Normal Lung Anatomy Flashcards
1
Q
The right paratracheal stripe should not exceed how many mm in width?
A
Should not exceed 4 mm in width
2
Q
The tracheoesophageal stripe should measure less than how many mm?
A
Less the 5 mm
3
Q
Thickening of the tracheoesophageal stripe is commonly seen in what disease?
A
Esophageal carcinoma
4
Q
The right mainstem bronchus is considerably shorter than the left.
What are their average mean length?
A
Right = 2.2 cm Left= 5 cm
5
Q
The airway just before the first respiratory bronchioles is known as?
A
Terminal bronchiole
6
Q
It is the smallest bronchiole without respiratory exchange structure.
A
Terminal bronchiole
7
Q
The inferior pulmonary ligament is a sheet of connective tissue that extends from what structures?
A
Extends from the hilum superiorly to a level at or just above the hemidiaphragm
8
Q
What comprises the inferior pulmonary ligaments?
A
It comprises fused visceral and parietal pleura and binds the lower lobe to the mediastinum and runs along side the esophagus
9
Q
The inferior pulmonary ligament contains what structures?
A
Contains the inferior pulmonary vein superiorly and a variable number of lymph nodes
10
Q
What comprises the azygous fissure?
A
Composed of 4 layers (2 visceral and 2 parietal pleura) and represents invagination of the right apical pleura by the azygous vein, which has incompletely migrated to its normal position at the right tracheobronchial angle.
11
Q
What is the significance of the azygous fissure?
A
Its ability to limit the spread of the apical segment consolidation to the azygous lobe and in excluding pneumothorax from the apical portion of the pleural space.
12
Q
It is the portion of apical segment delineated by the azygous fissure.
A
Azygous lobe
13
Q
The trachea is approximately how many cm long in adults?
A
12 cm long
14
Q
It is the narrowing of the coronal diameter producing a coronal-to- sagittal ratio of <0.6
A
Saber sheath trachea
15
Q
The major and minor fissure are best visualised on what radiographic view?
A
Lateral radiographs
16
Q
The minor fissure projects at the level of what rib?
A
4th rib
17
Q
Most common accessory fissure?
A
Inferior accessory fissure (10 to 20% of individuals)
18
Q
What does the inferior accessory fissure separate?
A
It separates the medial basal from the remaining basal segments of the lower lobe
It is often incomplete
19
Q
The inferior accessory fissure has been misidentified as what structure?
A
Inferior pulmonary ligament
20
Q
What structure can help identify the inferior accessory fissure?
A
A small triangle of extrapleural fat, seen at its point of insertion of the diaphragm
21
Q
This represent invaginations of the visceral pleura deep into the substance of the lungs.
A
Interlobar pulmonary fissures
22
Q
Incomplete fissures has important consequences regarding what processes?
A
Interlobar spread of parenchyma consolidation, collateral air drift in patients with lobar bronchial obstruction, and appearance of pleural effusion in the supine patient
23
Q
This fissure is complete in about 25% of individuals but fuses with the RUL in about 50% of cases.
A
Minor fissure
24
Q
The left major fissure is similar to the right major fissure, with fusion along what aspect in approximately 35% of individuals?
A
Posterior aspect
25
The superior accessory fissure separates what segments?
It separates the superior segment from the basal segments of the lower lobe.
26
The left minor fissure seperates what segment?
It separates the lingual from the remaining portions of the upper lobe.
27
Th tethering effect of the inferior pulmonary ligament on the lower lobe accounts for the medial location and triangular appearance of what disease process?
Lower lobe collapse
28
It is a linear structure seen on CT near the inferior pulmonary ligament extending into the lung from the mediastinal pleura.
It has been mistaken for the inferior pulmonary ligament.
Sublobar septum
29
What ligament is a triangular density extending toward the lung that is seen along the posterior aspect of the right heart border on lung window on chest CT?
Pericardiophrenic ligament
30
This structure represents a reflection of pleura over the inferior portion of the phrenic nerve and pericardiophrenic vessels.
Pericardiophrenic ligament
31
How can you distinguished the pericardiophrenic ligament from the sublobar septum?
By its more anterior location and its characteristic ramifications as branches of the nerve and vessel reflect over the diaphragm
32
What structure arises from the right ventricle at approximately 1-o’clock position relative to the ascending aorta?
Pulmonary artery
33
What artery is a direct continuation of the main pulmonary artery?
Left pulmonary artery
34
What pulmonary artery branches just below the carina, with an angle close to 90 degrees?
Right pulmonary artery
35
The right pulmonary artery divides within what structure?
Within the pericardium into the truncus anterior and interlobar arteries
36
What are the primary nutrient vessels of the lungs?
Bronchial arteries
37
Where does bronchial arteries usually arise?
From the proximal descending thoracic aorta at the level of the carina but may show significant variability.
38
How many bronchial arteries in right lung and in the left lung?
One right-sided and two left-sided arteries
39
Where does the right bronchial artery usually arise?
Usually arises from the posterolateral wall of the aorta in common with an intercostal artery as an intercostobronchial trunk
40
Where does the left bronchial arteries arise?
Left bronchial arteries arise individually from the anterolateral aorta or, rarely, from an intercostal artery
41
Approximately two-thirds of the blood from the bronchial arterial system returns to the pulmonary venous system via what veins?
Bronchial veins (a small right-to-left shunt)
42
Where does the pulmonary veins arise?
Within the interlobular septa from the alveolar and visceral pleural capillaries
43
The pulmonary veins may number from how many?
Three to eight
44
This lymphatic pathway form a network over the surface of the lung that roughly parallels the margins of the secondary lobules.
The visceral pleural lymphatic
45
What lymphatic pathways communicate via a obliquely oriented lymphatic located within the central region of the lung?
Perivenous and bronchoarterial lymphatics
46
Periveneous lymphatics and their surrounding connective tissue, when distended by fluid, account for the radiographic appearance of what?
Kerley A lines
47
It is the scaffolding of the lung and as such provides support for the airways and pulmonary vessels.
Pulmonary interstitium
48
It is the interstitial compartment that extends from the mediastinum and envelopes the bronchovascular bundles.
Axial interstitium
49
The axial fiber system of the interstitium continues distally as what?
The centrilobular interstitium along with the arteriolar, capillaries, and bronchioles to provide support for the air-exchanging portions of the lung
50
What are the parts of the peripheral interstitium?
The subpleural interstitium and interlobular septa
51
What divides the secondary pulmonary lobules?
Peripheral interstitium
52
Pulmonary veins and lymphatics lie within what interstitium?
Peripheral interstitium
53
A thin network of fibers that bridges the gap between the centrilobular and peripheral compartments
Intralobular interstitium
54
Edema involving the axial interstitium is recognized radiographically as what?
Peribronchial cuffing
55
Edema of the peripheral and subpleural interstitium accounts for what radiographic finding?
Kerry B lines (or interlobular lines on HRCT) and “thickened” fissures on chest radiograph
56
The lung-lung interfaces as seen on frontal radiographs relate directly to the space available in three regions viewed on the lateral film. What are these spaces?
The retrosternal space, the retrotracheal triangle, and the retrocardiac space
57
What airspace reflects contacts of the anterosuperior aspect of the upper lobes?
Retrosternal airspace
58
The anterior junction line often disappears in what situations?
After sternotomy, or when abundant anterior mediastinal fat precludes retrosternal contact of the upper lobes
59
This is a radiolucent region representing contact of the posterosuperior portions of the upper lobes.
Retrotracheal triangle
60
If the retrotracheal space available is small, only what interface will be visualized on the PA view?
Only a right paraesophageal interface is visualized
61
If the retrotracheal space is large, what line will be seen?
Posterior junction line
62
The azygoesophageal recess of the RLL can abut the preaortic recess of the LLL to produce an inferior posterior junction line. If what lung-lung interface is large?
Retrocardiac space
63
Thickening or nodularity of the paratracheal stripe is seen abnormalities of the tissues comprising the strip, including what disease processes?
Tracheal tumors, paratracheal lymph node enlargement, and right pleural effusion
64
What structure separates the right paraesophageal from the upper azygos esophageal space?
The arch of the azygos vein
65
What manoeuvres will increase the azygos venous diameter?
Supine positioning and Muller manoeuver (forced inspiration against closed glottis)
66
A diameter of >10 mm on PA radiograph of the azygos vein will raise the possibility of what processes?
Mass, adenopathy, or dilatation of the azygos vein
67
Dilation of the azygos vein may be seen in what situations?
Right heart failure, obstruction of venous return to the heart, or congenital venous anomaly such as azygos continuation of the inferior vena cava
68
Convexity of the superior third of the azygoesophageal interface should suggest what pathology?
Subcarinal lymph node enlargement or a mass
69
Convexity of the middle third of the azygoesophageal recess usually results from what situations?
Result of the confluence of right pulmonary veins or the right border of the left atrium
Left atrial dilatation will enlarge and laterally displace this interface, producing a double-density interface composed of the right lateral borders of both the right and left atria
70
Convexity of the inferior third of the azygoesophageal recess is commonly due to pathology?
Sliding hiatal hernia
Occasionally, a tortuous descending aorta or enlarged paraesophageal lymph nodes can cause this recess to be convex to the right in its lower third
71
What interface is a straight, vertical interface extending the length of the right hemithorax and represents contact of the right lung with small amount of tissue lateral to the thoracic spine?
Paraspinal interface
72
The inferior vena cabal interface is best visualized on what radiographic view?
Lateral radiographs
73
It is unusual for the LUL to interface with the left lateral wall of the trachea to form the left paratracheal stripe. Why?
Because the subclavian artery and adjacent fat usually intervene
74
This represents the superior intercostal vein as it arches anteriorly from its spinal position around the aortic arch to drain into the posterior aspect of the left inominate vein.
Aortic nipple
75
In approximately 5% of individuals, the left superior intercostal vein may be seen on frontal radiographs as a rounded or triangular opacity that focally indents the lung immediately superolateral to the aortic arch. What is this density termed?
Aortic nipple
76
The aortic nipple normally measures how many mm?
<5 mm
May enlarge with elevation of right atrial pressure or with congenital or acquired obstruction of venous return to the right heart.
77
Immediately inferior to the aortic arch, the LUL contacts to the mediastinum to produce what interface?
Aortopulmomary window interface
78
Concavity of the AP window interface is seen on what situations?
While lateral convexity would suggest what pathology?
Concavity = Tortuous aorta, emphysema, congenital absence of the pericardium
Convexity = Mass or lymph node enlargement
79
Immediately inferior to the aortopulmomary window is what structure?
Left lateral border of the main pulmonary artery
80
Enlargement of the main pulmonary artery is seen in what circumstances?
Idiopathic condition in young women, as a result of poststenotic dilatation in valvular pulmonic stenosis, or in conditions where there is increased flow or pressure in the pulmonary arterial system, such as left-to-right intracardiac shunts.
81
What interface is seen in small percentage of normal individuals as a reflection of the LLL with the esophagus anterior to the descending aorta, extending vertically from the undersurface of the aortic knob a variable distance toward the diaphragm?
Preaortic recess interface
82
What interface is usually etched in black? (Negative Mach effect)
Preaortic recess interface
83
What interface represents the reflection of the left lung off the paraspinal soft tissues, which largely consist of fat but also contain the sympathetic chain, proximal intercostal vessels, intercostal lymph nodes, and hemyazygos and accessory hemiazygos veins?
Left paraspinal interface
84
What interface is etched in white? (Positive Mach effect)
Left paraspinal interface
85
What diseases can cause lateral displacement of the left paraspinal interface?
Neurogenic tumors, hematoma, paraspinal abscess, lipomatosis, and medial pleural effusion
86
What structure forms a concave interface immediately below the main pulmonary artery?
Left atrial appendage
87
Straightening or convexity of the left atrial appendage interface is commonly seen in what cases?
Rheumatic mitral valve disease but may be seen in patients with left atrial enlargement of any cause
88
This structure may create a focal bulge in the left cardiac contour that obscures the heart border at the left cardiophrenic angle.
Fat adjacent to the cardiac apex or epipericardial fat
89
The epipericardial fat pad is most often seen in what patients?
Obese patients and this on corticosteroids
A typical appearance on the lateral radiograph is usually diagnostic; CT is helpful in equivocal cases
90
On frontal radiographs exposed in deep inspiration, the apex of the right hemidiaphragm typically lies at the level of what anterior rib?
Level of the sixth anterior rib, approximately one-half interspace above the apex of the left hemidiaphragm
91
Focal bulges in the diaphragmatic contour are usually a result of what pathology?
Acquired diaphragmatic eventration (thinning)
92
What is the Raider triangle?
The retrotracheal triangle
93
Borders of the retrotracheal triangle
Posterior border of the trachea/esophagus
Anterior border of the spine
Top of the aortic arch
94
Abnormal opacities in the retrotracheal triangle is seen in what disease?
Masses and air-space disease near the spices, retrotracheal masses (e.g., aberrant subclavian artery or posterior thyroid goiter), or esophageal masses
95
The impression on the anterior surface of the lingual is termed what.
Cardiac incisura
Should not be mistaken for a mass
96
The anterior pericardium can be identified separately from the myocardium in 20% of subjects. This thin line represents the pericardial layers between the epicardial and pericardial fat.
Nodularity or thickness of greater than how many mm would suggests disease or effusion?
>2.0 mm
