung*** - **Sibson's fascia**, also known as the **suprapleural membrane**, is a dense fascial layer that covers and reinforces the **apex of the lung** and pleura. - It protects the lung apex and helps to support structures in the **root of the neck**. *Part of scalenus anterior muscle* - Sibson's fascia is a **separate fascial structure** extending from the first rib to the C7 transverse process, and is not a part of the scalenus anterior muscle. - The **scalenus anterior muscle** is one of the muscles of the neck, and while anatomically related by proximity to the fascia, it is not structurally part of it. *Vessel pass above the fascia* - Key neurovascular structures like the **subclavian artery** and the **brachial plexus** pass *below* Sibson's fascia, as the fascia protects the lung apex. - The fascia acts as a barrier, separating the lung apex from the more superficial structures of the neck. *Attached to the inner border of 2nd rib* - Sibson's fascia is primarily attached to the **inner border of the first rib** and the transverse process of the seventh cervical vertebra. - Its attachment to the first rib is crucial for its supportive role over the lung apex.

Q: What type of joint is formed by the costal cartilages of the 8th and 9th ribs?

Interchondral joint. ***Interchondral joint*** - The **8th, 9th, and 10th costal cartilages** articulate with the cartilage immediately above them, forming **interchondral joints**. - These are typically **synovial plane joints** that allow for some gliding movement during respiration. *Costochondral joint* - This joint type is formed between the **rib bone** and its respective **costal cartilage**. - These are **primary cartilaginous joints (synchondroses)** and are generally immobile. *Synovial joint* - While interchondral joints are a type of synovial joint, this option is too general and does not specify the unique anatomical arrangement. - Synovial joints are characterized by a **joint capsule**, **synovial fluid**, and **articular cartilage**, allowing for free movement. *Costovertebral joint* - This joint is formed between the **head of a rib** and the **bodies of two adjacent vertebrae** and their intervertebral disc. - It is a **synovial plane joint** crucial for respiratory mechanics, but not related to the articulation of costal cartilages with each other.

Q: Which of the following structures does not pass through the aortic opening?

Phrenic nerve. Phrenic nerve - The **phrenic nerve** passes through the **caval opening** (venae caval foramen) in the central tendon of the diaphragm, along with the inferior vena cava, or pierces the diaphragm anteriorly. - It does not pass through the **aortic opening**, which is located more posteriorly and inferiorly [1]. *Azygos vein* - The **azygos vein** typically passes through the **aortic opening** of the diaphragm alongside the aorta and thoracic duct. - This anatomical arrangement allows the vein to ascend into the thorax from the abdomen. *Aorta* - The **aorta** itself, specifically the **descending thoracic aorta**, passes through the **aortic opening** to become the abdominal aorta. - This is the largest of the three major diaphragm openings, located anterior to the 12th thoracic vertebra. *Thoracic duct* - The **thoracic duct**, the main lymphatic vessel of the body, also passes through the **aortic opening** of the diaphragm. - It accompanies the aorta and azygos vein as it ascends from the abdomen into the thorax.

Q: Which of the following is not seen in the anterior mediastinum?

Neurogenic tumor. ***Neurogenic tumor*** - **Neurogenic tumors** typically arise from nerve tissue and are most commonly found in the **posterior mediastinum**. - The posterior mediastinum is the primary location for these tumors due to the presence of the **sympathetic chain**, intercostal nerves, and vagus nerve. *Thyroid tumour* - **Ectopic thyroid tissue** can be found in the anterior mediastinum, and this tissue can give rise to thyroid tumors [1]. - While less common than in the neck, substernal or **ectopic thyroid goiters** and carcinomas can present in this compartment [1]. *Thymoma* - The **thymus gland** is located in the anterior mediastinum, making thymoma (a tumor of the thymus) a classic anterior mediastinal mass [1]. - Thymomas are often associated with **paraneoplastic syndromes** like myasthenia gravis. *Lymphoma* - **Lymphatic tissue**, including lymph nodes, is plentiful in the anterior mediastinum [1]. - **Hodgkin's and non-Hodgkin's lymphoma** frequently present as masses in the anterior mediastinum, often causing symptoms due to compression of surrounding structures [1].

Q: Anterior Mediastinal nodes are included in which level of lymph nodes?

VI. ***VI*** - Level VI lymph nodes are the **prevascular and retrotracheal nodes** located in the **anterior mediastinum** [1]. - According to the **IASLC (International Association for the Study of Lung Cancer)** lymph node mapping system, Level 6 nodes are specifically classified as anterior mediastinal nodes [1]. - These include nodes anterior to the superior vena cava and ascending aorta, and nodes between the trachea and esophagus [1]. *I* - Level I lymph nodes are located in the **low cervical, supraclavicular, and sternal notch** regions. - These are **extra-thoracic nodes** and not part of the mediastinal compartments. - They represent the highest mediastinal, supraclavicular, and sternal notch nodes [1]. *V* - Level V lymph nodes are the **subaortic (aortopulmonary window)** nodes [1]. - These are located in the space between the **aorta and pulmonary artery**, lateral to the ligamentum arteriosum [1]. - While mediastinal, they are specifically in the aortopulmonary window, not classified as anterior mediastinal. *VII* - Level VII lymph nodes are the **subcarinal nodes** located below the carina in the **middle mediastinum** [1]. - These nodes are positioned in the space beneath where the trachea bifurcates into the main bronchi [1]. - They are classified as middle mediastinal nodes, not anterior mediastinal nodes.

Q: Food can commonly get obstructed in the esophagus at all of the following locations except

Crossing of the hemiazygous vein. Food can commonly get obstructed in the esophagus at all of the following locations except ***Crossing of the hemiazygous vein*** - The **hemiazygos vein crosses the vertebral column** at T7-T9 to drain into the azygos vein; however, this anatomical relationship does not typically create a constriction or point of obstruction for the esophagus. - While it is in proximity, its course does not physically compress or narrow the esophageal lumen in a manner that would commonly cause food impaction. *Crossing of left bronchus* - The **left main bronchus crosses anterior to the esophagus** at the level of the carina (T4-T5), causing a natural indentation and narrowing of the esophageal lumen. - This anatomical narrowing, coupled with the rigid structure of the bronchus, makes it a common site for food impaction, especially for larger boluses. *Crossing of arch of aorta* - The **arch of the aorta crosses anterior and to the left of the esophagus** at the level of T3-T4, creating another significant anatomical constriction. - This bending and compression by a large, typically pulsatile vessel forms a natural bottleneck where swallowed food can easily become lodged. *Diaphragmatic aperture* - The **esophageal hiatus of the diaphragm** (T10) is the most distal natural esophageal narrowing, where the esophagus passes through a muscular opening before joining the stomach. - This narrow opening, surrounded by the crura of the diaphragm, is a very common site for food impaction, particularly when the opening is physiologically or pathologically narrowed (e.g., in cases of hiatal hernia or tight diaphragmatic attachments).

Q: Which is the narrowest portion of the esophagus?

At the cricopharyngeal sphincter. ***At the cricopharyngeal sphincter*** - This is the **upper esophageal sphincter (UES)**, representing the **narrowest point of the entire esophagus** with a diameter of approximately **14 mm**. - It is formed by the **cricopharyngeus muscle**, which remains tonically contracted at rest to prevent air entry into the esophagus during respiration. - Located approximately **15 cm from the incisor teeth** at the level of the **C6 vertebra**. - **Clinical significance**: This is the most common site for impaction of foreign bodies and is a critical point during endoscopy. *At the crossing of the left main bronchus* - This represents the **middle constriction** where the esophagus is indented by the **left main bronchus** (approximately 22-23 cm from incisors). - This is a point of **extrinsic compression** rather than an intrinsic anatomical narrowing. - Diameter here is approximately **15.5 mm**, making it wider than the upper esophageal sphincter. - Foreign bodies and food boluses may lodge here, but it is not the narrowest point. *At the level of the aortic arch* - The **aortic arch** causes significant indentation and extrinsic compression, adjacent to the bronchial constriction. - This is also part of the **middle constriction** of the esophagus. - Despite this indentation, the lumen diameter is still greater than at the cricopharyngeal sphincter. *At the diaphragmatic aperture* - The esophagus passes through the **esophageal hiatus** at the level of **T10 vertebra** (approximately 40 cm from incisors). - This represents the **lower constriction** with a diameter of approximately **16-19 mm**. - While clinically important for hiatal hernias and lower esophageal sphincter pathology, it is the **widest of the three anatomical constrictions**.

Q: Arch of aorta begins at which vertebral level?

T4. ***T4*** - The **arch of the aorta** typically begins at the level of the **upper border of the fourth thoracic vertebra (T4)**. - This anatomical landmark is crucial for understanding the **topography of the mediastinum** and the branching of the great vessels. *T2* - The **T2 vertebral level** is too high; the arch of the aorta does not begin this superiorly. - This level is often associated with structures like the **trachea** and **esophagus** in the superior mediastinum, but not the aortic arch's origin. *T3* - The **T3 vertebral level** is also too high for the typical origin of the aortic arch. - The **manubrium of the sternum** generally extends down to this level, but the aorta's arch begins slightly lower. *T5* - The **T5 vertebral level** is too low; at this point, the arch of the aorta has usually already passed posteriorly and begun its descent as the **descending aorta** [1]. - The **bifurcation of the trachea** typically occurs at the T4/T5 intervertebral disc level. *T2* - The left recurrent laryngeal nerve (RLN) separates from the vagus as it passes anterior to the arch of the aorta [1].

Q: Which artery supplies the anterior part of the interventricular septum?

Left anterior descending artery (LAD). ***Left anterior descending artery (LAD)*** - The **LAD** is a branch of the **left main coronary artery** and is also known as the "widowmaker" due to its critical supply to a large portion of the left ventricle and the interventricular septum [1]. - It gives rise to **septal branches** that typically supply the anterior two-thirds of the interventricular septum [1]. *Right coronary artery* - The **right coronary artery (RCA)** primarily supplies the **right ventricle**, the right atrium, the SA node (in 60% of people), and the AV node (in 90% of people). - It typically supplies the **inferior wall** of the left ventricle and the posterior one-third of the interventricular septum [1]. *Posterior descending coronary artery* - The **posterior descending artery (PDA)** arises from the **RCA** (in approximately 85% of individuals, known as right dominance) or less commonly from the circumflex artery (in left dominance) [1]. - It supplies the **posterior one-third** of the interventricular septum and typically the inferior wall of the left ventricle [1]. *None of the options* - This option is incorrect because the **LAD** clearly and predominantly supplies the anterior part of the interventricular septum.

Question 1

Identify the type of joint in the image provided.

Accepted Answer

Synovial joint

Answer

Syndesmosis

Answer

Synarthrosis

Answer

Symphysis

Question 2

Which of the following statements about Sibson's fascia is correct?

Accepted Answer

Covers apical part of lung

Answer

Part of scalenus anterior muscle

Answer

Vessel pass above the fascia

Answer

Attached to the inner border of 2nd rib

Question 3

What type of joint is formed by the costal cartilages of the 8th and 9th ribs?

Accepted Answer

Interchondral joint

Answer

Synovial joint

Answer

Costochondral joint

Answer

Costovertebral joint

Question 4

Which of the following structures does not pass through the aortic opening?

Accepted Answer

Phrenic nerve

Answer

Aorta

Answer

Thoracic duct

Answer

Azygos vein

Question 5

Which of the following is not seen in the anterior mediastinum?

Accepted Answer

Neurogenic tumor

Answer

Thyroid tumor

Answer

Lymphoma

Answer

Thymoma

Question 6

Anterior Mediastinal nodes are included in which level of lymph nodes?

Accepted Answer

VI

Answer

I

Answer

V

Answer

VII

Question 7

Food can commonly get obstructed in the esophagus at all of the following locations except

Accepted Answer

Crossing of the hemiazygous vein

Answer

Crossing of left bronchus

Answer

Crossing of arch of aorta

Answer

Diaphragmatic aperture

Question 8

Which is the narrowest portion of the esophagus?

Accepted Answer

At the cricopharyngeal sphincter

Answer

At the diaphragmatic aperture

Answer

At the crossing of the left main bronchus

Answer

At the level of the aortic arch

Question 9

Arch of aorta begins at which vertebral level?

Accepted Answer

T4

Answer

T2

Answer

T5

Answer

T3

Question 10

Which artery supplies the anterior part of the interventricular septum?

Accepted Answer

Left anterior descending artery (LAD)

Answer

Right coronary artery

Answer

Posterior descending coronary artery

Answer

None of the options

Thorax — MCQs

Thorax — MCQs

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