LUNG RESPIRATORY SYSTEM THORACIC CAVITY.ppt

LUNGS

1. LUNGS
MS.R.SIVA ANANDHI
ASSISTANT PROFESSOR ,
VISTAS
CHENNAI

2. LUNGS
-
-
-
-
-
-
The lungs are a pair of respiratory organs situated in the THORACIC CAVITY.
Each lung invaginates the corresponding pleural cavity.
The RIGHT and LEFT lungs are separated by the MEDIASTINUM.
Lungs are SPONGY in texture. In the young, the lungs are brown or grey in colour.
The right lung weighs about 700g. It is about 50 to 100g heavier than the left lung.
There are 10 bronchopulmonary segments in each lung.
FEATURES
- Each lung is CONICAL in shape. It has
o An APEX at the upper end
o BASE resting on the diaphragm
o THREE BORDERS- ANTERIOR, POSTERIOR, and INFERIOR
o TWO SURFACES- COSTAL and MEDIAL.
▪Medial surface is divided into VERTEBRAL and MEDIASTINAL parts.
- THE APEX
o Blunt and lies above the level of the ANTERIOR END of FIRST RIB
o It reaches nearly 2 . 5 cm above the MEDIAL ONE- THIRD of the clavicle, just medial
to the SUPRACLAVICULAR FOSSA.

5. THE BASE
o It is SEMILUNAR and CONCAVE
o Rests on the DIAPHRAGM which separates the RIGHT LUNG from the RIGHT LOBE of
the liver and LEFT LUNG from the LEFT LOBE OF LIVER, fundus of STOMACH and
SPLEEN
ANTERIOR BORDER
o It is very thin and shorter than the posterior border.
o On the RIGHT SIDE, it is vertical
o Anterior border of the LEFT LUNG shows a wide CARDIAC NOTCH below the level
of the FOURTH COSTAL CARTILAGE.
o HEART and pericardium are not covered by the lung in the region of this notch.
POSTERIOR BORDER
o Thick and ill defined
o Corresponds to medial margins of head of RIBS
o Extends from level of 7th CERVICAL SPINE to 10thTHORACICSPINE
- INFERIOR BORDER
o Separates base from the costal and medial surfaces.

6. - COSTAL SURFACE
o LARGE and CONVEX
o It is in contact with COSTAL PLEURA and overlying
THORACIC WALL.
- MEDIAL SURFACE
o Divided into POSTERIOR OR VERTEBRAL PART and an ANTERIOR OR
MEDIASTINAL PART
o VERTEBRAL PART is related to vertebral bodies, IVD, posterior intercostal vessels and
splanchnic nerves
o MEDIASTINAL PART is related to mediastinal septum, and shows a CARDIAC
IMPRESSION,
HILUM and a number of other impressions which DIFFER on the TWO SIDES.

10. •FISSURES AND LOBES OF THE LUNG
•RIGHT LUNG is divided into 3 LOBES (UPPER, MIDDLE and LOWER) by two
fissures (OBLIQUE and HORIZONTAL)
•LEFT LUNG is divided into 2 LOBES by the OBLIQUE FISSURE.
•OBLIQUE FISSURE cuts into the whole thickness of the lung, except at the HILUM.
o It passes OBLIQUELY DOWNWARDS and FORWARDS, crossing the posterior
border about 6cm below the apex and the inferior border about 5cm from the median
plane
•In the RIGHT LUNG, the HORIZONTAL FISSURE passes from the anterior border
upto the OBLIQUE
•FISSURE and separates a wedge- shaped MIDDLE LOBE from the UPPER LOBE.
o It runs horizontally at the level of the FOURTH COSTAL CARTILAGE and meets the
OBLIQUE FISSURE in the MIDAXILLARY LINE.
- LINGULA- tongue shaped projection of left lung below the CARDIAC NOTCH.

11. ROOT OF THE LUNG
- It is a SHORT, BROAD PEDICLE which connects the MEDIAL SURFACE of the lung to the
MEDIASTINUM.
- It is formed by structures which either ENTER or COME OUT of the lung at the hilum.
- The roots of the lungs lie opposite the bodies of 5th, 6th and 7th thoracic vertebrae.
CONTENTS
Root is made up of the following structures
o Principal bronchus on LEFT SIDE
o One PULMONARY ARTERY
o Two PULMONARY VEINS
o BRONCHIAL ARTERIES, one on right and two on left side
o BRONCHIAL VEINS
o Anterior and Posterior PULMONARY PLEXUS of nerves
o LYMPHATICS of the lung
o BRONCHOPULMONARY LYMPH NODES
o AREOLAR TISSUE

14. • ARRANGEMENT OF STRUCTURES IN THE ROOT
• From anterior to posterior, it is similar on the two sides
• a) Superior pulmonary vein
• b) Pulmonary artery
• c) Bronchus
• From above downwards, it is different on the two sides
•- Right Side
• a. Eparterial bronchus
• b. Pulmonary artery
• c. Inferior pulmonary vein
•- Left side
• a. Pulmnary artery
• b. Bronchus
• c. Inferior pulmonary vein

16. RELATIONS OF THE ROOT
- ANTERIOR
1. Common on the two sides
a. Phrenic nerve
b. Pericardiophrenic vessels
c. Anterior pulmonary plexus
2. On the right side
a. Superior vena cava
b. Part of right atrium
- POSTERIOR
1. Common on the two sides
a. Vagus nerve
b. Posterior pulmonary plexus
2. On the left side
a. Descending thoracic aorta
- SUPERIOR
1. On the right side- terminal part of AZYGOS VEIN
2. On the left side- ARCH OF AORTA
- INFERIOR- Pulmonary ligament

17. ARTERIAL SUPPLY
- BRONCHIAL ARTERIES supply nutrition to the bronchial tree and to the pulmonary
tissue.
o On the RIGHT SIDE, there is one bronchial artery which arises from the third RIGHT
POSTERIOR INTERCOSTAL ARTERY
o On the LEFT SIDE, there are two bronchial arteries both of which arise from the
DESCENDING THORACIC AORTA
- Deoxygenated blood is brought to the lungs by the TWO PULMONARY ARTERIES and
oxygenated blood is returned to the heart by FOUR PULMONARY VEINS.

20. • VENOUS DRAINAGE OF THE LUNGS
• Venous blood from the first and second divisions of the bronchi is carried by
BRONCHIAL VEINS.
o RIGHT BRONCHIAL VEINS drain into AZYGOS VEIN
o LEFT BRONCHIAL VEIN drain into HEMIAZYGOS VEIN.
Greater part of venous blood from the lungs is drained by the PULMONARY VEINS
LYMPHATIC DRAINAGE
- SUPERFICIAL VESSELS drain the PERIPHERAL LUNG TISSUE
DEEP LYMPHATICS drain the BRONCHIAL TREE, PULMONARY VEINS and
CONNECTIVE TISSUE SEPTA
NERVE SUPPLY
- PARASYMPATHETIC NERVES are derived from the vagus.
- SYMPATHERIC NERVES are derived from the SECOND TO FIFTH
SYMPATHETIC GANGLIA

23. -
-
-
-
-
-
-
BRONCHIAL TREE
The TRACHEA divides at the level of the lower border of 4th THORACIC VERTEBRA into
two
PRIMARY PRINCIPAL BRONCHI, one for each lung.
The RIGHT PRINCIPAL BRONCHUS is 2 . 5 cm long. It is shorter, wider and more in line
with the
trachea than the left principal bronchus.
The LEFT PRINCIPAL BRONCHUS is 5cm. It is longer, narrower and more oblique than
the right
bronchus.
Right bronchus makes an angle of 25 degrees with the tracheal bifurcation.
Left bronchus makes an angle of 45 degrees with the trachea.
Each principal bronchus enters the lung through the HILUM, and divides into

24. •SECONDARY LOBAR BRONCHII, one for each lobe of the lungs.
o RIGHT SIDE- 3 LOBAR BRONCHI
o LEFT SIDE- 2 LOBAR BRONCHI
•Each lobar bronchus divides into TERTIARY OR SEGMENTAL BRONCHI, one for each
•BRONCHOPULMONARY SEGMENT.
o Right side- 10
o Left side- 10
•Segmental bronchi divide repeatedly to form very small branches called TERMINAL
BRONCHIOLES.
•Still smaller branches are called RESPIRATORY BRONCHIOLES.
•Each respiratory bronchiole aerates a small part of the lung known as PULMONARY UNIT

25. - The respiratory bronchiole ends in microscopic passages which are termed
1) Alveolar ducts
2) Atria
3) Air saccules
4) Pulmonary alveoli
BRONCHOPULMONARY SEGMENTS
- These are well defined anatomic, functional and surgical sectors of lung.
- Each one is aerated by a tertiary or segmental bronchus.
- Each segment is pyramidal in shape with its apex directed towards the root of the lung

29. RIGHT LUNG LOBE SEGMENTS
UPPER APICAL
POSTERIOR
ANTERIOR
MIDDLE
LATERAL
MEDIAL
LOWER SUPERIOR
MEDIAL BASAL
ANTERIOR BASAL
LATERAL BASAL
POSTERIOR BASAL

30. LEFT LUNG LOBES SEGMENTS
UPPER
UPPER DIVISION
LOWER DIVISION
APICAL
POSTERIOR
ANTERIOR
SUPERIOR LINGULAR
INFERIOR LINGULAR
LOWER SUPERIOR
MEDIAL BASAL
ANTERIOR BASAL
LATERAL BASAL
POSTERIOR BASAL