This document provides an overview of the radiological anatomy of the tracheobronchial tree and techniques for demonstrating it. It begins with discussing the gross anatomy of the trachea and bronchi, their relations, blood supply and divisions. It then covers their appearance on various imaging modalities like plain radiography, CT, MRI, radionuclide scans and ultrasound. The techniques used for obtaining images with these different modalities are also described.

1. Radiological Anatomy of The
Tracheobronchial Tree And The
Techniques Of Its Demonstration
.
Dr.Mohammed Lawan (MBBS,FWACS)
Department of Radiology,
University of Maiduguri.
14th October, 2021.

2. OUTLINE
INTRODUCTION.
GROSS ANATOMY.
RADIOLOGIC ANATOMY.
Plain chest radiograph.
Bronchography
CT scan.
MRI.
Radionuclide scan.
Ultrasound scan.
TECHNIQUE OF ITS
DEMONSTRATION.
SUMMARY

3. GROSS ANATOMY
EMBRYOLOGY

4. Expand laterally and caudally into a
space known as primitive pleural
cavity.

5. INTRODUCTION
 The trachea-bronchial tree constitutes the
airway through which air enters & leaves the
lungs during respiration. It comprises of the
trachea & the bronchi.
 The trachea begins at the lower border of the
cricoid cartilage at the level of C6 vertebra.
 It extends to the carina at the level of the
sternal angle. It consist of the cervical and
thoracic part.
 It is 15cm long and 2cm in diameter and is
made up of 15-20 incomplete rings of cartilage
that are bridged posteriorly by the trachealis
muscle.
6/19/2023 5

6.  The main bronchus begins at the carina,
that is the anteroposterior ridge at the
junction of the main bronchi.
 It lies at T5 vertebral level i.e the sternal
angle.
 The carinal angle measures
approximately 65° - that is, 25° to the
right of the midline and 40° to the left.
 This angle is slightly larger in children.
 The right main bronchus (eparterial
bronchus) lies at 250 to the median
plane.
6/19/2023 6

7.  It is 2.5cm long and 1.5cm wide.
 It is thus wider, shorter and more
vertical than the left main bronchus.
 The left main bronchus ( hyparterial
bronchus) lies 400 to the median
plane.
 It is 5cm long and 1.2 cm in diameter.
6/19/2023 7

8. RELATION OF TRACHEA IN THE NECK

9. .POSTERIOLY.
Oesophagus- separate it from the vertebral
column.
Recurrent laryngeal nerve.

10. ON EACH SIDES.
Lobe of thyroid gland.
Common carotid artery.

11. RELATION OF TRACHEA IN
THE THORAX
ANTERIOLY(from before backward)
Manubrum sterni.
Remain of thymus gland.
Left brachiocephalic vein.
Arch of aorta together with origin of the
brachiocephalic and left common carotid arteries.
POSTERIOLY.
Oesophagus.
Left recurrent laryngeal nerve.
ON THE RIGHT SIDE.
Right vagus nerve.
Upper part of brachiocephalic artery.
Arch of vena azygous.
Right pleura and lung.

12. ON THE LEFT SIDE.
Left subclavian and left common carotid.
.
BLOOD SUPPLY OF TRACHEA
UPPER TRACHEA:-
Inferior thyroid artery.
LOWER TRACHEA:-
Branches of brachial artery.
VENOUS DRAINAGE:-
Inferior thyroid venous plexus.

13. ANATOMY OF THE
BRONCHI.
CARINA
Is the AP ridge at the junction of the
main bronchi.
It lies at T5 and at the level of sternal
angle.
The carinal angle measures 65º (25º
to the right and 40º to the left).
The carinal angle increase by 10-15%
in recumbency.

14. RIGHT MAIN BRONCHUS
Lies about 25º to the median plane.
2.5 cm long and 1.5 cm wide.
Wider shorter and more in line with
trachea.
Azygus vein arches above it origin to
enter the SVC.
Divide before reaching the hilum of
the right lung

15. RELATIONS.
ANTERIOLY.
Superior vena cava.
Right pulmonary artery.
POSTERIOLY.
Azygous vein.
SUPERIORLY.
Arch of azygous vein.
Bronchus of the upper lobe arises almost
immediately after tracheal bifurcation.
Continous as bronchi intermedius.
Middle lobe bronchus has medial and
lateral divisions.
Apical segment bronchus of the lower
lobes
comes off opposite the bronchus to the
middle lobe.

16. The lower lobe bronchus divide into five
segmental bronchi- apical, posterior, lateral,
anterior and medial.
LEFT MAIN BRONCHUS.
Lies at 40º to the median plane.
5 cm long and 1.2 cm in diameter.
Divides into upper and lower lobe bronchi
within the lung.
Upper lobe division are similar to the right.
Lingula bronchus comes off the upper lobe
bronchus and has superior and inferior
divisions.
Lower lobe bronchus has apical, lateral,
anterior and posterior basal but has no
medial basal

17. RELATIONS.
ANTERIORLY.
Pulmonary trunk.
POSTERIORLY.
Oesophagus.
Decending aorta.
SUPERIORLY.
Aortic arch.
Pulmonary artery.
ARTERIAL SUPPLY.
Bronchial artery, branch of thoracic
aorta.
Bronchial veins drain on the right to the
azygous system and on the left to the
hemiazygous system.

18. BRONCHOPULMONARY SEGMENT
Each lobe is divided into
bronchopulmonary segment. Each of is
supplied by segmental bronchus, artery
and vein.
Each segment takes it title from that of its
supplying bronchus.
RIGHT MAIN BRONCHUS.
Is shorter, wider and steeper than the left.
Bifurcate earlier into two main branches- one
above and the other below the pulmonary
artery known as the upper lobe bronchus and
the bronchus intermedius respectively.
The bronchus intermedius thereafter
subdivided into middle lobe bronchus and the
lower lobe bronchus.

19. RIGHT UPPER LOBE BRONCHUS- Has 3
main branches
Apical branch.
Posterior branch.
Anterior branch.
 RIGHT MIDDLE LOBE
BRONCHUS- Has 2
main branches.
Medial branch.
Lateral branch.
 RIGHT LOWER LOBE
BRONCHUS- Has 5
main branches.
Apical branch.
Medial basal branch.

20. Bronchopulmonary segment
cont..
Anterior basal branch.
Posterior basal branch.
Lateral basal branch.
LEFT MAIN BRONCHUS- Has two
main branches.
LEFT UPPER LOBE BRONCHUS- Divide
into upper and lower division.
UPPER DIVISION- Has two main branches.
Apico-posterior branch.
 Anterior branch.
LOWER DIVISION- Divide into 2 branches.
Superior lingula.
Inferior lingula.

21. Bronchopulmonary segment
cont..
 LEFT LOWER LOBE
BRONCHUS- Similar to
its counterpart on the
right except that it has
no medial basal. Its
division are:-
Apical branch.
Anterior basal branch.
Posterior basal
branch.
Lateral basal branch.

22. .

23. Bronchopulmonary segment

24. Bronchopulmonary segment
cont..
The regions supplied by individual
bronchi represent definitive and separate
bronchopulmonary segments of the lung
that are combine in a definite scheme
into lobes.
The bronchi divide between 6-20 times
before becoming bronchioles.
Each terminal bronchioles receives
between 2 or 3 respiratory bronchioles
which connect with between 2 and 11
alveolar ducts.
Each duct receive between 2 and 6
alveolar sac.

25. RADIOLOGICAL ANATOMY OF
TRACHEOBRONCHIAL TREE
PLAIN RADIOGRAPH.
TRACHEA- midline translucency with
slight inclination to the right in its lower
half.
Lumen is 1.5-2 cm in diameter.
Right paratracheal stripe is form by
right wall of trachea and pleura, outline
on both sides air.
Left side not seen separately from
mediasternal shadow.

26. Plain frontal chest radiograph

27. ANATOMY OF THE BRONCHI
Bronchi contribute very little to lung
markings seen on plain films.
Proximal bronchi may however be
seen if outline by the lungs.
Posterior segmental bronchi of the left
upper lobe and those of the apical
segments of both lower lobes are
often seen end on.

28. Right is oriented more vertically than
the left.
Bronchus intermedius can be identified
to the right of the cardiac shadow and
medial to the density of the inter lober
artery.
Lower lobe bronchus on the left is not
normally seen as it lies behind the heart
shadow.
Posterior paratracheal stripe is visible if
the lung passes behind the trachea.
Tracheo-oesophageal stripe is visible if
there is air in the oesophagus.

29.  Pulmonary arteries may be seen at the hilum
forming conglomerate density with the pulmonary
veins.
 Right pulmonary artery is seen end on and is oval
in appearance.

30. Lateral chest radiograph

31. Lateral chest radiograph

32. APEARANCE ON CT SCAN
.

33. .

34. .

35. CT SCAN CONT….
BRONCHI
Bronchi may be seen depending upon
their size and orientation.
Narrow slices improves visualization.
Horizontally oriented bronchi may be
seen as tubular structure.
Vertically oriented bronchi may be seen
as air-filled structures.
Posterior wall of left main and upper lobe
bronchi are usually outline by the lung.
Below the hilum lung tissue may also be
seen in contact with the posterior wall of
the lower lobe bronchus

36. .

37. 3 D chest CT reconstruction.

38. Vessels account for most of the lung
markings in CT.
Relationship of the pulmonary arteries
and veins to the bronchi are best seen
at the hila level.
Right pulmonary artery is anterior to the
right bronchus and right superior
pulmonary vein may be seen anterior to
this.
Left pulmonary is seen anterior to the
left main bronchi and above it on a
higher section.

39. .

40. Superior pulmonary vein is separated
from the lower lobe artery at hilar level
by the left bronchus.

41. Bronchography
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42. 6/19/2023 42

43.  Bronchial angiography: blood supply to the
upper trachea is from the inferior thyroid art
and lower part by branches of the bronchial art
 Venous drainage to the inferior thyroid venous
plexus.
 Bronchial arteries appear as opacified tubular
structures or dark tubular structures on
conventional and digital subtraction
angiogram(DSA) respectively which are
branches of the thoracic aorta.
 Bronchial vein drains on the Right to the
azygous system and hemiazygous system on
the left.
6/19/2023 43

44. MRI
Because the lung are of very low proton
density and moves with respiration they
are poorly seen by this method.
Segmental bronchi and fissures are not
seen.
Axial anatomy is the same as seen in
CT.
MR angiography is increasingly being
used to image pulmonary arteries non
invasively.

45. RADIONUCIDE SCAN
Ventilation scan outlines the trachea
and main bronchi in addition to the
lungs.
Gap is seen owing to the mediastinum
and a cardiac notch is seen in the
anterior border of the left lung.
Perfusion scanning may show
differential isotope distribution from
apex to diaphragm, owing to variations
in blood flow associated with this
posture.

46. Normal lung perfusion (A)
ventilation(B)

47. ULTRASOUND SCAN

48. TECHNIQUES
 PLAIN RADIOGRAPH
PA CXR:
 Patient stands erect facing the
bucky/cassette with the feet apart & the
chin resting on the upper border of the
cassette. The back of the hands are
placed on the hips. The shoulders &
forearms are pressed forwards against the
cassette. Ensure the trunk is not rotated.
 Centering point: in the midline at the level
of T6 vertebra
 Direction of central ray: horizontal at 900 to
the film.
6/19/2023 48

49. LATERAL View:
 Patient stands erect with feet apart in
the true lateral position & the affected
side in contact with the cassette. Raise
the arms & fold over the head.
 Centering point: to the midline of the
film through the axilla remote from the
film.
 Direction of central ray: horizontal at
900 to the film.
6/19/2023 49

50. COMPUTED TOMOGRAPHY
 Provides transaxial high resolution images of
the lung parenchyma.
 Indications:
 Identification & characterisation of diffuse lung
dx
 Assessment & delineation of bronchiectasis &
emphysema, assessmt of pleural dx; pleural
effusion
 Characterisation of lung mass:
benign/malignant
 Interventional procedures as a guide to tissue
biopsy & chest drainage
6/19/2023 50

51. Contraindications: pregnancy,
claustrophobic pts
Contrast media: non-ionic CM such as
iohexol, iopamodol
Equipment: CT gantry, pt support table
Patient preparation: explain the procedure
to the pt and obtain an informed consent.
Technique:
 The pt lies supine, head 1st on the scanner
table. Arms are raised & placed behind the
pt’s head, out of the scan plane.
6/19/2023 51

52.  Positioning is aided by transaxial, coronal and
sagittal alignmt lights. The median sagittal
plane is perpendicular and the coronal plane is
parallel to the scanner table top.
 The scan plane is perpendicular to the long
axis of the body to enable transaxial cross-
sectional imaging to be undertaken.
 The scanner table height is adjusted to ensure
that the coronal plane alignment light is at the
level of the mid-axillary line. The pt is now
moved into the scanner until the scan
reference point is at the level of the sternal
notch.
6/19/2023 52

53.  A PA scout film is obtained. Scanogram
is performed commencing 5cm above
and terminating 28cm below the scan
reference point. The PA scan projection
is selected to reduce the radiation dose
to the thymus & breast.
 From this scan image, sections are
prescribed thru the lung fields using 1-
3mm slice width and 10-20mm table
increment.
6/19/2023 53

54.  A high spatial resolution algorithm is
used.
 Scans are routinely taken on
suspended inspiration, but in cases of
air-trapping within the lungs, sections
maybe repeated on suspended
expiration.
 Further scans maybe necessary in the
prone position to redistribute hypostatic
changes occurring at lung bases.
6/19/2023 54

55.  Images may be reconstructed into
coronal, sagittal planes and 3D.
Aftercare: the pt is removed from the
gantry and reassured.
Complications: from radiation.
6/19/2023 55

56. TECHNIQUE OF
BRONCHOGRAPHY
DEFINITION- Is radiographic (x-ray)
examination of the interior
passageways of the respiratory tract.
INDICATION.
Bronchiectasis.
To determine the extend and site of
bronchial obstruction.
Hemoptysis.
Tracheo-oesopageal fistula.
Tumour

57. CONTRAINDICATION
Acute respiratory tract infection.
Poor respiratory reserve.
Extreme hypersensitivity.
Active tuberculosis with pyrexia.
Acute sepsis.
Poor general condition.

58. CONTRAST MEDIA
Ideal contrast agent has not as yet been
developed for bronchography.
Ideally the agent should be:-
Non irritating.
Non sensitizing.
Readily absorbed or expectorated.
Non toxic.
Should not produce granulomatous reaction.
There was considerable diversity of opinion
regard the preferred media for
bronchography.
Advocates of an oily substance slightly
outnumbered those who prefer an aqueous
substance.
Contrast in use now are low osmolar
contrast medium e.g iotrolan, iohexol

59. Advantages of oily contrast media:-
The iodine in dionosil is in organic combination and
therefore the risk of iodine reaction is minimal.
The radiographic evidence of contrast media
disappears within a few hours or days.
Disadvantages of oily contrast media:-
Produce alveolar filling.
Advantages of aqueous contrast media:-
Do not produce alveolar filling.
The contrast is indeed striking and ‘textbook’
bronchogram can frequently be obtain.
Disadvantages of aqueous contrast
media:-
Febrile reaction are much more common.
Greater degree of bronchial obstruction.

60. A solution of barium is employed for
bronchography in patients who are
sensitive to iodine containing
preparation.
About 10-20mls of contrast medium
for unilateral bronchogram and 20-40
mls for bilateral examination.

61. EQUIPMENT.
Fluoroscophy unit.
Over couch tube.
Laryngoscope.
Bronchoscope.
Catheter.
syringe

62. PATIENT PREPARATION.
Chest physiotherapy.
NPO for 6hrs prior to the procedure.
Treat purulent sputum with appropriate
antibiotic.
Premedication with atropine 0.6 mg and
morphine 10 mg.
Steroid prophylaxis and salbutamol for
asthmatic.
Patient may be ask to perform thorough
oral hygiene prior to the procedure.
PRELIMINARY FILMS
Chest (PA & lateral)

63. TECHNIQUE
BRONCHOSCOPHIC METHOD.
Method of choice now in use is direct injection
of contrast medium via bronchoscope.
PER ORAL METHOD.
SIMPLE PASSIVE DEGLUTITION.
PER ORAL SUPRAGLOTTIC INSTILLATION.
PER ORAL TRANSGLOTTIC
CANNULARISATION.
PER ORAL ENDOTRACHEAL
CATETHERISATION.
CRICOTHYROID METHOD.

64. TECHNIQUE CONT….
1)BRONCHOSCOPIC
METHOD
 Nasopharynx is anaesthesizes with local
anaesthetic using 4 or 10% lignocaine spray.
 Patient is sedated with intravenous diazapam.
 Fiber optic bronchoscope is passed via the
nose or mouth into the trachea.
 Bronchial tree is then systematically examined.
 Tip of bronchoscope is inserted into the
appropriate segmental or lober bronchus and
sunction out any secretions before injecting
contrast medium directly into the sunction
channel of the bronchoscope under
fluoroscopy.
 Spot film is then taken under appropriate
turning so as to obtain adequate coating.

65. TECHNIQUE CONT….
2)SIMPLE PASSIVE
DEGLUTITION
Careful regulated local anaesthesia of
the pillars of the faunices and of the
oropharynx is obtain by application of
10% cocaine on cotton wool.
Interruption of the relevant efferent
impulses and normal reflex act of
swallowing cannot occur.
Anaesthesia thought to be complete
when patient cannot elevate his
larynx.
Anaesthesia of upper oesophagus is
avoided.

66. TECHNIQUE CONT….
Within 2 or 3 minutes patient is given 15
to 30mls of iodinised oil to swallow.
Distribution is observed fluoroscopically
and posture modified to suit requirement.
Oil is preceded by 5 mls of 3% procaine.
3) PER ORAL SUPRAGLOTTIC
INSTILLATION.
Use of short canula for dropping the
iodinised oil over the back of the tonque.
Use no local anaesthesia, no laryngeal
mirrow.

67. TECHNIQUE CONT….
Co-operation of patient is necessary and
seldom difficult to obtain.
Anesthesia is helpful in the patient who
persist in gagging.
Tongue should be held out.
Patient is ask as routine not to swallow
and is usually asked to hold onto his
tongue.
Canula should not touch any part of the
mouth or pharynx as deep pressure
sensation may even in the presence of
good surface anaesthesia cause gagging
in certain patient.
Adequate posture is readily attain.

68. TECHNIQUE CONT….
4)PER ORAL TRANSGLOTTIC
CANNULARISATION.
Local anaesthesia of larynx is necessary.
Method require skill in indirect
laryngoscopy.
Adequate posture is difficult for fear of
injuring the larynx with the rigid canula.
Method is prefer on account of supposed
greater certainty of avoiding
oesopahagus.

69. TECHNIQUE CONT….
5) PER ORAL ENDOTRACHEAL
CATETHERISATION.
Soft gum-elastic catheter under indirect
laryngoscopic control passed through the
anaesthesised larynx.
Neck of catheter gripped by the pressure
of the patient teeth.
Has advantage of the ability to get the tip
of the catheter into any particular
bronchus.
Ability to perform selective
bronchoscophy.

70. TECHNIQUE CONT….
6)CRICOTHYROID METHOD
May be perform with patient sitting
against a back rest, supine or lying on
his side.
Neck is kept in extension at all times
in order that the cricoid membrane
may be easily palpated and kept tense
and relatively immobilised.
During insertion of the needle may be
further fixed between the thumb and
fingers of the left hand.

71. TECHNIQUE CONT….
Withdrawal of the pludger of the syringe
will demostrate entery into the larynx by
the appearance in the syringe a large
bubble of air and by characteristic sound
transmitted through the patient mouth.
A very slight head down tilt is possible
provided the head is raised upon a pillow
to prevent the oil from flowing back into
the pharynx.
A full trendelenberg position is never
possible in this method.
Thus failure to fill upper lobe bronchus is
not pathognomonic of the presence of
obstruction of bronchus or of its
absence.

72. .

73. MODIFICATION OF PROCEDURE
To produce bronchogram in children is
generally considered difficult.
Most children under 12 years requires
general anesthesia before the
procedure is possible.

74. TECHNIQUE CONT….
 The following
film studies
are obtained
after injection
of contrast
medium
1. Anteroposterior
recumbent and
lateral views of
the side first
injected
immediately
after injection
and before the
second side is
injected.

75. .
1. Anteroposterior
view of the
chest after both
sides are
injected.
2. An erect
posteroanterior
view after both
sides are
injected.
3. Both oblique
views after both
sides are
injected

76. AP VIEW

77. RIGHT LATERAL VIEW

78. LEFT LATERAL VIEW

79. TECHNIQUE CONT….
AFTER CARE
chest physiotherapy.
NPO till sedative effect resolved.
Patient is instructed to gently cough up
and spit any remaining contrast
medium.
Postural drainage may be
recommended.
Chest x-ray may be perform 24 to 48
hrs after the procedure to asses the
removal of the contrast medium from
the airway
Patient is ask to notify physician for
hoarseness of voice or difficulty in

80. TECHNIQUE CONT….
COMPLICATION
Localized glottic edema.
Local peritracheal infection.
Local peritracheal extravasations of
contrast medium may occur.
Surgical emphysema.
Hemoptysis.
Pain in the neck.
Hoarseness of voice.
Dysphasia.

81. SUMMARY/CONCLUSION
Tracheobronchial tree" or "respiratory
tree" refers to the structures of bronchi
and bronchioles that terminate with the
alveolar ducts, sacs, and, finally, alveoli -
that are contained within the lungs.
These are the structures through which
air passes into the body (usually through
the nose/mouth then the trachea).
Therefore these structures are also
referred to as "airways"

82. . SUMMARY/CONCLUSION
Trachea
Bronchus (Right- or Left- Primary Bronchus)
Lobar Bronchus
Segmental Bronchus
Bronchiole
Terminal Bronchiole
respiratory bronchioles
alveolar duct
alveolus

83. Is there any collaterals for tracheobronchial
tree?

84. .
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