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1. ANATOMY OF
RESPIRATORY SYSTEM
BY :
MMANTTHAN PUROHIT

2. RESPIRATORY SYSTEM
• SURFACE LANDMARKS OFTHORAX ( BONY & SOFTTISSUE )
• BONES, JOINTS, & MUSCLES
• LUNGS & PLEURA ( SURFACE MARKING )
• TRACHEA & BRONCHIALTREE
• VASCULAR SUPPLY, NERVE SUPPLY, LYMPHATIC DRAINAGE

3. SURFACE LANDMARKS
• BONY LANDMARKS :
1. SUPRASTERNAL OR JUGULAR NOTCH : superior border of manubrium
between sternal ends of clavicle.
2. STERNAL ANGLE OR ANGLE OF LOUIS : it is felt as a transverse ridge
about 5 cm below the suprasternal notch.
• This is an important landmark for the following reasons :

4. A.The 2nd costal cartilage and 2nd rib lie at this place.The ribs are
contoured downwards from this level.
B.It marks the plane which separates superior and inferior mediastinum
C. Ascending aorta ends at this level.
D.The arch of aorta begins and also ends at this level.
E. The descending aorta begins at this level.

5. F. The trachea divides in to 2 principal bronchi
G.The azygos vein arches over the root of the right lung and enters into
SVC.
H.The pulmonary trunk divides into 2 pulmonary arteries just below this
level.
I. The thoracic duct crosses from right to left side at the level ofT5 and
reaches the upper left side of sternal angle.
J. It marks the upper limit of the base of the heart and cardiac plexus is
situated at the same level

6. 3. XIPHISTERNAL JOINT : the costal margin on each side is formed by 7th to
10th costal cartilages, there lies the infrasternal or subcostal angle.The
depression is felt and is known as epigastric fossa.
4. COSTAL CARTILAGES : the 2nd costal cartilage is attached to the sternal
angle.The 7th costal cartilage bounds the upper part of infrasternal angle.
The 10th costal cartilage forms the lower part of costal margin.

7. 5. RIBS : the scapula overlies the 2nd to 7th ribs on the posterolateral aspect
of the chest wall.The 10th rib is the lowest point lies at the level of L3
6.THORACICVERTEBRAL SPINES : the 1st prominent spine is felt at the
lower part of the back of the neck is that of the C7, below this spine all the
thoracic spines can be palpated along the posterior median line.
The 3rd thoracic spine lies at the roots of spine of scapulae
The 7th thoracic spine lies at inferior angles of the scapulae

8. • SOFTTISSUE LANDMARKS :
1. NIPPLE : in males it usually lies at the 4th intercostal space, its position
varies considerably in females.
2. APEX BEAT : it is visible and palpable cardiac impulse in the left 5th
intercostal space.
3. TRACHEA : it is palpable in the suprasternal notch midway between 2
clavicles.

10. 4. MIDAXILLARY LINE : it passes between 2 folds of axilla, vertically.
5. SCAPULAR LINE : it passes vertically along the inferior angle of scapula.
6. MIDCLAVICULAR LINE : it is a vertical plane passing through the
midinguinal point, the tip of the 9th costal cartilage & middle of the
clavicle.

11. INLET & OUTLET OFTHORAX
• INLET OR SUPERIOR APERTURE :
• BORDERS : anteriorly : upper border of manubrium sterni
posteriorly : superior surface of the body ofT1
on each side : 1st rib with its cartilage.

12. • STRUCTURES PASSINGTHROUGH INLET :
1. Trachea, esophagus, apices of lungs with pleura
2. Brachiocephalic artery on right side & left common carotid and left
subclavian on left side.
3. Phrenic nerves, vagus nerve
4. Sternohyoid, sternothyroid and longus colli

14. • OUTLET OR INFERIOR APERTURE :
• BOUNDRIES : anteriorly : infrasternal angle between 2 costal margins
posteriorly : inferior surface ofT12
on each side : costal margin formed by the cartilages of 7th
to 12th rib.

15. • STRUCTURES PASSINGTHROUGH OUTLET are same as the structures
passing through diaphragm.

17. BONES, JOINTS, & MUSCLES
• BONES : sternum, in the center
ribs, on each side
thoracic vertebrae
• JOINTS : Manubriosternal joint , Costochondral joint
Costovertebral joint, Chondrosternal joint
Costotransverse joint, Interchondral joint

18. GROSS FEATURES
BONE GROSS FEATURES
STERNUM MANUBRIUM, BODY, XIPHOID PROCESS
RIB ANT.END, SHAFT, COSTAL GROOVE, NECK OF
RIB, COSTALTUBERCLE,VERTEBRAL END
THORACICVETEBRAE BODY, VERTEBRAL ARCH,TRANSVERSE
PROCESS, SPINE OFVERTEBRAE

19. MUSCLES
• PECTORAL MUSCLES : 1) Pectoralis major 2) Pectoralis minor
• INTERCOSTAL MUSCLES : 1) External intercostal
2)Internal intercostal
3)Transversus thoracis
a) subcostalis
b)innermost intercostal
c) sternocostalis
• DIAPHRAGM

21. MUSCLE ORIGIN INSERTION
EXTERNAL INTERCOSTAL LOWER BORDER OFTHE RIB ABOVE
THE SPACE
OUTER LIP OFTHE UPPER BORDER OF
THE RIB BELOW
INTERNAL INTERCOSTAL FLOOR OFTHE COSTAL GROOVE OF
THE RIB ABOVE
INNER LIP OFTHE UPPER BORDER OF
THE RIB BELOW
TRANSVERSUSTHORACIS
A) SUBCOSTALIS INNER SURFACE OFTHE RIB NEAR
ANGLE
INNER SURFACE OF 2 OR 3 RIBS
BELOW
B) INNERMOST INTERCOSTAL MIDDLE 2/4TH OFTHE RIDGE ABOVE
GROOVE
INNER LIP OFTHE UPPER BORDER OF
THE RIB BELOW
C) STERNOCOSTALIS 1)LOWER 1/3RD OF POSTERIOR
SURFACE OF BODY OF STERNUM
2)POSTERIOR SURFACE OF XIPHOID
3)POSTERIOR SURFACE OF COSTAL
CARTLIAGE OF LOWER 3 OR4TRUE
RIBS NEAR STERNUM
COSTAL CARTLILAGE OF 2ND TO 6TH
RIB

25. DIAPHRAGM
ORIGIN INSERTION
STERNAL PART : ARISES BY 2 FLESHY SLIPS
FROMTHE BACK OF XIPHOID PROCESS
CENTRALTENDON OFTHE DIAPHRAGM LIES
BELOWTHE PERICARDIUM,THETENDON IS
TILOBAR IN SHAPE, MADE UP OF 3 LEAFLETS
COSTAL PART : ARISES FROM INNER SURFACE
OFTHE CARTILAGE ANDTHE ADJACENT PART
OF LOWER 6 RIB
MIDDLE LEAFLET ISTRIANGULAR,TOWARDS
XIPHOID PROCESS
LUMBAR PART : ARISES FROM MEDIAL AND
LATERAL LUMBOCOSTAL ARCHES& BY RIGHT
AND LEFT CRURA
THE RIGHT AND LEFT LEAFLETS ARETONGUE
SHAPED AND CURVE LATEREALLYAND
BACKWARDS.

27. DIAPHRAGM( openings)
STRUCTURE SITUATION STRUCTURES PASSING
THROUGH
VENA CAVAL T8 IVC, right phrenic
nerve, lymphatics of
liver
OESOPHAGUS T10 Oesophagus, gastric
nerve, oesophageal
vessels
AORTIC T12 AORTA, thoracic duct,
azygos vein

29. DIAPHRAGM
• NERVE SUPPLY : phrenic nerve ( C3, C4,C5)
• ACTION :
1. Principal muscle of inspiration
2. Expulsive acts : sneezing, coughing, laughing, crying, vomiting.

31. PLEURA
• “ It is a closed serous sac which surrounds the lung and invaginated from its
medial side by the root of lung.”
• It has an outer layer, parietal pleura and inner layer, visceral pleura or
pulmonary pleura

33. PULMONARY PLEURA
• It covers the surfaces and fissures of the lung, except at the hilum and
along the attachment of pulmonary ligament.
• It is firmly adherent to the lungs and cannot be separated.
• Surface marking is same as lungs.

35. PARIETAL PLEURA
PART OF PLEURA DESCRIPTION
COSTAL PLEURA LINESTHETHORACICWALLWHICH
COMPRISES RIBS AND INTERCOSTAL
SPACESTO WHICH IT IS LOOSELY
ATTACHED
MEDIASTINAL PLEURA REFLECTEDOVERTHE ROOT OF LUNG
BECOMES CONTINOUSWITH
PULMONARY PLEURAAROUND HILUM
CERVICAL PLEURA COVERSTHE APEX, EXTENDS INTO NECK
DIAPHRAGMATIC PLEURA COVERSTHE BASE OF LUNG

36. SURFACE MARKING PARIETAL PLEURA
REGION EXTENT OF PLEURA
CERVICAL PLEURA EXTENDS INTO ROOT OF NECK, 2.5 CM ABOVE
THE MEDIAL END OF CLAVICLE
ANTERIOR MARGIN 1) SC JOINT 2) MIDPOINT OF STERNAL ANGLE
3)XIPHISTERNAL JOINT
2) SAME FORTHE LEFT SIDE BUT AT 4TH
COSTAL CARTILAGE ARCHES UPWARDS
INFERIOR MARGIN PASSES LATERALLY, CROSSES 8TH RIB
INMIDCLAVICULAR LINE 10TH RIB
INMIDAXILLARY LINE
FURTHER IT PASSES LITTLR BELOW THE 12TH
RIBTOTHE LOWER BORDER OFT12
POSTERIOR MARGIN 2 CM LATERALTOT12 AND A POINT 2 CM
LATERALTO C7.

37. • NERVE SUPPLY : parietal pleura : intercostal & phrenic nerve
pulmonary pleura : autonomic nerves
• BLOOD SUPPLY : intercostal, internal thoracic, musculophrenic arteries
venous drainage into AZYGOS & INTERNALTHORACIC
pulmonary pleura is supplied by bronchial arteries.

38. LUNGS & PLEURA
• SURFACE MARKING OF LUNGS :
• APEX
• ANT. BORDER OFTHE RIGHT LUNG
• ANT. BORDER OFTHE LEFT LUNG
• LOWER BORDER OF EACH LUNG
• POSTERIOR BORDER OF LUNG
• OBLIQUE FISSURE & HORIZONTAL FISSURE
• SURFACE MARKING OF PARIETAL PLEURA

39. GENERAL FEATURE
1. BLUNT APEX
2. BASE resting on diaphragm
3. 3 BORDERS : anterior, posterior, & inferior
4. 2 SURFACES : costal & medial, medial surface divides into vertebral
and mediastinal parts.

40. SURFACE MARKING OF LUNG
• APEX : coincide with the cervical pleura, reaches 2.5 cm above the level of
anterior end of 1st rib, and above the medial 1/3rd of clavicle.
• ANT. BORDER OF RIGHT LUNG : comes in a very close relation with
costomediastinal line of the pleura, it is obtained by joining :
1) A point at SC joint
2) A point in the median plane at the sternal angle
3) A point in the median plane just above the xiphisterenal joint.

41. • ANT. BORDER OF LEFT LUNG : corresponds to the anterior margin of the
pleura up to the level of the 4th costal cartilage. In the lower part it
presents the cardiac notch of variable size.
• LOWER BORDER : lies 2 ribs higher than pleural reflection, it crosses the
6th rib in the midclavicular line, the 8th rib in midaxillary line, 10th rib at the
lateral border of erector spinae muscle, ends at 2 cm lateral toT10.

42. • POSTERIOR BORDER : coincides with the posterior margin of the pleural
reflection except that its lower end lies at the level ofT10.
• OBLIQUE FISSURE : can be obtained by :
1) A point 2 cm lateral toT3
2) Another point on 5th rib in midaxillary line
3) A third point on the 6th costal cartilage 7.5 cm from the median PLANE.

43. • HORIZONTAL FISSURE : can be obtained by :
1) A point on the anterior border on the right lung at the level of the 4th
costal cartilage.
2) A second point on the 5th rib in the midaxillary line.

44. ROOT OF LUNG
• Root is made up of the following structures :
1. Principal bronchus on left side, epartial & hypartial bronchi on right side
2. One pulmonary artery
3. 2 pulmonary veins, superior & inferior
4. Bronchial arteries and bronchial veins
5. Ant & pos pulmonary plexus of nerves
6. Lymphatics of lungs & bronchopulmonary lymph nodes
7. Areolar tissue

45. ARRANGEMENT OF STRUCTURES
1. From anterior to posterior ( similar on both the sides ) :VAB
2. From superior to inferior ( different on 2 sides ) :
right side : BABV
left side : ABV

47. RELATIONS
• ANTERIORLY ON BOTHTHE SIDES: phrenic nerve & pericardiophrenic vessels &
anterior pulmonary plexus
• ON RIGHT SIDE : SVC, right atrium.
• POSTERIORLY ON BOTHTHE SIDES : vagus nerve, posterior pulmonary plexus
• ON LEFT SIDE : descending thoracic aorta
• SUPERIOR : terminal part of azygos vein, arch of aorta
• INFERIOR : pulmonary ligament

48. ARTERIAL,VENOUS, & LYPMPHATIC
DRAINAGE
• ARTERIAL SUPPLY :
• Bronchial arteries supply nutrition to the bronchial tree and to the
pulmonary tissue.
• On the right side, there is one bronchial artery which arises from 3rd right
posterior intercostal artery.
• On the left side, there are 3 bronchial arteries both of which arise from
descending thoracic aorta

49. • VENOUS DRAINAGE :
• Venous blood from the 1st & 2nd divisions of bronchi is carried by bronchial
veins.
• There are 2 bronchial veins on each side, the right bronchial veins drain
into azygos vein.
• The left bronchial vein drains into hemiazygos vein.

50. • LYPMPHATIC DRAINAGE :
• There are 2 sets of lymphatics, both of which drains into
bronchopulmonary nodes.
• Superficial vessels drain the peripheral lung tissue lying beneath the
pulmonary pleura.
• Deep lymphatics drain the bronchial tree, the pulmonary vessels and
connective tissue septa.

51. • NERVE SUPPLY :
• Parasympathetic nerves are derived from vagus( motor, sensory,
secretomotor fibers)
• Sympathetic nerves are derived from 2nd to 5th sympathetic ganglia.These
are inhibitory to smooth muscles and glands.