Respiratory Module Anatomy by Radiology
• Welcome to this PowerPoint presentation on
anatomy seen radiologically.
• There are normal and abnormal views of the
nasal cavity and sinuses, and of the thorax.
• Plain X-ray, CT and MRI have been used.
• Study the images and answer the questions
before moving to answers on the next slide (your
learning and retention will be much better).
• Always cross-reference and integrate with other
learning experiences and resources (Phase I
lectures and the “Read After” anatomy guide).
Nasal Cavity and Sinuses
This CT is like studying a parasagittal section of a head in
the Dissecting Room, but the sinuses are visible.
Frontal
Ethmoid
Sphenoid
Middle concha
Inferior concha
Nasal Cavity and Sinuses
• Where do the sinuses open?
• What opens into the inferior meatus?
Frontal
Ethmoid
Sphenoid
Middle concha
Inferior concha
Nasal Cavity and Sinuses
• The sphenoid sinus opens into the spheno-ethmoidal
recess above the superior meatus. The frontal,
ethmoidal and maxillary open into the middle meatus.
• The nasolacrimal duct drains lacrimal fluid from the
conjunctival sac to the inferior meatus of the nasal cavity.
• Look at the next two slides showing horizontal sections
of the maxillary, and then ethmoid sinuses, just to
appreciate their relationships to each other and to the
nasal cavity.
Nasal septum 
Maxillary sinus 
Ethmoid air cells 
Sphenoid air cells 
Mastoid air cells 
Nasal Cavity and Sinuses
• Note the close proximity of the orbits, and the brain in
the cranial cavity, to the nasal cavity.
• To what do the arrows point?
Brain
?
Orbit
?
?
?
?
Nasal Cavity and Sinuses
Brain
Ethmoid Sinus
Middle
Concha
Orbit
Maxillary
Sinus
Septum
Inferior Concha
Nasal Cavity and Sinuses
• The nasal conchae create a large surface for carrying
out nasal function.
• But the nasal passages are narrow and easily
obstructed.
Position of Maxillary
Sinus Opening
Nasal Cavity and Sinuses
• The nasal cavity and sinuses are lined by a vascular
mucous membrane with pseudostratified, ciliated,
columnar epithelial cells to slow, warm, filter and
humidify the inhaled air.
• Ciliary action empties the sinuses.
• The maxillary sinus opening is high in the medial wall of
the sinus and anything affecting the ciliary action, or
narrowing the passageways may prevent proper
emptying.
Sinusitis
• The right maxillary and ethmoid sinuses are obstructed.
• The frontal sinuses are enlarged.
Frontal
Maxillary
Sinusitis
• Thickened mucous membrane in maxillary sinuses.
• Deviated septum.
Septum
Thorax Cross Section
Identify the numbers 1 to 10
1
2
10
9
3
8
7
4
6
5
1 Ascending aorta; 2 Pulmonary trunk (artery); 3 Left PA; 4
Left bronchus; 5 Descending aorta; 6 Oesophagus; 7 Azygos
vein; 8 Right bronchus;
9 Right PA; 10 Superior vena cava.
1
2
10
9
3
8
4
7
6
5
Thorax
• This is a contrast enhanced CT. As the injection is
intravenous, the SVC is brighter.
• Identify 1, 2 and the arrows.
• You are looking from the feet upwards.
Sternum
?
?
1
2
Vertebra
Thorax
• 1 is trachea, 2 is oesophagus.
• What vertebral level is this?
SVC
Aortic Arch
1
2
2
Thorax
• The aortic arch is in the superior mediastinum opposite
T4.
• The white spots in the lungs are contrast in pulmonary
vessels that are cut in section as they radiate into the
lungs.
• What would be visible at a higher and at a lower level?
Thorax T3
The trachea and oesophagus are still visible. The left
and right brachiocephalic veins join to form the SVC.
The aortic arch has given the brachiocephalic trunk (1),
left common carotid, with vagus just lateral (2) and left
subclavian (3)
SVC
1
2
3
T3
Thorax T4/5
•
•
•
•
1 and 2: Ascending and descending aorta.
3: Tracheal bifurcation.
4: SVC.
What lies behind the bifurcating trachea?
1
4
3
2
Thorax T4/5
• The oesophagus on the left with the azygos vein just to
the right of it. The vein can be followed to the SVC. 5 is
the pulmonary trunk.
1
4
5
3
2
Azygos
vein
Oesophagus
Thorax T5/6
1, 2 and 4 are as before but 3 is now the left main
bronchus. Look at 5, the pulmonary artery dividing.
Remember for next slide!
Left pulmonary artery
1
5
Right pulmonary
artery
Oesophagus
4
3
2
Azygos vein
Thorax Pulmonary Embolus
Compare this slide and the previous one. Note the “filling
defects” in the contrast at the bifurcation of the pulmonary
artery and at the bifurcation of the left pulmonary artery:
thrombotic emboli. What is the likely site of origin of the
thrombus, and its route to the lung? What is visible
posteriorly?
Asc. Ao.
Embolus in PA
SVC
Embolus in left PA
Right bronchus
Left bronchus
?
Thorax Pulmonary Embolus
• The thrombus originated in a deep vein in the lower limb,
e.g. the posterior tibial.
• It then moved to: popliteal, femoral, external iliac,
common iliac, inferior vena cava, right atrium, right
ventricle, pulmonary trunk (artery) and left pulmonary
artery.
• Posteriorly on the left, there is a little lung consolidation
and pleural effusion following the embolus.
• The next slide is a case presentation:
Male (63) CT Pulmonary Angiogram after acute massive pulmonary embolus.
Occluded Rt. main P. artery (arrow) and filling defect Lt. P. artery (arrow).
Presented with: acute dyspnoea, hypoxia, low BP, acute Rt. heart strain on ECG
No clot seen in IVC or iliofemoral veins on CT Abdo/Pelvis
Negative coagulopathy and auto-antibody screens.
Treated with thrombolysis and low molecular weight heparin, then warfarin.


Thorax Heart at T 7 or 8
Identify the 4 chambers of the heart seen here in cross-section.
?
?
?
?
Thorax Heart at T 7 or 8
Right
ventricle
Right atrium
Left ventricle
Left atrium
Normal Chest Radiograph
1 Clavicle
2 Trachea, centrally
positioned
3 Heart shadow
4 Vertebral column
5 Gas in fundus of
stomach
Note that the lung
vascular markings fill
the thoracic cavity
1
2
3
4
5
Right Pneumothorax
The arrows point to the
edge of the right lung.
There is air outside it, within
the pleural cavity. The edge
is barely visible, but there
are no vascular markings
lateral to the arrows.
The trachea is still central
but may shift away from the
side of the lesion in a
tension pneumothorax.
Here is another,
very obvious
right-sided
pneumothorax,
note how the
lung markings
stop and the
right lung only
fills about half of
the right thoracic
cage.
Lung Tumour
The arrow
indicates a mass
near the left lung
hilum.
Why might this
condition present
with hoarseness
of the voice?
Lung Tumour
• The mass is seen here, compressing the left pulmonary
artery.
• The mass could compress the left vagus or recurrent
laryngeal nerve.
A Rarity!
Look for the
expected aortic
knuckle (arch) on
the left. It is not
there.
The arrow shows
this patient has a
right-sided aortic
arch.
Tumour, ball valve affect
The arrow shows a
tumour compressing
the left main
bronchus. It acts like a
valve allowing air in
but not out, as would
an inhaled foreign
body in the bronchus.
Consequently the left
lung is hyperinflated.
It looks more
radiolucent than the
right lung and the
vascular markings are
reduced.
Pneumonia
The arrow shows
the consolidation
of pneumonia.
1 is the upper
part of the right
lobe of the liver,
bulging upward
under the
diaphragm.
1
The End
Those 34 slides complete the radiological revue of the
anatomy of the Respiratory System and Thorax. A
knowledge of topographical and surface anatomy is
essential to understand the images.
This presentation was created with the support and
guidance of Dr Tom Taylor, consultant radiologist,
Ninewells Hospital, who provided the radiographic
images.