this ppt prepared for year one residency seminar on the anatomy of the trachea bronchus and lung. pls i nedd your comment thanks.

1. Anatomy of trachea, bronchus and
lung
DR. ABRAHAM M.

2. outline
• OBJECTIVE
• INTRODUCTION
• DEFINITION
• GROSS ANATOMY
• ARTERIAL SUPPLY
• VENOUS AND LYMPHATIC DRAINAGE
• NERVE SUPPLY
• REFERENCE

3. OBJECTIVE
• Explain the anatomy and neurovascular supply
to the trachea, bronchus and lung
• Know the anatomy of the trachea and the
central bronchial airways, as well as the
relations between its adjacent structures

4. INTRODUCTION
• from endodermal layer
• laryngotracheal diverticulum the
ventral foregut,
• begins on 4th week and
• complete maturation
approximately 8 years of age.
• Fetal breathing movements
observed at 20–21 weeks.
• surfactant

6. TRACHEA
DEFINITION
• The trachea or a wind pipe is membranocartilaginous
tube which extends downwards as a continuation of
the larynx.
• It begins at the lower border of cricoid cartilage
opposite C6 , passes downward through the neck and
the superior mediastinem of the thorax, and ends by
dividing into right and left bronchi, opposite the sternal
angle.

7. • The bifurcation of trachea corresponds with
lower border of T4 In cadaver and in supine
position, but it extends to T6 in the living and
in standing position

9. • In an adult person, the length is
between 10 and 13 cm,
• 18–22 cartilage rings
• the coronal diameter 2–2.5 cm,
• the sagittal diameter 1.4 to 1.8 cm
• Internal measurement 12mm in
adult.
• In newborn, 3mm which persists
upto 3yrs off life .
• There after the lumen increases by
1mm each year upto 12th year after
which it remains fairly constant.

12. Intralumenally

13. • The total volume of tracheobronchial secretions
varies normally from 10 mL/d to 100 mL/d, under
the infuence of local irritants.
• Irritative substances to the mucosa, e.g. tobacco
smoke, may produce squamous metaplasia and
damage to the cilia.

14. Relation of the trachea
In the neck
A. anteriorly
1. Jugula venous arch crossing in the supra sternal space
2. sternohyoid and sternothyroid muscles
3. Isthmus of thyroid gland
4. Below the isthmus covered by pretracheal fascia inferior
thyroid vein, occasionally arteria thyrioidia ima

15. B. Posteriorly
1. Oesophagus
2. Recurrent laryngeal nerve
C. On each side
1. Lateral lobe of the thyroid gland
2. Common carotid and inferior thyroid arteries

16. IN THE THORAX
• Thoracic - in the superior mediastinum, 5-6 cm
– Anteriorly - brachiocephalic artery & left common carotid artery
– Posteriorly – esophagus and recurrent laryngeal nerves
– Left – arch of aorta, left common carotid and left subclavian arteries, left
recurrent and pleura
– Right - vagus, azgos vein and pleura

17. Arterial supply
• inferior thyroid artery
• which pass either anteriorly or posteriorly to
the recurrent laryngeal nerves
• bronchial arteries which arise from the
descending aorta

20. Venous and lymphatic drainage
• Mostly drain into inferior thyroid vein .
• Drain into pre-tracheal and para-tracheal
lympnodes

21. Nerve supply
• Parasympathetic nerves are derived from both
vagus and recurrent laryngeal nerves; are
– motor to trachealis ms ,
– secretomotor to glands and
– sensory to mucous membrane.
• Sympathetic (T1-T4) – smooth muscles (dilator)
and blood vessels (vasoconstrictors

22. BRONCHI AND LUNG
• the two principal bronchi
begin at the bifurcation of
trachea and enter the hilum
of the corresponding lung
• each bronchus connsists of
extra pulmonary and intra
pulmonary parts.

23. RIGHT BRONCHUS
• right bronchus is wider , shorter and more
vertical than the left bronchus
• length of extra pulmonary part is about 2cm
• it passes below the azygos vein, enters the
root of the right lung `and reaches the hilum
at the level of 5th thoracic vertebra

25. • With in the lung , the principal bronchus divides
into secondary or lobar bronchi , one for each
lobe.
• Each secondary bronchus subdivides into
segmental or tertiary bronchi

27. • The area of the lung aerated by a teritary
bronchus is known as bronchopulmonary
segment, which is an independent respiratory
district.
• A bronchopulmonary segment is the smallest
functionally independent region of a lung

29. • Beyond the tertiary/segmental bronchi , there
are 20 to 25 generations of branching
conducting bronchioles that eventually end as
terminal bronchioles

30. • Each terminal bronchiole gives rise to
several generations of respiratory bronchioles,
characterized by scattered, thin-walled
outpocketings (alveoli) that extend from
their lumens.

31. • The pulmonary alveolus is the basic structural
unit of gas exchange in the lung. Due to the
presence of the alveoli, the respiratory
bronchioles are involved both in air
transportation and gas exchange.

32. • Each respiratory bronchiole gives rise to 2–11
alveolar ducts, each of which gives rise to 5–6
alveolar sacs. Alveolar ducts are elongated airways
densely lined with alveoli, leading to common spaces,
the alveolar sacs, into which clusters of alveoli open.
• New alveoli continue to develop until about age 8
years, by which time there are approximately 300
million alveoli.

33. Distribution of the right principal
bronchus
• Upper lobe bronchus (eparterial) aspect
• about 2cm distal to the bifurcation of trachea
• divides usually into three tertiary bronchi
apical , posterior and anterior

35. • About 2cm below the origin of the upper lobe
bronchus , gives off from the front a lobar
bronchus to the middle lobe of the lung,
• where it divides into lateral and medial
tertiary bronchi.

36. • The middle lobe bronchus is long and
surrounded by a group of hilar lymph nodes
which drain lymphatics from middle and lower
lobes of right lung.

37. • Remaining part of supplies the lower lobe of
the right lung by five tertiary branches
1. Apical
2. Anterior basal
3. Middle basal
4. Posterior basal
5. Lateral basal

38. LEFT BRONCHUS
• left principal bronchus is longer, narrower, and
more horizontal than the right bronchus.
• length of extra pulmonary part is about 5cm.
• it enters the lung root and reaches the hilum
at the level of 6th thoracic vertebra.

39. INTRA PULMONARY PART
• The left principal bronchus divides into upper
and lower lobar bronchi to supply the
respective lobe of the left lung.
• upper lobar bronchus arises about 5cm distal
to bifurcation of trachea
• divides into ascending and descending
branches.

40. • ascending branches subdivides into three
tertiary bronchi, apical, posterior and anterior
• descending branch subdivides into upper and
lower lingular bronchi to supply the lingula

41. • lower lobe bronchus passes downwards, and
divides usually into four teritary bronchi
– apical,
– anterior basal,
– lateral basal and
– posterior basal.

42. Right bronchus Left bronchus
wider narrower
shorter longer
steeper More horizontal
2cm 5cm

43. Lung
• The two lungs are organs of respiration and lie
on either side of the mediastinum surrounded
by the right and left pleural cavities. Air enters
and leaves the lungs via main bronchi, which
are branches of the trachea.

44. Characteristic features
• Lung is porous, highly elastic and spongy in
texture
• It crepitates to touch and floats on water
• In still born lungs sink in water
• In newborn it is rosy pink
• In adult it is dark grey

45. • An apex, the blunt superior end of the lung
ascending above the level of the 1st rib into the
root of the neck that is covered by cervical
pleura.
• A base, the concave inferior surface of the lung,
opposite the apex, resting on and
accommodating the ipsilateral dome of the
diaphragm.

46. Lobes and fissures
• The right lung has three lobes (upper, middle
and lower) and
• two fissures (oblique and horizontal).
• In more than 50% of cases, the horizontal
fissure is incomplete and the middle lobe is
fused to the anterior part of the upper lobe.

47. • The left lung has two lobes (upper and lower)
separated by the oblique fissure
• The orientations of the oblique and horizontal
fissures determine where clinicians should
listen for lung sounds from each lobe

48. Anterior view

49. Posterior view

50. • When planning resection, surgeons look
carefully for the fissures on CT scans;
• they are usually visible and will indicate which
lobe contains a lesion and whether more than
one lobe is involved.

51. • Each lung has a half-cone shape, with a base,
apex, two surfaces, and three borders

52. • The two surfaces—the costal surface lies
immediately adjacent to the ribs and
intercostal spaces of the thoracic wall.
• The mediastinal surface lies against the
mediastinum anteriorly and the vertebral
column posteriorly

53. • The three borders—the inferior border of the
lung is sharp and separates the base from the
costal surface.
• The anterior and posterior borders separate the
costal surface from the medial surface.

54. Root and hilum
• The root of each lung is a short tubular collection
of structures that together attach the lung to
structures in the mediastinum. It is covered by a
sleeve of mediastinal pleura that reflects onto the
surface of the lung as visceral pleura.
• The region outlined by this pleural reflection on
the medial surface of the lung is the hilum, where
structures enter and leave.

55. • A thin blade-like fold of pleura projects
inferiorly from the root of the lung and
extends from the hilum to the mediastinum.
This structure is the pulmonary ligament.

58. Arterial supply
• Bronchial arteries
– right bronchial artery
• third posterior intercostal artery
• occasionally, it originates from the upper left bronchial artery
• Two left bronchial arteries
– anterior surface of the thoracic aorta
• Superior and inferior left bronchial artery
• The most distal branches of the bronchial arteries
anastomose with branches of the pulmonary arteries in
the walls of the bronchioles and in the visceral pleura.

60. Venous drainage
• bronchial veins
– Superficial
• into the azygos vein on the right
• into the superior intercostal vein
or hemiazygos vein on the left.
– Deep
• Receive blood from
intrapulmonary bronchi and
bronchioles
• Terminate into one of the
pulmonary veins or directly into
the left atrium

61. Lymphatic drainage
– Superficial set
• Ramifies beneath the pulmonary pleura and around the
extra pulmonary bronchi, drains in to broncho pulmoonary
lymph nodes at the hilum
– Deep set is arranged around the intrapulmonary
bronchi and bronchiole,
• These lymphatics converge centripetally towards the hilum
and drain into bronchopulmunary lymph nodrs
• The lymph vessels in the interlobular septa communicate
with pleural lymphatics

63. Innervation
• anterior pulmonary plexus and posterior
pulmonary plexu
• These interconnected plexuses lie anteriorly
and posteriorly to the tracheal bifurcation and
main bronchi.
• The anterior plexus is much smaller than the
posterior plexus.

64. • Parasympathetic preganglionic fibers
– Motor to airway smooth muscle (constriction), glands
(secretomotor), inhibitory to vascular smooth muscle
(vasodilation)
• Sympathetic fibers
– These are inhibitory to the smooth muscle and mucus
glands of bronchial tree.

66. reference