A chest x ray is a fast and painless imaging test that uses certain electromagnetic waves to create pictures of the structures in and around your chest. This test can help diagnose and monitor conditions such as pneumonia, heart failure, lung cancer, tuberculosis, sarcoidosis, and lung tissue scarring, called fibrosis

1. Chest Radiograph
Lobar & Segmental Anatomy of
Lung
AMIT JHA

2. CHEST INTRODUCTION
Technical Adequacy
In trying to determine if pathology is present in a chest radiograph
several factors have to be considered in the overall judgment of the
radiograph to determine if the visual findings are pathologic or in
part are related to the radiograph itself.
Factors to be considered on all chest x-rays include:
Inspiration
Penetration
Rotation
Angulation
Orientation

3. • Inspiration: The volume of air in the hemithorax
will affect the configuration of the heart with
question of cardiac enlargement with a shallow
level of inspiration. The vascular pattern in the
lung fields will be accentuated with a shallow
inspiration since the same amount of blood flow is
now distributed to a smaller volume of lung.
• The level of inspiration can be estimated by
counting ribs. Visualization of nine posterior ribs,
or seven anterior ribs on an upright PA radiograph
projecting above the diaphragm would indicate a
satisfactory inspiration.

4. Inspiration Expiration

5. Quality Control
Inspiration
– Should be able to count
9-10 posterior ribs
– Heart shadow should
not be hidden by the
diaphragm
1
2
3
4
5
6
7
8
9
10

6. 9-10 posterior ribs are showing
9
About 8 posterior ribs are showing
8
Poor inspiration can
crowd lung markings
producing pseudo-
airspace disease
With better inspiration, the
“disease process” at the
lung bases has cleared

7. • Penetration: Refers to adequate photons traversing
the patient to expose the radiograph. This is often
limited in patients of large size such that there is
poor visualization of structures in the lower lung
fields and in a retro-cardiac location. The lack of
penetration renders the area “whiter” than with an
adequate film and can simulate pneumonia or
effusion. In an ideal radiograph the thoracic spine
should be barely perceptual viewing through the
cardiac silhouette. The soft tissues at the shoulder
can also give an estimate of the relative degree of
penetration of the film.

8. Penetration
– Should see ribs
through the heart
– Barely see the spine
through the heart
– Should see
pulmonary vessels
nearly to the edges
of the lungs

9. Overpenetrated
Film
• Lung fields
darker than
normal—may
obscure subtle
pathologies
• See spine well
beyond the
diaphragms
• Inadequate lung
detail

10. Underpenetrated
Film
• Hemidiaphragms
are obscured
• Pulmonary
markings more
prominent than
they actually are

12. DID YOU SEE THE NODULE ON
THE PREVIOUS FILM?

13. • Angulation: With the patient in a more
lordotic projection the clavicles will project
superiorly relative to the upper thorax again
causing some distortion of the normal
mediastinal anatomy. With the lordotic
projection of the ribs assume a more horizontal
orientation. Occasionally a lordotic xray can
be obtained intentionally to better visualize
structures in the thoracic apex obscured by
overlying boney structures.

14. Angulation

15. Quality Control
Angulation
– Clavicle should lay
over 3rd
rib
1
2
3

16. Pitfall Due to Angulation
• A film which is apical lordotic (beam is angled up toward head) will have
an unusually shaped heart and the usually sharp border of the left
hemidiaphragm will be absent
Apical lordotic Same patient, not lordotic
A film which is apical lordotic (beam is angled up toward head) will have anA film which is apical lordotic (beam is angled up toward head) will have an
unusually shaped heart and the usually sharp border of the leftunusually shaped heart and the usually sharp border of the left
hemidiaphragm will be absenthemidiaphragm will be absent

17. • Rotation of the patient distorts mediastinal anatomy
and makes assessment of cardiac chambers and the
hilar structures especially difficult. Chest wall
tissue also contributes to increased density over the
lower lobe fields simulating disease. Rotation of the
radiograph is assessed by judging the position of the
clavicle heads and the thoracic spinous process.
Ideally the clavicle heads should be equidistant from
the spinous process.

18. RotationRotation
Medial ends of bilateralMedial ends of bilateral
clavicles are equidistantclavicles are equidistant
from the midline orfrom the midline or
vertebral bodiesvertebral bodies

20. DISTORTED MEDIASTINUM DUE
TO TORTOUS AORTA AND
ROTATION.

21. If spinous process appears closer to the right clavicle (red
arrow), the patient is rotated toward their own left side
If spinous process appears closer to the left clavicle (red arrow),
the patient is rotated toward their own right side

22. EXAMPLE OF
GOOD
INSPIRATION
PENETRATION
ROTATION
ORIENTATION
ANGULATION

23. Systematic review
• A-B-C-D-E-F-G-H
o A: Airway
o B: Bone
o C: CV
o D: Diaphragm
o E: Extra-pulmonary
o F: Lung field
o G: Gastric bubble
o H: Hilum/Hernia

24. Findings
• Soft tissue and
bony
structures
– Check for
• Symmetry
• Deformities
• Fractures
• Masses
• Calcifications
• Lytic lesions

25. Findings
• Mediastinum
– Check for
• Cardiomegaly
• Mediastinal
and Hilar
contours for
increase
densities or
deformities

26. Findings
• Diaphragms
– Check sharpness
of borders
– Right is normally
higher than left
– Check for free air,
gastric bubble,
pleural effusions

27. Findings
• The Lung Fields!
– To help you
determine
abnormalities and
their location…
• Use silhouettes
of other thoracic
structures
• Use fissures

30. Lobar anatomy

31. • Anatomy & projection
– General anatomy
– Lobar anatomy
• Fissures
– Def: Pleura surround by air
– 3 main (1 minor; 2 major)
– 3 accessory (Azygos; inferior & superior accessory)
– If fissure do not appear a thin line
- Pneumonia (Bulging)
- Atelectasis (Deviation)
- Pleural effusion (Pseudotumor)
– Segmental anatomy
• The sihouette sign
Normal Anatomy

32. Lung Fields: Fissures
• The fissures can also help you to determine
the boundaries of pathology
Major Oblique Fissure
Separates the LUL from the
LLL
Right Major Fissure
Separates the RUL/RML from
the RLL
Right Minor Fissure
Separates the RUL from the
RML

35. Lobar anatomy
1 2
1 2
3-4-5
3-45
3-4-6 6

37. • Lobar Anatomy—Right lung
• 􀂄 There are 3 lobes
• 􀂄R upper lobe (RUL)
• 􀂄R middle lobe (RML)
• 􀂄R lower lobe (RLL)
• 􀂄 The horizontal or minor fissure separates
• the upper and middle lobes.
• 􀂄 The major or oblique fissure separates the
• lower lobe from the upper and middle lobes.

38. The right upper lobe (RUL) occupies the upper 1/3 of the right lung. Posteriorly, the RUL is
adjacent to the first three to five ribs. Anteriorly, the RUL extends inferiorly as far as the 4th
right anterior rib

39. The right middle lobe is typically the smallest of the three, and appears triangular
in shape, being narrowest near the hilum

40. The right lower lobe is the largest of all three lobes, separated from the others by the major
fissure. Posteriorly, the RLL extend as far superiorly as the 6th thoracic vertebral body, and
extends inferiorly to the diaphragm. Review of the lateral plain film surprisingly shows the
superior extent of the RLL.

43. • SEGMENTAL ANATOMY
Right lung
RUL segments
􀂄 Apical-1
􀂄 Anterior-2
􀂄 Posterior-3

44. 1
1
2 2
3
3

45. • RML segments
• 􀂄 Lateral-4
• 􀂄 Medial-5

46. 4 4
5
5

47. 66

48. 7
97
9

49. 8 10
8 10

50. 1+2
3
3
1+2

51. 4
4
5
5

52. 7
+
8 10
9

53. 53
Silhouette sign
• Sign describes the observation that an intra-
thoracic lesion will obliterate borders of
shadows of similar radio-dense structures
that it contacts
• Example: right middle lobe pneumonia will
obliterate the right heart border

54. Silhouette sign
Normal
Pneumonia
(-) silhouette sign
(visible heart silhouette)
Pneumonia
(+) silhouette sign
(no heart silhouette)54

55. 55
Silhouette Sign
Example: Airspace disease may silhouette:
– right heart margin with right middle lobe pneumonia
– diaphragm with lower lobe pneumonia

56. Lung Fields: Using Structures /
Silhouettes
Silhouette / Structure Contact with Lung
Upper right heart
border/ascending aorta
Anterior segment of RUL
Right heart border RML (medial)
Upper left heart border Anterior segment of LUL
Left heart border Lingula (anterior)
Aortic knob
Apical portion of LUL
(posterior)
Anterior hemidiaphragms Lower lobes (anterior)

57. Lung Fields: Using Structures /
Silhouettes
Upper right heart
border /
ascending aorta
(anterior RUL)
Right heart border
(medial RML)
Anterior
hemidiaphragms
(anterior
lower lobes)
Upper left
heart border
(anterior
LUL)
Left heart
border
(lingula;
anterior)
Aortic knob
(Apical portion
of LUL )

58. Pulmonary edema
+ silhouette sign
58

59. 59
Pulmonary edema
+ silhouette sign

60. 60154 slides
Where is the Pneumonia?
60

61. 61

62. 62154 slides
Right Lower Lobe Pneumonia
Left
Right:
Partially seen
62

63. 63154 slides
Where is the pneumonia?
63

64. 64

65. 65154 slides
Oblique(major)
fissure
Horizontal (minor fissure)
65

66. 66154 slides
Right Middle Lobe Pneumonia
66

67. 67154 slides
Left Lower Lobe Pneumonia
67

72. PA view: RML consolidation and loss
of right heart silhouette
Lateral View: RML wedge shaped
consolidation

73. RUL infiltrate / consolidation, bordered by minor fissure inferiorly
Patchy LLL infiltrate that obscures the left hemidiaphragm; right and left
heart borders obscured
RUL and LLL pneumonia

74. Underpenetrated; possible nonspecific obscuring of left heart border;
mostly normal

75. RML consolidation that appears wedge shaped on
lateral view

76. RLL infiltrate / consolidation

77. Obscuring of the right and left heart
borders; infiltrate at the bases
Bilateral aspiration pneumonia

78. LUL pneumonia

79. • Most of the L heart border - lingular
segment of the LUL
• R heart border - RML

80. • Aortic knob
apical posterior
segment of LUL

81. THANK YOU

82. Project

83. • Anatomy dividing region
– SUPERIOR MEDIASTINUM
• Begins - root of the neck and
• Ends - line drawn T-4 vertebrae --- sternomandible junction.
– line skims the top of the aortic arch. T
– Mediastinum
• Begins - this line
• End- diaphragm
• Further divided into three regions
– Anterior
– Middle
– Posterior.
MEDIASTINUM

84. 1cm
4

86. Mediastinum
• Overall size and shape
• Trachea- position
• Margins
• SVC- Ascending aorta
• Right atrium
• Left subclavian artery- Aortic arch
• Main pulmonary artery
• Left antrium
• Left ventricle
• Lines and stripes
• Retrosternal clear space

87. I
II IV
I
II
III
Margins

88. Mediastinum
• Overall size and shape
• Trachea: position
• Margins
• Lines and stripes
• Paratracheal
• Paraspinal
• Paraesophageal (azygoesophageal)
• Paraaortic
• Retrosternal clear space

89. Edge of Superior vena cave (SVC)
• Seen PA(AP) view only
• Often only a portion
• Never bulge into the lung
with a convex border.

90. Right Pratracheal stripe

91. • Normal- < 5 mm,
usually 2-3 mm.
– Important marker for subtle adenopathy.
• Distal end - formed by azygous vein
– Distended vein, stripe > 1 cm.
• Medial margin -soft tissue interface /right mucosal surface of trachea.
• Outer margin -begins medial end of clavicle/formed by plural surface of
right upper lobe (RUL).
• Normal structures in soft tissue density between air trachea and the RUL
– Right wall of the trachea
– Nerves
– Fat
– Lymph nodes
– Pleura of the RUL.
• Azygous vein - anteriorly to empty into the posterior surface of the SVC.
Right Pratracheal stripe

92. Right paratracheal
stripe(TOMOGRAM )

93. CT of Paratracheal stripe
1. Asending aorta
2. Azygous vein
3. Esophagus
4. Desending aorta
5. Pulmonary trunk

94. Left Subclavian stripe
• Width- normal 1.0-1.5 cm.
• Inner margin-
Air mucosal interface
-mucosal surface of the
trachea,
• Outer margin interface -
Medial aspect of left upper
lobe
• Upper- outer edge
Level of the clavicle and will
be able to follow it
• End-
Bulge of the aortic arch.

95. Paraspinal stripe

96. • Sometimes(+) on the frontal view
• Plural edge parallel to the lateral margins of the
vertebral bodies.
• Edge > millimeters beyond the vertebral bodies
• Should not be lumpy or bulging.

97. Pleural mediastinal interface
1. Superior Vena Cava
2. Right Paratracheal
Stripe
3. Left Subclavian Stripe

98. Azygoesophageal line or
Paraesophageal line

100. Lateral view of tracheal wall
• Posterior tracheal
< 4mm

101. • Overall size/ shape on PA & lateral views
– Decide if it is normal & age.
• Look for
– Obvious masses
– Calcifications
– Double check for foreign projects
• Tubes
• Electrical leads
• Pacemaker
• Artificial valves
MEDIASTINUM

102. 1. Trachea
2. Right Ventricle
3. Left Ventricle
4. Left Atrium
5. Right Pulmonary
Artery
Lateral view of heart

103. Pulmonary arteries, Lateral view
1. Trachea
2. Right Ventricle
3. Left Ventricle
4. Region of left Atrium
5. Right Pulmonary
Artery
6. Left Pulmonary Artery
6