Thorax Practice Questions

Q: Which of the following is the MAJOR tributary of the coronary sinus?

Great cardiac vein. ***Great cardiac vein*** - The **great cardiac vein** is the largest and most significant tributary, draining areas supplied by the **left main coronary artery** and its branches. - It runs in the **anterior interventricular groove**, accompanying the anterior interventricular artery, and then curves around the left side of the heart to empty into the coronary sinus. *Anterior cardiac vein* - The **anterior cardiac veins** typically drain directly into the **right atrium**, bypassing the coronary sinus [1]. - They primarily drain the anterior surface of the **right ventricle**. *Thebesian vein* - The **Thebesian veins** (venae cordis minimae) are small veins that open directly into the **chambers of the heart**, not the coronary sinus. - They are responsible for a small amount of **physiological shunt** of deoxygenated blood into the left heart chambers. *Oblique vein of Marshall* - The **oblique vein of Marshall** (oblique vein of the left atrium) is a small vein originating from the posterior wall of the left atrium. - It is a **remnant of the left superior vena cava** and empties into the left extremity of the coronary sinus, but it is not considered the major tributary in terms of blood flow volume.

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.

Q: Intercostal nerve is a branch of?

Ventral rami of thoracic spinal nerves. ***Ventral rami of thoracic spinal nerves*** - Intercostal nerves are direct continuations of the **ventral rami of the thoracic spinal nerves** (T1-T11) [1]. - These nerves run within the **intercostal spaces**, providing sensory and motor innervation to the thoracic wall [2]. *Brachial plexus* - The brachial plexus is formed by the **ventral rami of spinal nerves C5-T1**. - It primarily innervates the **upper limb**, not the intercostal spaces. *Dorsal rami of thoracic spinal nerves* - The dorsal rami of thoracic spinal nerves supply the **deep back muscles** and the skin over the back. - They do not contribute to the innervation of the intercostal spaces or the anterior/lateral thoracic wall. *Ventral rami of cervical spinal nerves* - The ventral rami of cervical spinal nerves form the **cervical plexus (C1-C4)** and contribute to the **brachial plexus (C5-T1)**. - They innervate structures in the neck, diaphragm, and upper limb, but not the intercostal region.

Q: What is the average number of lobes in a human breast?

15. ***15*** - Historically, the human breast was described as containing **15 to 20 lobes**, each being a functionally distinct unit for milk production arranged radially around the nipple [1]. - This was the accepted anatomical teaching at the time of this examination. - **Note:** Modern imaging studies (MRI, ultrasound) have since shown that breasts typically contain **7-10 ductal systems/lobes** rather than 15-20, representing an important update to classical anatomy teaching. *5* - This number is too low and does not represent either the classical (15-20) or modern (7-10) understanding of breast lobe anatomy. - Insufficient to account for the complexity of the mammary ductal system. *10* - This represents the **upper range of modern anatomical understanding** (7-10 lobes based on current imaging studies). - While anatomically accurate by today's standards, the classical teaching referenced in this examination specified 15-20 lobes as average. *20* - Represents the **upper limit** of the classical range (15-20 lobes) [1]. - While within the historical normal range, **15 is considered the more typical average** in classical anatomy texts. - Modern research indicates this number significantly overestimates the actual lobe count.

Q: Which of the following does not directly drain into right atrium?

Great cardiac vein. ***Great cardiac vein*** - The **great cardiac vein** drains into the **coronary sinus**, which then empties into the right atrium [1]. - It does not drain directly into the right atrium, distinguishing it from the other options. *Inferior vena cava* - The **inferior vena cava** is one of the major vessels that drains directly into the **right atrium**. - It carries deoxygenated blood from the lower body to the right atrium. *Anterior cardiac vein* - The **anterior cardiac veins** drain directly into the **right atrium**. - They tend to drain the anterior surface of the right ventricle. *Venae cordis minimi* - Also known as **Thebesian veins**, these are small veins that drain directly into the cardiac chambers, including the **right atrium**. - They represent a direct communication between the myocardial capillaries and the cardiac chambers.

Q: Which of the following statements about the atrioventricular groove is true?

Also called coronary sulcus. ***Also called coronary sulcus*** - The **atrioventricular groove** is a critical anatomical landmark that separates the atria from the ventricles on the external surface of the heart. - This anatomical division is consistently referred to as the **coronary sulcus**, which encircles the entire heart. *Contains left anterior descending coronary artery* - The **left anterior descending (LAD) coronary artery**, also known as the anterior interventricular artery, lies within the **interventricular groove** (or sulcus), not the atrioventricular groove. - The interventricular groove separates the left and right ventricles, distinct from the atrioventricular separation. *Contains left coronary artery* - The **left coronary artery (LCA)** is a short main trunk that almost immediately divides into the **left anterior descending** (LAD) and **circumflex arteries** [1]. - While the **circumflex artery** (a branch of the LCA) runs in the left part of the atrioventricular groove, the main left coronary artery itself is too short to be considered within the groove [1]. *Contains posterior descending artery* - The **posterior descending artery (PDA)**, also known as the posterior interventricular artery, lies within the **posterior interventricular groove**, separating the ventricles posteriorly. - The PDA is a branch of either the right coronary artery (in most people) or the circumflex artery, but it follows the interventricular septum, not the atrioventricular border.

Q: Right border of heart is formed by?

Right atrium. ***Right atrium*** - The **right atrium** forms the major part of the **right border of the heart** as viewed in a posteroanterior (PA) chest X-ray. - Its position is along the right sternal margin, extending from the level of the third costal cartilage superiorly to the sixth costal cartilage inferiorly. *Right ventricle* - The **right ventricle** primarily forms the **anterior surface** and part of the inferior border of the heart. - It contributes minimally, if at all, to the visible right border in a standard PA view. *SVC* - The **superior vena cava (SVC)** drains into the right atrium and is located superior to it. - While it's adjacent to the right border, it does **not form the actual right border of the heart itself**. *IVC* - The **inferior vena cava (IVC)** drains into the right atrium from below. - It is positioned inferiorly and posteriorly, and therefore **does not form the right border** of the heart in a PA view.

Q: Which of the following structures does not pass through the superior thoracic aperture?

Right recurrent laryngeal nerve. ***Right recurrent laryngeal nerve*** - The **right recurrent laryngeal nerve** loops around the **right subclavian artery** in the neck [1] and ascends into the neck to innervate the larynx. - It does not descend into the thorax before recurring, thus it does not pass through the superior thoracic aperture [1]. *Right vagus* - The **right vagus nerve** passes through the superior thoracic aperture anterior to the right subclavian artery and enters the thorax. - It then descends posterior to the right brachiocephalic vein and superior vena cava before supplying thoracic and abdominal viscera. *Right brachiocephalic artery* - The **right brachiocephalic artery** (also known as the brachiocephalic trunk) is the first branch of the aortic arch and passes superiorly through the superior thoracic aperture. - It gives rise to the right common carotid artery and right subclavian artery in the neck. *Thoracic duct* - The **thoracic duct** ascends from the abdomen through the posterior mediastinum, passes through the superior thoracic aperture to enter the neck [2]. - In the neck, it arches laterally and empties into the left subclavian vein, or the junction of the left internal jugular and subclavian veins.

Q: What is the uppermost structure in left lung hilum?

Pulmonary artery. ***Pulmonary artery*** - In the **left lung hilum**, the **pulmonary artery** typically lies superior to the bronchus. - This anatomical position helps differentiate it from the relations in the right lung hilum, where the pulmonary artery is anterior to the bronchus. *Pulmonary vein* - The **pulmonary veins** are usually located anterior and inferior to the bronchus in both lung hila. - They tend to be the most anterior and inferior structures carrying oxygenated blood from the lungs. *Bronchial artery* - **Bronchial arteries** are smaller vessels that typically run on the posterior surface of the bronchi. - They are not considered the uppermost main structure in the hilum. *Left mainstem bronchus* - The **left mainstem bronchus** is usually found inferior to the pulmonary artery and posterior to the pulmonary veins in the left hilum. - It is a prominent structure but not the most superior.

Q: Which vein is found at the apex of the heart?

Great cardiac vein. ***Great cardiac vein*** - The **great cardiac vein** originates near the **apex of the heart** and ascends in the anterior interventricular groove. - It drains blood from the anterior aspects of both ventricles and the left atrium. *Coronary sinus* - The **coronary sinus** is a large venous structure located on the posterior surface of the heart, not at the apex. - It receives most of the venous blood from the myocardium and empties into the right atrium. *Anterior cardiac vein* - The **anterior cardiac veins** typically run across the anterior surface of the right ventricle and drain directly into the right atrium, bypassing the coronary sinus. - They are generally smaller and not found at the apex of the heart. *Middle cardiac vein* - The **middle cardiac vein** runs in the posterior interventricular groove, on the diaphragmatic surface of the heart. - It originates near the apex but on the posterior aspect, making it primarily a posterior vessel.

Question 1

Which of the following is the MAJOR tributary of the coronary sinus?

Accepted Answer

Great cardiac vein

Answer

Anterior cardiac vein

Answer

Thebesian vein

Answer

Oblique vein of Marshall

Question 2

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

Question 3

Intercostal nerve is a branch of?

Accepted Answer

Ventral rami of thoracic spinal nerves

Answer

Brachial plexus

Answer

Dorsal rami of thoracic spinal nerves

Answer

Ventral rami of cervical spinal nerves

Question 4

What is the average number of lobes in a human breast?

Accepted Answer

15

Answer

5

Answer

10

Answer

20

Question 5

Which of the following does not directly drain into right atrium?

Accepted Answer

Great cardiac vein

Answer

Inferior vena cava

Answer

Anterior cardiac vein

Answer

Venae cordis minimi

Question 6

Which of the following statements about the atrioventricular groove is true?

Accepted Answer

Also called coronary sulcus

Answer

Contains left anterior descending coronary artery

Answer

Contains posterior descending artery

Answer

Contains left coronary artery

Question 7

Right border of heart is formed by?

Accepted Answer

Right atrium

Answer

Right ventricle

Answer

SVC

Answer

IVC

Question 8

Which of the following structures does not pass through the superior thoracic aperture?

Accepted Answer

Right recurrent laryngeal nerve

Answer

Right vagus

Answer

Right brachiocephalic artery

Answer

Thoracic duct

Question 9

What is the uppermost structure in left lung hilum?

Accepted Answer

Pulmonary artery

Answer

Pulmonary vein

Answer

Bronchial artery

Answer

Left mainstem bronchus

Question 10

Which vein is found at the apex of the heart?

Accepted Answer

Great cardiac vein

Answer

Coronary sinus

Answer

Anterior cardiac vein

Answer

Middle cardiac vein

Thorax — MCQs

Thorax — MCQs

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