Normal structures visible
1. Tracheal air column.
3. First rib.
4. Peripheral lung fields have no markings except:
5. The minor fissure.
6. Top of the R diaphragm is usually between the
anterior 6th & 7th ribs, and overlying the
posterior 10th & 11th ribs.
7. Left diaphragm is lower (in 90-95%) by roughly
half an interspace.
8. Inferior margins of the posterior ribs.
9. Anterior mediastinal line.
10. Superior vena cava.
11. Azygos vein.
12. Right descending pulmonary artery.
13. Pulmonary arteries and veins.
14. Right atrium.
15. Inferior vena cava.
16. Aortic arch.
17. Left pulmonary artery.
18. Border of the left ventricle.
19. Descending aorta.
20. Fat density lines in the intermuscular fascial
Chest radiograph with
Light blue: right and
left paraspinal stripes.
anterior junction line
complex. Pink: left
border. Light green:
junction line. Dark
Lobes and Fissures
Left Lateral View Right Lateral View
LT. HEMI DIAPHRAGM
NORMAL CHEST ANATOMY
LATERAL CHEST XRAY
1. A line is drawn from
anterior surface of the
body of 6th thoracic
through the apex of the
heart up to anterior
lower most part of
2. Another straight line is
drawn from anterior
surface of the body of T-
6 vertebrae to the
On a normal lateral view the contours of the
heart are visible and the IVC is seen entering
the right atrium.
The retrosternal space should be radiolucent,
since it only contains air. Any radiopacity in
this area is suspecctive of a process in the
anterior mediastinum or upper lobes of the
As you go from superior to inferior over the
vertebral bodies they should get darker,
because usually there will be less soft tissue
and more radiolucent lung tissue (red arrow).
If this is not the case, look carefully for
pathology in the lower lobes.
The contours of the left and right
diaphragm should be visible.
The right diaphragm should be visible
all the way to the anterior chest wall
Actually we see the interface between
the air in the lungs and the soft tissue
structures in the abdomen.
The left diaphragm can only be seen to
a point where it borders the heart
Here the interface is lost, since the
heart has the same density as the
structures below the diaphragm.
The left main pulmonary artery (in purple)
passes over the left main bronchus and is higher
than the right pulmonary artery (in blue) which
passes in front of the right main bronchus.
In patients with a pectus excavatum the right heart border can be ill-defined, but this is normal.
It produces a silhouette sign and thus simulating a consolidation or atelectasis of the right middle
The lateral view is helpful in such cases.
Pectus excavatum is a congenital deformity of the ribs and the sternum producing a concave
appearance of the anterior chest wall.
Vena azygos lobe
A common normal variant is the azygos lobe.
The azygos lobe is created when a laterally displaced azygos vein makes a
deep fissure in the upper part of the lung.
On a chest film it is seen as a fine line that crosses the apex of the right lung.
Here another patient with an azygos lobe.
The azygos vein is seen as a thick structure within the azygos
In some patients an extra joint is seen in the anterior part of the
first rib at the point where the bone meets the calcified
cartilaginous part (arrow).
This may simulate a lung mass.
• Role of CT
– Main further investigation
for most CXR abnormality
(eg nodule/mass) or to
exclude disease with
– Main investigation for
certain scenarios (PE,
depending on clinical
• Helical/spiral versus high
– Renal failure
The secondary lobule is the basic anatomic unit of pulmonary structure and function. It is the
smallest lung unit that is surrounded by connective tissue septa. The secondary lobule is
supplied by a small bronchiole (terminal bronchiole) in the center, that is paralleled by the
Pulmonary veins and lymphatics run in the periphery of the lobule within the interlobular septa.
Centrilobular area is the central part of the secondary
Perilymphatic area is the peripheral part of the secondary
coronal view of
• Multiple planes
• No radiation
• Common Indication
– Pancoast tumour
– Brachial plexus
– Vascular (aorta)
• Usually targeted
Indications for MRI
•A chest MRI provides detailed pictures of tissues within the chest area.
•A chest MRI may be done for the following reasons:
•As an alternative to angiography, or to avoid repeated exposure to radiation
•Clarify findings from previous x-rays or CT scans
•Diagnose abnormal growths in the chest
•Evaluate blood flow
•Show lymph nodes and blood vessels
•Show the structures of the chest from multiple angles
•See if cancer in the chest has spread to other areas of the body - this is called
staging; staging helps guide future treatment and follow-up and gives you
some idea of what to expect in the future
•Tell the difference between tumors and normal tissue
female. MR angiography
normal pulmonary artery
artery main stem (black
arrow), right pulmonary
artery (white arrow) and
left pulmonary artery
the 3D reconstruction of the MRA image (1) allows the visualization of the entire pulmonary vasculature
identifying the subsegmental pulmonary arteries.
Dynamic contrast-enhanced MRA image in the oblique axial plane (2, 3, 4) allow the evaluation of pulmonary
circulation, including perfusion of the lung fields,
which is homogeneous and symmetric.
1: Right lung 2:Left lung
3:Cardiac silhouette 4.Mediastinum