Unit 12 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
1In the costal groove of the rib, the arrangement from up to down is the ( ).
Answer: C
Vein, artery, nerve from above downwards — VAN. The bundle lies in the costal groove of the upper rib of the space, between the internal and innermost intercostal muscles.TMU 2021–22 final, Section II Q1 · TMU Lecture 14 Slide 21
2A chest drain should be inserted ( ).
Answer: D
Just above the upper border of the rib below, where only the small collateral branch lies. Inserting along the lower border of a rib strikes the main neurovascular bundle.Gray's 4e p.136 (clinical application)
3The costodiaphragmatic recess is the interval between the ( ).
Answer: A
Between the costal and diaphragmatic parts of the parietal pleura. It is the lowest part of the pleural cavity and where fluid collects first.TMU 2021–22 definition 8 · TMU Lecture 14 Slide 16
4Which is NOT one of the four parts of the parietal pleura?
Answer: B
The visceral pleura covers the lung and is not part of the parietal pleura. The four parietal parts are cupula, costal, mediastinal and diaphragmatic.TMU Lecture 14 Slide 15
5The external intercostal muscle acts in ( ) and its fibres run ( ).
Answer: C
Inspiration, with fibres running downward and forward. The internal intercostal runs at right angles to it and acts in expiration.TMU Lecture 14 Slide 5
6The anterior intercostal arteries arise from the ( ).
Answer: D
From the internal thoracic artery, supplying the upper six intercostal spaces. The posterior intercostal arteries come from the thoracic aorta.TMU Lecture 14 Slide 11
7The two terminal branches of the internal thoracic artery are the ( ).
Answer: A
The superior epigastric and musculophrenic arteries. The pericardiacophrenic and anterior intercostals are branches along its course, not terminal ones.TMU Lecture 14 Slide 13
8The cupula of the pleura extends above the medial third of the clavicle by about ( ).
Answer: B
2–3 cm, over the apex of the lung into the root of the neck — which is why a subclavian line or a neck stab wound can cause a pneumothorax.TMU Lecture 14 Slide 15
9The lower border of the LUNG in the midaxillary line lies at the ( ).
Answer: C
Lung: 6th · 8th · 10th rib at the midclavicular, midaxillary and paravertebral lines. Pleura is always two ribs lower: 8th · 10th · 12th.TMU Lecture 14 Slide 17
10The neurovascular bundle of an intercostal space lies between the ( ).
Answer: D
Between the internal and innermost intercostal muscles, in the costal groove — a plane analogous to the transversus abdominis plane in the abdominal wall.Gray's 4e p.136
11Which pleura is sensitive to pain?
Answer: A
The parietal pleura is supplied by the intercostal and phrenic nerves and localises pain precisely. The visceral pleura has only autonomic supply and is insensitive — one reason lung cancer presents late.Gray's 4e p.150
12The pulmonary ligament is ( ).
Answer: B
A double fold of mediastinal pleura hanging below the lung root, allowing the root structures to move during respiration. The ductus remnant is the arterial ligament.TMU Lecture 14 Slide 15
13The pericardiacophrenic artery accompanies the ( ).
Answer: C
It is a long slender branch of the internal thoracic artery running with the phrenic nerve between the pericardium and mediastinal pleura to the diaphragm.TMU Lecture 14 Slide 12
14Irritation of the central diaphragmatic pleura causes pain referred to the ( ).
Answer: D
Referred to the shoulder tip, because the phrenic nerve is C3–C5 and the supraclavicular nerves supplying shoulder skin are C3–C4.Gray's 4e p.150
15The posterior intercostal arteries of spaces 3–11 arise from the ( ).
Answer: A
Directly from the thoracic aorta. The upper two spaces are supplied by the superior intercostal artery from the costocervical trunk.Snell's 10e Ch.4
16Pleural aspiration is classically performed in the midaxillary line at the ( ).
Answer: B
The 8th or 9th space in the midaxillary line — below the lung edge (8th rib) but above the pleural limit (10th rib), so you enter the costodiaphragmatic recess without hitting lung or abdomen.TMU Lecture 14 Slide 17 · Snell's 10e Ch.5
17The internal intercostal muscle becomes membranous ( ).
Answer: C
Posteriorly, near the vertebral column. The external intercostal is the one that becomes membranous anteriorly, where the costal cartilages already connect the ribs.TMU Lecture 14 Slide 5
18Normal pleural cavity contents are ( ).
Answer: D
Only a thin film of serous fluid, enough to lubricate. (About 50 mL is the volume in the pericardial cavity — do not confuse them.)Gray's 4e p.150
19Which structure does NOT lie in an intercostal space?
Answer: A
The thoracic duct ascends in the posterior mediastinum, not in the chest wall. The other three are all components of the intercostal space.Gray's 4e p.136
20Lung tumours are often painless until late because ( ).
Answer: B
The lung and visceral pleura have only autonomic innervation and no somatic pain fibres. Pain begins when the tumour invades the parietal pleura or chest wall.Gray's 4e p.150 (clinical application)
1 Costodiaphragmatic recess — TMU 2021–22 · 3′+
The slit-like interval on each side where the costal pleura becomes continuous with the diaphragmatic pleura.
It is the lowest part of the pleural cavity and is not filled by the lung even in deep inspiration.
Clinical meaning: pleural fluid collects here first, so it is the site chosen for pleural aspiration and chest drain insertion — classically the 8th or 9th space in the midaxillary line.TMU Lecture 14 Slide 16 · Gray's 4e p.152
It is the lowest part of the pleural cavity and is not filled by the lung even in deep inspiration.
Clinical meaning: pleural fluid collects here first, so it is the site chosen for pleural aspiration and chest drain insertion — classically the 8th or 9th space in the midaxillary line.TMU Lecture 14 Slide 16 · Gray's 4e p.152
2 The four parts of the parietal pleura — 6′ · asked 2021–22+
1. Cupula (cervical) pleura — over the apex of the lung, 2–3 cm above the medial third of the clavicle.
2. Costal pleura — lines the inner surface of the chest wall.
3. Mediastinal pleura — lines the mediastinum; forms the pulmonary ligament below the lung root.
4. Diaphragmatic pleura — lines the upper surface of the diaphragm.TMU Lecture 14 Slide 15
2. Costal pleura — lines the inner surface of the chest wall.
3. Mediastinal pleura — lines the mediastinum; forms the pulmonary ligament below the lung root.
4. Diaphragmatic pleura — lines the upper surface of the diaphragm.TMU Lecture 14 Slide 15
3 Intercostal neurovascular bundle — 3′+
The intercostal vein, artery and nerve, lying in that order from above downwards in the costal groove on the lower border of the upper rib of each space.
The bundle lies in the plane between the internal and innermost intercostal muscles. A collateral branch of each runs along the upper border of the rib below.
Clinical: chest drains are inserted just above the upper border of the lower rib to avoid it.TMU Lecture 14 Slide 21 · TMU 2021–22 MCQ Q1
The bundle lies in the plane between the internal and innermost intercostal muscles. A collateral branch of each runs along the upper border of the rib below.
Clinical: chest drains are inserted just above the upper border of the lower rib to avoid it.TMU Lecture 14 Slide 21 · TMU 2021–22 MCQ Q1
4 Pulmonary ligament — 2′+
A double fold of mediastinal pleura hanging downward from the root of the lung, where the visceral pleura becomes continuous with the mediastinal parietal pleura.
It is redundant pleura that allows the structures of the lung root to move during respiration and permits distension of the pulmonary veins.TMU Lecture 14 Slide 15
It is redundant pleura that allows the structures of the lung root to move during respiration and permits distension of the pulmonary veins.TMU Lecture 14 Slide 15
5 Internal thoracic artery — 3′+
A branch of the first part of the subclavian artery, descending about 1 cm lateral to the sternal margin with two accompanying veins.
Branches: pericardiacophrenic artery (with the phrenic nerve) · anterior intercostal arteries (upper six spaces) · and its two terminal branches, the superior epigastric and musculophrenic arteries.
Clinical: the graft of choice for coronary artery bypass.TMU Lecture 14 Slide 13
Branches: pericardiacophrenic artery (with the phrenic nerve) · anterior intercostal arteries (upper six spaces) · and its two terminal branches, the superior epigastric and musculophrenic arteries.
Clinical: the graft of choice for coronary artery bypass.TMU Lecture 14 Slide 13
6 Surface projection of lung and pleura — 2′+
Lower border of the LUNG: 6th rib (midclavicular) · 8th rib (midaxillary) · 10th rib (paravertebral).
Lower border of the PLEURA: 8th rib · 10th rib · 12th rib.
The pleura is always two ribs lower than the lung; that two-rib gap is the costodiaphragmatic recess.TMU Lecture 14 Slide 17
Lower border of the PLEURA: 8th rib · 10th rib · 12th rib.
The pleura is always two ribs lower than the lung; that two-rib gap is the costodiaphragmatic recess.TMU Lecture 14 Slide 17
1
Draw and describe the structures passing through an intercostal space.
8′
Set as the drawing homework in TMU Lecture 14.
Layers, from outside inwards
- Skin and superficial fascia, with cutaneous branches of the intercostal nerve
- External intercostal — fibres posterosuperior → anteroinferior; membranous anteriorly; acts in inspiration
- Internal intercostal — fibres anterosuperior → posteroinferior; membranous posteriorly; acts in expiration
- Neurovascular bundle in the costal groove
- Innermost intercostal muscle
- Endothoracic fascia
- Parietal (costal) pleura
The neurovascular bundle
In the costal groove on the lower border of the upper rib, from above downwards: intercostal vein · intercostal artery · intercostal nerve (VAN), lying between the internal and innermost intercostal muscles. A collateral branch of each runs along the upper border of the rib below.
Blood supply
- Posterior intercostal arteries — from the thoracic aorta (spaces 3–11)
- Anterior intercostal arteries — from the internal thoracic artery (upper six spaces)
- Veins drain to the azygos system posteriorly and the internal thoracic veins anteriorly
Clinical application
A chest drain or aspirating needle is inserted immediately above the upper border of the rib below, to avoid the main bundle in the costal groove.
Marking guide: muscle layers with fibre directions 2 · VAN order 2 · plane of the bundle 1 · arterial supply 2 · clinical application 1.
2
Write down the four parts of the parietal pleura. What is the costodiaphragmatic recess and its clinical meaning?
6′
Real question — TMU 2021–22 final, Section III Q1.
The four parts of the parietal pleura
- Cupula (cervical) pleura — extends into the root of the neck over the apex of the lung, 2–3 cm above the medial third of the clavicle
- Costal pleura — lines the inner surface of the chest wall
- Mediastinal pleura — lines the mediastinum, and forms the pulmonary ligament below the lung root
- Diaphragmatic pleura — lines the upper surface of the diaphragm
The costodiaphragmatic recess
The slit-like interval where the costal pleura becomes continuous with the diaphragmatic pleura. It is a potential space of the pleural cavity which the lung does not occupy in quiet respiration — indeed it is not filled even in deep inspiration.
Clinical meaning
- It is the lowest part of the pleural cavity, so a pleural effusion or blood collects here first
- It is therefore the site chosen for pleural aspiration (thoracocentesis) and chest drain insertion — classically the 8th or 9th intercostal space in the midaxillary line
- The needle passes just above the upper border of the rib below to avoid the intercostal neurovascular bundle
Marking guide: four parts named 2 (½ each) · definition of the recess 2 · lowest point stated 1 · clinical use 1.
3
Describe the pleura and pleural cavity.
7′
Arrangement
A continuous serous membrane invaginated by the lung, like a fist pushed into a balloon.
- Visceral pleura — adherent to the lung surface, dipping into the fissures
- Parietal pleura — lining the walls of the cavity, in four named parts
- Pleural cavity — the potential space between them, containing a thin film of serous fluid
- The two become continuous at the root of the lung, hanging below it as the pulmonary ligament
Parts of the parietal pleura
Cupula (cervical) · costal · mediastinal · diaphragmatic.
Recesses
- Costodiaphragmatic recess — between costal and diaphragmatic pleura; the lowest part of the cavity
- Costomediastinal recess — anteriorly between costal and mediastinal pleura, most marked on the left at the cardiac notch
Nerve supply and its consequences
- Parietal pleura: intercostal nerves (costal and peripheral diaphragmatic parts) and the phrenic nerve (mediastinal and central diaphragmatic parts) — pain is sharp and well localised
- Visceral pleura: autonomic only — insensitive to pain
- Irritation of the central diaphragmatic pleura refers pain to the shoulder tip (C3–C5)
Marking guide: visceral/parietal/cavity 2 · four parts 1.5 · two recesses 1.5 · nerve supply 1 · referred shoulder pain 1.
4
Describe the internal thoracic artery and the blood supply of the thoracic wall.
6′
Internal thoracic artery
- A branch of the first part of the subclavian artery
- Descends about 1 cm lateral to the sternal margin, behind the costal cartilages, with two venae comitantes
- Ends in the 6th intercostal space by dividing into its two terminal branches
Branches
- Pericardiacophrenic artery — long and slender, accompanying the phrenic nerve to the diaphragm
- Anterior intercostal arteries — to the upper six intercostal spaces
- Superior epigastric artery — terminal, entering the rectus sheath
- Musculophrenic artery — terminal, running along the costal margin
The double supply of an intercostal space
Each space receives a posterior intercostal artery from the thoracic aorta behind and an anterior intercostal artery from the internal thoracic artery in front. They anastomose within the space.
Clinical relevance
- The internal thoracic artery is the graft of choice in coronary artery bypass, with far better long-term patency than a saphenous vein graft
- In coarctation of the aorta the anastomosis between the two systems enlarges to carry blood past the narrowing, eroding the ribs and producing rib notching on X-ray
Marking guide: origin and course 1.5 · four branches 2 · double supply of the space 1.5 · one clinical point 1.
5
Give the surface projections of the lungs and pleurae and explain their clinical use.
6′
Lower borders
| Lower border | Midclavicular line | Midaxillary line | Beside the vertebral column |
|---|---|---|---|
| Lung | 6th rib | 8th rib | 10th rib |
| Pleura | 8th rib | 10th rib | 12th rib |
The rule: the pleura is always two ribs lower than the lung. The apex of both rises 2–3 cm above the medial third of the clavicle.
Why the two-rib gap exists
It is the costodiaphragmatic recess — the part of the pleural cavity the lung does not occupy.
Clinical use
- Pleural aspiration / chest drain: midaxillary line, 8th or 9th intercostal space — inside the pleural cavity, below the lung edge, above the diaphragm. Going lower risks the liver on the right or the spleen on the left
- Apical injury: because the cupula rises into the neck, a stab wound above the clavicle or a subclavian line can cause a pneumothorax
- Knowing the lung border allows correct interpretation of percussion and breath sounds
Marking guide: lung borders 1.5 · pleural borders 1.5 · the two-rib rule 1 · apical extent 1 · one clinical application 1.