Unit 14 Question Bank
Sourcing: items tagged TMU 2021–22 come from the real final paper. Items tagged
Slide come from the TMU lecture. Items tagged Gray's are built from the textbook to cover
examinable content. Nothing here is invented; answers are verifiable against the cited page — check against
the official marking scheme where one exists.
0 / 20 answered
1The three big branches of the aortic arch, from right to left, are the ( ).
Answer: B
Brachiocephalic trunk · left common carotid · left subclavian. There is no left brachiocephalic trunk because the arch is already on the left, so those vessels arise directly.TMU 2021–22 final, Section III Q3 · TMU Lecture 15 Slide 10
2The right phrenic nerve passes ( ) the root of the right lung.
Answer: C
The phrenic nerve passes anterior to the lung root on both sides; the vagus passes posterior. Phrenic to the front — it is heading for the diaphragm alongside the pericardium.TMU Lecture 15 Slide 6
3The azygos vein arches over the root of the right lung to enter the ( ).
Answer: D
It ascends on the right of the vertebral bodies to T4 and arches forward over the right lung root into the superior vena cava — the landmark of the right lateral mediastinum.TMU Lecture 15 Slide 6
4The right lung has ( ) lobes and ( ) fissures.
Answer: A
Three lobes and two fissures (oblique and horizontal). The left lung has two lobes and only the oblique fissure, plus the cardiac notch and lingula.Gray's 4e p.156
5The left recurrent laryngeal nerve hooks under the ( ).
Answer: B
Under the arch of the aorta, lateral to the arterial ligament, then ascends in the groove between trachea and oesophagus. Its long intrathoracic course is why chest disease can cause hoarseness.TMU Lecture 15 Slide 11
6The arch of the aorta joins the descending aorta at the level of ( ).
Answer: C
At the left side of the body of the fourth thoracic vertebra, the same plane as the sternal angle that divides the mediastinum.TMU Lecture 15 Slide 10
7In the root of the RIGHT lung, the highest structure is the ( ).
Answer: D
On the right the bronchus is highest (the eparterial bronchus passes above the artery); on the left the pulmonary artery is highest, pushed up by the aortic arch. Anterior to posterior is vein–artery–bronchus on both sides.Snell's 10e Ch.5
8Inhaled foreign bodies most often enter the right bronchial tree because the right main bronchus is ( ).
Answer: A
Wider, shorter and more vertical — the heart pushes the left bronchus into a more horizontal course.Snell's 10e Ch.5 (clinical)
9The arterial ligament connects the concavity of the aortic arch to the ( ).
Answer: B
The ligamentum arteriosum, the remnant of the fetal ductus arteriosus, connects the arch to the left pulmonary artery. The left recurrent laryngeal nerve hooks round the arch lateral to it.TMU Lecture 15 Slide 10
10The hemiazygos vein crosses the midline to join the azygos vein at about the level of ( ).
Answer: C
At about T8, passing behind the aorta. The accessory hemiazygos drains the upper left intercostal spaces and also crosses to the azygos.TMU Lecture 15 Slide 12
11Which structure is found on the LEFT side of the mediastinum but not the right?
Answer: D
The hemiazygos and accessory hemiazygos veins lie on the left; the azygos vein and superior vena cava are right-sided landmarks.TMU Lecture 15 Slides 12–13
12The greater splanchnic nerve arises from sympathetic trunk roots ( ).
Answer: A
From the 6th to 9th thoracic ganglia, descending to pierce the diaphragm and reach the coeliac ganglion.TMU Lecture 15 Slide 9
13The lower part of the thoracic duct ascends with ( ).
Answer: B
It ascends through the posterior mediastinum with the aorta on its left, the azygos vein on its right, and the oesophagus in front.TMU Lecture 15 Slide 8
14The cardiac notch and lingula are features of the ( ).
Answer: C
Both belong to the left lung, where the heart indents its anterior border.Gray's 4e p.158
15The left vagus nerve gives off the left recurrent laryngeal nerve at the level of the ( ).
Answer: D
At the aortic arch. The right recurrent laryngeal nerve leaves the right vagus much higher, at the right subclavian artery in the root of the neck.TMU Lecture 15 Slide 11
16In the lung root, the order from anterior to posterior is ( ).
Answer: A
Vein, artery, bronchus from front to back — the same on both sides. Only the vertical order differs between right and left.Snell's 10e Ch.5
17Rib notching on a chest X-ray in coarctation of the aorta is caused by ( ).
Answer: B
Blood bypasses the narrowing through the internal thoracic and posterior intercostal arteries, which enlarge and erode the under-surfaces of the ribs.Snell's 10e Ch.5 (clinical)
18Superior vena cava obstruction is compensated for by the ( ).
Answer: C
The azygos system links the SVC and IVC territories, so blood from the head and arms can reverse down dilated chest wall veins into the IVC.Snell's 10e Ch.5 (clinical)
19The right vagus nerve lies ( ) the superior vena cava.
Answer: D
Behind the SVC, on the right side of the trachea, then passing behind the right lung root to reach the oesophagus.TMU Lecture 15 Slide 8
20Which lung is shorter and wider, and why?
Answer: A
The right lung is shorter and wider — shorter because the liver pushes the right hemidiaphragm up, and wider because the heart is not on that side.TMU Lecture 14 Slide 19
1 Branches of the aortic arch — asked 2021–22 · 3′+
From right to left:
1. Brachiocephalic trunk — dividing into the right common carotid and right subclavian arteries
2. Left common carotid artery
3. Left subclavian artery
The arch begins and ends at the plane of the sternal angle, joining the descending aorta at the left side of the body of T4.TMU 2021–22 Section III Q3 · TMU Lecture 15 Slide 10
1. Brachiocephalic trunk — dividing into the right common carotid and right subclavian arteries
2. Left common carotid artery
3. Left subclavian artery
The arch begins and ends at the plane of the sternal angle, joining the descending aorta at the left side of the body of T4.TMU 2021–22 Section III Q3 · TMU Lecture 15 Slide 10
2 Arterial ligament (ligamentum arteriosum) — 2′+
A fibrous band connecting the concavity of the aortic arch to the left pulmonary artery — the remnant of the fetal ductus arteriosus.
The left recurrent laryngeal nerve hooks under the arch lateral to it, which is why the nerve is vulnerable to disease in the chest.TMU Lecture 15 Slide 10
The left recurrent laryngeal nerve hooks under the arch lateral to it, which is why the nerve is vulnerable to disease in the chest.TMU Lecture 15 Slide 10
3 Root of the lung — 3′+
The stalk connecting each lung to the mediastinum, containing the principal bronchus, pulmonary artery, two pulmonary veins, bronchial vessels, lymphatics and nerves, enclosed in a pleural sleeve continued below as the pulmonary ligament.
Anterior → posterior (both sides): vein · artery · bronchus.
Superior → inferior: right — bronchus highest; left — artery highest.
The phrenic nerve passes in front and the vagus behind the root on both sides.Snell's 10e Ch.5
Anterior → posterior (both sides): vein · artery · bronchus.
Superior → inferior: right — bronchus highest; left — artery highest.
The phrenic nerve passes in front and the vagus behind the root on both sides.Snell's 10e Ch.5
4 Azygos vein — 3′+
An unpaired vein ascending on the right side of the thoracic vertebral bodies to the level of T4, where it arches forward over the root of the right lung to enter the superior vena cava.
It drains the right posterior intercostal veins and receives the hemiazygos and accessory hemiazygos veins from the left.
Clinical: it links the SVC and IVC territories and provides the collateral route in caval obstruction.TMU Lecture 15 Slide 6
It drains the right posterior intercostal veins and receives the hemiazygos and accessory hemiazygos veins from the left.
Clinical: it links the SVC and IVC territories and provides the collateral route in caval obstruction.TMU Lecture 15 Slide 6
5 Right lateral mediastinum — structures — picture question+
Arch of the azygos vein over the lung root into the SVC · superior vena cava and right brachiocephalic vein · right phrenic nerve in front of the lung root with pericardiacophrenic vessels · right vagus nerve behind the lung root · trachea and oesophagus · thoracic duct · right sympathetic trunk and greater splanchnic nerve (T6–T9).TMU Lecture 15 Slides 6–9
6 Left lateral mediastinum — structures — picture question+
Arch of the aorta over the lung root, with the arterial ligament and the left recurrent laryngeal nerve hooking under it · left phrenic nerve in front of the lung root · left vagus nerve behind it, forming the oesophageal plexus · descending thoracic aorta · oesophagus · upper thoracic duct · hemiazygos and accessory hemiazygos veins · left sympathetic trunk.TMU Lecture 15 Slides 10–13
1
Please write down the three big branches of the aortic arch (from left to right).
6′
Real question — TMU 2021–22 final, Section III Q3.
Position of the arch
The arch of the aorta lies in the superior mediastinum, beginning and ending at the plane of the sternal angle, and joining the descending aorta at the left side of the body of T4. Its concavity is connected to the left pulmonary artery by the arterial ligament.
The three branches, from RIGHT to LEFT
- Brachiocephalic trunk — which divides behind the right sternoclavicular joint into the right common carotid and right subclavian arteries
- Left common carotid artery
- Left subclavian artery
(Listed from left to right the order is simply reversed: left subclavian, left common carotid, brachiocephalic trunk.)
Point worth adding
There is no left brachiocephalic trunk. The arch already lies on the left, so the left carotid and subclavian arteries arise directly from it, whereas the right-sided vessels share a common stem to reach across the midline. The same asymmetry explains why the left recurrent laryngeal nerve hooks around the arch while the right hooks around the right subclavian artery in the neck.
Marking guide: three branches correctly named 3 · division of the brachiocephalic trunk 1 · position/level of the arch 1 · explanation of the asymmetry 1.
2
Describe the structures seen on the right side of the mediastinum after removal of the right lung.
8′
The dominant landmark
The arch of the azygos vein, which ascends on the right of the vertebral bodies to T4 and arches forward over the root of the right lung to enter the superior vena cava.
Vessels
- Superior vena cava and the right brachiocephalic vein
- Right posterior intercostal veins, ending in the azygos vein
- The brachiocephalic trunk lies medial and posterior to the SVC, dividing into right common carotid and right subclavian arteries
Nerves
- Right phrenic nerve — descends on the right of the SVC and passes in front of the lung root with the pericardiacophrenic vessels, to the diaphragm
- Right vagus nerve — lies behind the SVC on the side of the trachea and passes behind the lung root
- Right sympathetic trunk, about twelve ganglia, lateral to the azygos vein
- Greater splanchnic nerve, from roots T6–T9
Other structures
- Trachea and oesophagus, the oesophagus descending behind the pericardium
- Lower thoracic duct, with the aorta on its left, the azygos vein on its right and the oesophagus in front
The single relationship most often examined: phrenic in front of the lung root, vagus behind it.
Marking guide: azygos arch 2 · SVC 1 · phrenic in front 1.5 · vagus behind 1.5 · sympathetic/splanchnic 1 · oesophagus or thoracic duct 1.
3
Describe the structures seen on the left side of the mediastinum after removal of the left lung.
8′
The dominant landmark
The arch of the aorta, curving over the root of the left lung and joining the descending aorta at the left side of the body of T4. Its concavity is connected to the left pulmonary artery by the arterial ligament.
Arteries
The three branches of the arch — brachiocephalic trunk, left common carotid and left subclavian — and the descending thoracic aorta.
Nerves
- Left phrenic nerve with pericardiacophrenic vessels — in front of the lung root
- Left vagus nerve — crosses the left side of the aortic arch and passes behind the lung root, forming the oesophageal plexus
- Left recurrent laryngeal nerve — leaves the vagus at the arch, hooks under it lateral to the arterial ligament, and ascends in the groove between trachea and oesophagus
- Left sympathetic trunk, lateral to the hemiazygos vein
Veins
- Hemiazygos vein — in front of the left side of the lower thoracic vertebrae, crossing to the azygos at about T8
- Accessory hemiazygos vein — on the left of the upper vertebrae
- Left posterior intercostal veins ending in both
Other
The oesophagus, between the pericardium and the descending aorta, and the upper thoracic duct, behind the origin of the left subclavian artery.
Marking guide: aortic arch and level 2 · arterial ligament 0.5 · phrenic in front 1 · vagus behind and oesophageal plexus 1.5 · recurrent laryngeal course 1.5 · hemiazygos veins 1.5.
4
Compare the right and left lungs.
6′
| Right lung | Left lung | |
|---|---|---|
| Shape | Shorter and wider | Longer and narrower |
| Reason | Liver raises the right hemidiaphragm | Heart projects to the left |
| Lobes | Three — superior, middle, inferior | Two — superior, inferior |
| Fissures | Oblique and horizontal | Oblique only |
| Special features | — | Cardiac notch and lingula |
| Root — highest structure | Bronchus | Pulmonary artery |
| Mediastinal relations | Azygos arch, SVC, oesophagus, trachea | Aortic arch, descending aorta, oesophagus |
Clinical consequence of the difference
The right main bronchus is wider, shorter and more vertical than the left, because the heart displaces the left bronchus into a more horizontal course. Inhaled foreign bodies and aspirated material therefore enter the right bronchial tree far more often — typically the posterior segment of the right upper lobe in a supine patient, or the basal segments in an upright one.
Marking guide: shape and reason 1 · lobes 1 · fissures 1 · left-lung features 1 · root difference 1 · bronchial asymmetry with clinical point 1.
5
Describe the azygos system of veins and its clinical importance.
6′
Composition
| Vein | Course | Drains |
|---|---|---|
| Azygos | Ascends on the right of the vertebral bodies to T4, then arches over the right lung root into the superior vena cava | Right posterior intercostal veins; receives the hemiazygos veins |
| Hemiazygos | Ascends on the left, crosses the midline behind the aorta at about T8 | Lower left posterior intercostal veins |
| Accessory hemiazygos | Descends on the left upper vertebrae, crosses to the azygos | Upper left posterior intercostal veins |
Function
It drains the thoracic wall and forms a continuous venous channel connecting the inferior vena cava below with the superior vena cava above.
Clinical importance
- In superior vena cava obstruction — most often by a bronchial carcinoma — blood from the head and upper limbs reverses down dilated chest wall veins into the azygos system and reaches the IVC. The patient has a swollen plethoric face and neck, distended non-pulsatile neck veins and visible chest wall collaterals.
- In inferior vena cava obstruction the flow reverses the other way, upward to the SVC.
- The azygos arch is a landmark on the right lateral mediastinum and on CT.
Marking guide: three veins named with courses 3 · crossing level 0.5 · SVC–IVC connection 1 · one clinical syndrome explained 1.5.