Thorax

1. Lungs
(Pulmones)
Dr M Idris Siddiqui

2. The Lungs
• A pair of sponge like elastic organ which fills
greater part of chest cavity.
• Lungs are the organs of respiration and are
enclosed by the right and left pleural
cavities, located on both side of
the Mediastinum.
• The lung is more massive and voluminous
behind than in front.
• Each lung has a conical/pyramidal shape.

5. Right lung Left lung
Slightly larger & wider Slightly smaller, narrower
Weighs approximately 700 g Weighs around 650 g
Has three lobes. Has two lobes
Two fissures:
Oblique fissure
Horizontal fissure
One fissure:
Oblique fissure
only
No cardiac notch Has cardiac notch
Hilum has two bronchi:
Eparteial
Hyparterial
Hilum has one bronchus
only

7. Lobes
• The right and left lungs do not have an identical
lobular structure.
• The right lung has three lobes; superior, middle and
inferior. The lobes are divided from each other by
two fissures:
– Oblique fissure – Runs from the inferior border of the
lung in a superoposterior direction, until it meets the
posterior lung border.
– Horizontal fissure– Runs horizontally from the sternum,
at the level of the 4th rib, to meet the oblique fissure.
• The left lung has two lobes; superior and inferior
lobes, which are separated by only oblique fissure

9. The lungs
• The lungs have an apex, base, three surfaces and three
borders.
• Each lung consists of:
• Apex – The blunt superior end of the lung. It projects
upwards, above the level of the 1st rib and into the
floor of the neck.
• Base – The inferior surface of the lung, which sits on
the diaphragm also forms diaphragmatic surface.
• Lobes (two or three) – These are separated by fissures
within the lung.
• Surfaces (three)
• Borders (three)

10. Anterior relations of apex of the lungs
1. Subclavian artery
2.Internal thoracic artery
3. Scalenus anterior

12. Posterior relations of apex of the lung
• Neck of the 1st rib.
• Structures between apex & neck of 1st rib.
• From medial to lateral
1. Sympathetic chain(cervicothoracic ganglion)
2. Supreme intercostal vein
3. Superior intercostal artery
4. Ventral ramus of 1st thoracic nerve

13. THE BORDERS
• The Three Borders
– The Inferior border(or circumferential border) of the
lung is pointed and also splits the base(diaphragmatic
surface) from the costal surface.
– The Anterior border is sharp & divides the costal surface
mediastinal surface. The part of lung adjacent to
anterior border is thin & wedge shaped.
• On the left lung, the anterior border is marked by a
deep notch, created by the apex of the heart. It is
known as the cardiac notch.
– The Posterior or vertebral border is smooth and
rounded. It occupies paravertebral gutter.

14. Surfaces
• These correspond to the area of the thorax that they
face.
1. The costal surface (lateral) is smooth and convex. It
faces the internal surface of the chest wall. It is related
to the costal pleura, which separates it from the ribs
and innermost intercostal muscles.
2. The mediastinal (medial) surface of the lung faces the
lateral aspect of the middle mediastinum. It faces the
hilum of the lung and the vertebral column.
3. The base of the lung is formed by the diaphragmatic
(inferior)surface. It rests on the dome of the
diaphragm, and has a concave shape. This concavity is
deeper in the right lung, due to the higher position of
the right dome overlying the liver.

15. COSTAL SURFACE
• It is large, smooth, and convex. It is covered by
the costal pleura and endothoracic fascia.
• Relations:
• It is related to the lateral thoracic wall.
• The number of ribs related to this surface is as
follows:.
– Upper 6 ribs in midclavicular line
– Upper 8 ribs in midaxillary line
– Upper 10 ribs in scapular line

17. The mediastinal surface of right lung
A. The most important feature is the hium of the lung & line of attachment of pulmonary
ligament.
B. In front of the hilum & pulmonary ligament:
1. Wide concave impression-for right atrium
2. Two vertical grooves
I. The groove for superior vene cava in front of the root of the lung
II. The groove for infrerior vene cava in front of lower part of the pulmonary
ligament
C. Behind the hilum & pulmonary ligament
i. The groove for esophagus lies between hilum and pulmonary ligament(in front).
ii. The groove for the azygos vein (behind)
D. Immediately above the hilum
– There is a curved groove for the arch of the azygos vein.
E. Above the level of the arch of the azygos vein 3 grooves:
1. The groove for superior vena cava in front of the hilum
2. The groove for the trachea lies behind the groove for superior vena cava
3. The groove for the esophagus lies behind the groove for the trachea

18. Right
lung

20. The mediastinal surface of right lung
A. The most important feature is the hium of the lung & line of
attachment of pulmonary ligament.
B. In front of the hilum & pulmonary ligament:
Wide & deep concave area (cardiac impression) for left ventricle
C. Behind the hilum & pulmonary ligament
– Broad longitudinal groove for the descending aorta
D. Immediately above the hilum
– Broad groove for the arch of aorta
E. Above the level of the arch of the aorta.
– Two grooves:
1. for the left subclavian artery
2. for the left common carotid artery lie in front of
the groove for the left subclavian artery
(two grooves conceal the trachea)

21. Left
lung

23. Comparision of mediastinal sufaces of both lungs
Mediastinal surface of the right lung Mediastinal surface of the left lung
Right atrium Left ventricle
Superior and inferior vena cavae Ascending aorta
Azygos vein
Arch of aorta and descending thoracic
aorta
Right brachiocephalic vein
Left subclavian and left common carotid
arteries
Esophagus and trachea Esophagus and thoracic duct
Three neural structures:
(a) right phrenic nerve,
(b) right vagus nerve, and
(c) right sympathetic chain.
Four neural structures:
(a) left phrenic nerve,
(b) left vagus nerve,
(c) left sympathetic chain.
(d) Left recurrent pharyngeal nerve

25. Smaller structure which leave no
mark on mediastinal surface
1. Phrenic nerve
2. Right vagus on trachea &
Left vagus on arch of aorta.
3. Left superior interostal vein on aortic
arch.
4. Thoracic duct on left side of esophagus

26. Relations of base of the lung
(inferior or diaphragmatic surface)
• On the right side:
• The right lung is separated by the right dome of the
diaphragm from:
– The liver .
• On the right side:
• The left lung is separated by the left dome of the
diaphragm from:
– The spleen
– The fundus of stomach

27. ROOT AND HILUM

28. The Root of The Lung
• The lung root is the region where it is connected to
the mediastinum.
• Each root contains:
– Pulmonary artery (A)
– A bronchus (B) main structures
– Two pulmonary veins,(V)
– Bronchial vessels,
– Pulmonary plexus of nerves
– Lymphatic vessels.
• The mediastinal pleura and the visceral pleura
encircle the root of the lung.
– The vagus nerves travel directly posterior to the roots of the
lungs in the mediastinum, while anterior to them the
phrenic nerves travel directly.

29. Vessels in the root of the lung
• There are 3 sets of vessels in the root of the
lung.
• One pulmonary artery:
–Carries venous blood, superiormost on left.
• Eparterial bronchus may be superiormost on right .
• Two pulmonary veins(superior & inferior):
–Carries arterial blood, anteriormost &
inferiormost respectively.
• Small bronchial arteries:
–Carries blood to the wall of the bronchial tree.

30. The Hilum of the LUNG
• The Hilum is a large depressed region, where
structures enter and leave the lung and is
bordered by this pleural duplication over the
medial surface of the lung.
• Inferiorly, a fold of pleura, sleeve like hangs
from the hilum to the mediastinum and
protrudes via the root of the lung forming the
pulmonary ligament.

31. Pulmonary ligament
• Pulmonary ligament is the term used for the
fold (Sleeve of pleurae) due to double reflection
as it goes down.
• As the wrist is surrounded by the cuff of the coat, in the same
manner the root of the lung is surrounded by the pleura.
• From the root of the lung, pulmonary ligament
stretches itself towards the diaphragm and
the mediastinum.
• Few lymphatics and loose areolar tissue are
contained wholly in the fold.

32. Pulmonary ligament
• Functionality
• It gives a dead space into which the pulmonary
veins can expand during increased venous return as
during exercise.
• It enables the descent of the root of the lung with
all the descent of diaphragm during motivation.
• Consequently, the apex of lung comes down from
the rough suprapleural membrane making an
empty space below the membrane. Now the apex
of lung can enlarge into this empty space.

33. RIGHT LUNG
• The right lung consists of three Lobes along with
two Fissures.
• Generally, since by hollow of visceral pleura they
are divided nearly till the hilum, the lobes are freely
movable alongside each other. These invaginations
create the fissures:
• The Oblique Fissure splits the inferior lobe via the
superior lobe and the middle lobe of the right lung.
• The Horizontal Fissure divides the superior lobe
from the middle lobe.

34. LEFT LUNG
• The left lung has two lobes divided by an Oblique
Fissure and it is smaller than the right lung.
• Compared to the resembling fissure of the right
lung, the oblique fissure of the left lung is a little
more oblique in shape.
• Throughout soundless respiration, a curved line on
the thoracic wall that begins among the spinous
protuberance of vertebrae t3 and T4, intersects the
fifth interspace laterally and trails the outline of rib
VI anteriorly, marks the estimated position of the
left oblique fissure

35. Relations of medial surfaces of both lungs
Left Lung Right Lung
Heart
Arch of aorta
Thoracic aorta
Oesophagus
Oesophagus
Heart
Inferior vena cava
Superior vena cava
Azygous vein

36. How to know a right from a left lung
Put the lung so that
• The apex lies above and the base below.
• The hilum lies medially
• The anterior sharp border lies in front
while its posterior full and rounded
border lies behind.

37. BRONCHOPULMONARY SEGMENTS
• The Bronchopulmonary segments are well defined,
wedge-shaped sectors of the lung, that are aerated
by tertiary (segmental) bronchi.
• Well defined anatomical, independent resectable
structural & functional unit supplied by segmental
bronchus,artery & vein.
• It is a subsection of the lobe of the lung.
• It is pyramidal in shape with apex pointed in the
direction of the hilum and base in the direction of
the top layer of the lung.
• It is separated by the connective tissue.

38. BRONCHOPULMONARY SEGMENTS
• It is aerated by the segmental (tertiary) bronchus.
• Every segment has its very own artery, a segmental
branch of the pulmonary artery.
• The segmental veins (the tributaries of pulmonary
veins) run in the intersegmental planes of the
connective tissue.
– Intersegmental septum
• Every segment has its own lymphatic drainage and
autonomic provide.

40. Segmental Resection Of The Lung
• It is possible to dissect out and remove the
diseased section leaving the surrounding tissue
undamaged. This process is named segmental
resection.
• During segmental dissection, it is significant not to
ligate intersegmental veins as they are going to
interfere with all the venous drainage of the
surrounding healthy sections.
– Segmental resection is most commonly performed in
bronchiectasis.

41. Bronchial
Tree

42. ARTERIAL
SUPPLY

43. Blood supply of the lungs
• Due to a bronchial and a pulmonary circulation, the
lungs have a double blood supply.
• BRONCHIAL CIRCULATION
• The bronchial arteries that leave the aorta supplies
oxygenated blood to the airways of the lungs to the
bronchial circulation.
– There are usually three arteries which divide together with
the bronchi and bronchioles, two to the left lung and one to
the right.
• PULMONARY CIRCULATION
• The pulmonary circulation transports deoxygenated
blood via the heart to the lungs and returns the
oxygenated blood to the heart to supply the rest of the
body.

44. The bronchial arteries
• The bronchial arteries supply blood for nutrition of the
lungs, the supporting tissues of the lungs, and the
visceral pleura.
• The two left bronchial arteries usually arise directly
from the thoracic aorta.
• The single right bronchial artery may arise
– Directly from the aorta.
– Most commonly it arises indirectly, from the right 3rd
posterior intercostal artery)
– Or from a common trunk with the left superior bronchial
artery.
• The distalmost branches of the bronchial arteries
anastomose with branches of the pulmonary arteries in
the walls of the bronchioles and in the visceral pleura.

45. Bronchial veins
• Blood leaves the lungs via four pulmonary
veins (two for each lung).
• The bronchial veins provide venous drainage.
• The right bronchial vein drains into the azygos
vein, whilst the left drains into the accessory
hemiazygos vein.

46. Nerve Supply
• The nerves of the lungs are derived from
the pulmonary plexuses. They feature sympathetic,
parasympathetic and visceral afferent fibres:
• Parasympathetic: Derived from the vagus nerve. They
stimulate secretion from the bronchial glands,
contraction of the bronchial smooth muscle, and
vasodilation of the pulmonary vessels.
• Sympathetic: Derived from the sympathetic trunks.
They stimulate relaxation of the bronchial smooth
muscle, and vasoconstriction of the pulmonary vessels.
• Visceral afferent: Conduct pain impulses to the sensory
ganglion of the vagus nerve.

47. Nerve
supply
of lung

48. LYMPHATIC DRAINAGE
• Superficial, or subpleural, along with the deep
lymphatics of the lung surrounding the roots
of lobar and main bronchi and alongside the sides
of the trachea drain into lymph nodes known as
Tracheobronchial Nodes.
• No lymph vessels are located in walls of pulmonary
alveoli.
• Superficial plexus lies deep to visceral pleura
• Deep plexus is located in submucosa of bronchi & in
peribroncheal connective tissue(intrapulmonary)

50. BRONCHITIS
• Bronchitis is swelling of the bronchi. A swelling of
the mucous membrane is caused by the inflamed
tissue. This increases mucous production with a
decrease in the ability to move the mucus up to
the throat by the Cilia. This results in impairing
breathing by a decrease in the width of
the Bronchial Tubes.
• An infection with bacteria or viruses can cause
Bronchitis. Irritants like air pollutants or cigarette
smoke can also develop it by increased exposure

51. EMPHYSEMA
• The destruction of the walls of the alveoli causes
Emphysema. It is incurable and it is a progressive
degenerative disease.
• Prolonged exposure to respiratory irritants like
tobacco smoke and air pollutants is main cause of
emphysema.
• The surface area of the respiratory membrane is
decreases.
• The alveolar walls also lose the ability of the lungs
to recoil and expel air decrease in elasticity.
Enlargement of the thoracic cavity and shortness of
breath are common symptoms.

52. Pulmonary Embolism
• Pulmonary Embolism
• A pulmonary embolism refers to the obstruction
of a pulmonary artery by a substance that has
travelled from elsewhere in the body.
• The most common emboli are:
– Thrombus – responsible for the majority of cases and
usually arises in a distant vein.
– Fat – following a bone fracture or orthopaedic surgery.
– Air – following cannulation in the neck.

53. Pancoast Syndrome
• It takes place because of engagement of structures associated with
the posterior aspect of the apex of lung by the cancer of the lung
apex.
• Clinical Features
1. Pain along the medial side of forearm and hand, and wasting of small
muscles of the hand because of engagement of ventral ramus of T1.
2. Horner’s syndrome, because of engagement of sympathetic chain.
3. Erosion of first rib.
4. Cancer of lung apex may spread to include abutting structures, like
subclavian or brachiocephalic vein, subclavian artery, phrenic
nerve causing subsequent signs and symptoms.
5. Venous engorgement and edema in neck, face, and arm due
participation of subclavian and brachiocephalic veins.
6. Reduced brachial and/or radial pulse because of compaction on
subclavian artery.
7. Paralysis of hemidiaphragm because of infiltration of phrenic nerve.

54. Azygos lobe
• An azygos lobe is an accessory
lobeb created when a laterally
displaced azygos vein creates a
deep pleural fissure into the
apical segment of the right
upper lobe during
embryological development.
• It is a normal anatomic variant
of the right upper lobe due to
invagination of the azygos vein
and pleura during
development in the fetus.