This document provides an overview of the anatomy of the lungs, pleura, and diaphragm. It describes the structure and function of the lungs including lobes and fissures. It discusses the pleura, its layers and reflections. It also details the origins, parts and functions of the diaphragm. Throughout it includes labeling of diagrams to enhance understanding of respiratory structures.

1. Clinical Anatomy of lungs , pleura
and diaphragm
Dr. Ashish kumar
Dept. of Chest & T.B, Santosh university

2. Points
1. Basic anatomy of respiratory system
2. Surface anatomy
3. Blood circulations
4. Innervations
5. Lymphatic
6. Basic anatomy of pleura
7. Basic anatomy of diaphragm

3. Respiratory System starts at the nares
Major Functions
Upper respiratory system:
1. Air conditioning (warming)
2. Defense against pathogens
3. Gas Transport
Lower respiratory system:
1. Speech & other respiratory
sounds
2. Gas exchange (ventilation)
3. Maintenance of homeostasis, e.g.
pH

4. Respiratory Muscles
Diaphragm: depresses on contraction  inhalation
External intercostals: elevate ribs  inhalation
Internal intercostals: depress ribs  active exhalation
(Accessory muscles - serratus anterior, scalenes, pectoralis minor,
sternocleidomastoid, internal and external obliques, transverse
abdominus, rectus abdominus)

9. Upper Respiratory System
1. Nose
2. Nasal Cavity
3. Paranasal sinuses
4. Pharynx

10. Upper Respiratory
System
1) Nose
 External and internal nares =
Nostrils
 Nose Hairs = vibrissae
 Alar cartilages on the nose
 Paranasal Sinuses

11. Upper Respiratory
System
• 2) Nasal Cavity
• Nasal Conchae:
– Superior, middle and
inferior
– Other name: “Turbinate
bones” because they create

12. Upper Respiratory
System
3)Paranasal Sinuses
• Named after their bones
– Frontal
– Ethmoid
– Sphenoid
– Maxillary

13. Upper Respiratory
System
4) Pharynx
Shared passageway for respiratory and digestive systems
Nasopharynx - part above uvula and posterior to internal nares
Oropharynx – portion visible in mirror when mouth is wide open
fauces = the opening
uvula - posterior edge of soft palate
Laryngopharynx – between the hyoid bone & the esophagus

15. Larynx (voice box)
 The larynx consists of three
articulating cartilages,
1. Thyroid
2. cricoid
3. Arytenoid

16. Lungs
 Light, soft, spongy
 Conical in shape, apex, base, costal surface, medial surface, hilus.
Note various impressions
 Right lung
 Three lobes; superior, middle and inferior
 Oblique and horizontal fissure
 Left Lung
 Two lobes; superior and inferior also Lingula and Cardiac notch, oblique
fissure

17. Right Lung

18. Left Lung

19. Right Lung

20. Lung Fissures:
Oblique fissure (Right & Left):
It starts at the 3rd thoracic spine while the arms are elevated, descends
downwards, laterally & anteriorly along the medial border of the scapula
touching the inferior angle of the scapula) cutting the midaxillary line in
the 5th rib & ending at the 6th costal cartilage 3 inches from the midline.
In cadaver it arise at the 2nd thoracic spine.
The transverse fissure (Right):
It arises at the 4th costal cartilage, runs horizontally to meet the oblique
fissure in the midaxillary line in the 5th rib.

21. Fissures & Lobes of the Lungs

22. Fissures & Lobes of the Right Lung

23. Right Upper Lobe

24. Right Middle Lobe

25. Right Lower lobe

26. Left Lung

27. Fissures of the Left Lung

28. Left Upper Lobe

29. Left Lower Lobe

30. Airways
 Trachea, primary bronchi, secondary bronchi, tertiary bronchi out
to 25 generations( terminal bronchiols)
 All comprised of hyaline cartilage
 Trachea
 Begins where larynx ends (about C6)
 10-12 cm long, half in neck, half in mediastinum
 20 U-Shaped rings of hyaline cartilage – keeps lumen intact but not as
brittle as bone
 Lined with epithelium and cilia which work to keep foreign
bodies/irritants away from lungs

31. From Bronchi to Lungs: The Bronchial Tree
 1 bronchi (enter lungs at hilus,
complete cartilage rings)
 2 bronchi (from now on cartilage
plates)
 3 bronchi
 Bronchioles
 Terminal bronchioles
 Respiratory bronchioles
 Alveolar ducts
 Alveolar sacs
Conducting
portion
Respiratory portion

32. Airways
 Primary Brochi One to each lung – continuation of trachea
 Right bronchus is wider and shorter 2.5 cm as opposed to 5 cm
and branches from the trachea at a greater angle
 Secondary bronchi – one to each lobe, three in right, two in
left
 Tertiary – one to each bronchopulmonary segment –
approximately 10 per lung
 All of the above are hyaline cartilage with no ability to
change diameter

35. Bronchopulmonary Segments

36. Bronchopulmonary Segments

37. Bronchopulmonary Segments

38. Bronchioles
 First level of airway surrounded by smooth muscle
(not the cartilage ), therefore can change diameter as
in brocho-constriction and broncho-dilation
 Terminal
 Respiratory
 3-8 orders
 alveoli

39. Bronchioles

40. Surface Anatomy

41. Borders of the lung:
• The apex is about 2-3 cms (1 inch) above the medial 1/3 of the
clavicle, then the anterior border of both lungs run downwards &
medially meeting each other in the middle line behind the angle of
Louis (sternal angle).
• The anterior border of right lung continues running downwards till
the 6th costochondral junction.
• The anterior border of left lung continues running downwards till
the 4th costal cartilage then curves laterally ½ inch forming the
cardiac notch then descends downwards till the 6th costochondral
junction.

42. Borders of the lung:
• The lower border of the lungs represented by a line starting
from 6th rib in the MCL, 8th rib in the MAL & 10th rib in the
scapular line.

43. Circulation of lungs
Two types
1. Bronchial circulation
2. Pulmonary circulation

44. Bronchial circulation
• The trachea (and esophagus), main-stem bronchi, and pulmonary
vessels into the lung , as well as the visceral pleura in humans are
supplied by the bronchial (systemic) circulation.
• The bronchial circulation has enormous growth potential. In long-
standing inflammatory and proliferative diseases, such as
bronchiectasis or carcinoma, bronchial blood flow may be greatly
increased.

45. Pulmonary circulation
• In humans the pulmonary artery enters each lung at the hilum in a
loose connective tissue sheath adjacent to the main bronchus.
• The pulmonary artery travels adjacent to and branches with each
airway generation down to the level of the respiratory bronchiole.
• As blood enters the vast alveolar wall capillary network, its velocity
slows, averaging approximately 1000 µm/sec (or 1 mm/sec),where
gas exchange take place.

46. • Anatomically, the pulmonary blood vessels can be divided into two
groups in
1. Extra-alveolar
2. Alveolar.
 Extra-alveolar
vessels lie in the loose-binding connective tissue (peribronchovascular
sheaths, interlobular septa). Extra-alveolar vessels extend into the
terminal respiratory units. Arteries as small as 100 µm in diameter
have loose connective tissue sheaths. This is in contrast to the
bronchioles, which are tightly embedded in the lung framework from
the bronchioles (1 mm in diameter) onward.
 Alveolar vessels
lie within the alveolar walls and are embedded in the parenchymal
connective tissue

47. Innervation
 Pleura via intercostal (thoracic) nerves.
 Tracheobronchial tree motor pathway
 Parasympathetic via CN X efferent function = broncho-
constriction via smooth muscle, also to epithelial cells in
trachea, afferent = responsible for cough reflex
 Sympathetic from T1-T5 efferent = brocho-dilation

48. • Cholinergic, adrenergic, and peptidergic nerve Endings are
present around tracheal glands and do not show patterns of
slective innervation density between serous and mucous
cells . Serous and mucous granule secretion is stimulated
more by muscarinic than by adrenergic agents.

49. lymphatics
• Superficial plexuses- The superficial plexus is located n the
surface of the lung just beneath the pulmonary pleura.
• Deep plexuses-accompanies the branches of the pulmonary
vessels and ramifications of bronchi.

50. Right lung lymphatics
• Right upper lobe:
• Upper 2/3rd-Right tracheobronchial nodes
• Lower l/3rd -Dorsolateral hilar nodes
• Right middle lobe:
• Hilar nodes around middle lobe bronchus
• Right lower lobe:
• Porsolateral part-Dorsolateral hilar nodes
• Ventromedial part- Ventromedial hilar and carinal nodes

51. Left lungs lymphatics
• Left upper lobe:
• Apex-para-aortic node
• Other than apex-Anterior and posterior hilar nodes
• Left lower lobe
• Dorsolateral part-Dorsolateral hilar nodes
• Ventromedial par^Ventromedial hilar and carinal nodes

52. Pleura
• Visceral pleura:
Covers and follows indentations of lung.
• Parietal pleura:
Lines thoracic cavity.

53. Parietal Pleura Divisions
• Costal pleura lines the ribs.
• Diaphragmatic pleura covers the diaphragm.
• Mediastinal pleura lies against the mediastinum.
• Cervical pleura extends above the level of the first
rib.

54. Pleural Reflections
• Costodiaphragmatic recess (space):
Space where costal and diaphragmatic pleura
meet.
• Costomediastinal recess (space):
Space where mediastinal and costal pleura meet.
• Pulmonary ligament:
Transition between visceral and parietal pleura at
root of the lung.

55. Pleural Lines of Reflection
• Cervical dome of pleura:
Anteriorly, 1.5-2.5 cm above the sternal end of
the clavicle.
Anterior margin extends obliquely behind the
sternoclavicular joint.
At sternal angle, the pleura is at the median line and
two sides stay in contact until the fourth costal cartilage.

56. Pleural Lines of Reflection
• Right side:
– Leaves sternum at 7th
costal cartilage.
– At 8th costal cartilage at
midclavicular line.
– At 10th rib at axillary line.
– At 11th rib at scapular line.
– Extends to level of body
of T12 and then
ascends.

57. Pleural Lines of Reflection
• Left side:
– Leaves sternum at IC
space 5.
– 1.5 cm from sternal
margin at 6th costal
cartilage.
– Follows same landmarks
as right side from this
point.

58. Diaphragm
• The diaphragm is a curved musculo fibrous sheet that
separates the thoracic from the abdominal cavity.
• pierced by structures that pass between these two
regions of the body.
• primary muscle of respiration.
• dome shaped and consists of a peripheral muscular
part and central tendinous part.

59. • muscular part arises from the margins of the
thoracic opening and gets inserted into the
central tendon.
• attachments to the thoracic wall are low
posteriorly and laterally, but high anteriorly.
• Rarely affected by intrinsic diseases
• complex embryological development is subject
to number of congenital anomalies

60. Origin of the diaphragm
• sternal part- arising from the posterior surface
of the xiphoid process.
• costal part arising from the deep surfaces of the
lower six ribs and their costal cartilages & forms
the right & left domes.
• vertebral/lumbar part arising from upper three
lumbar vertebrae; forms the right & left crura &
the arcuate ligaments.

61. • Crura:The right
crura is from the
bodies of first three
lumbar vertebrae.
• The left crus, from
the bodies of first
two lumbar
vertebrae.

62. • Arcuate ligaments:Lateral to the crura on both
sides.
• Medial arcuate ligament is thickened upper
margin of fascia that covers the psoas muscle.
• Lateral arcuate ligament is thickened upper
margin of the fascia covering the quadratus
lumborum muscle.

63. Parts of the Diaphragm
• It is studied as
(a)Central tendon
(b)Right & left crus
(c)Right & left dome

64. Functions of the Diaphragm
1. Muscle of inspiration: On contraction the diaphragm pulls
its central tendon down and increases the vertical
diameter of the thorax. The diaphragm is the most
important muscle used in inspiration.
2. Muscle of abdominal straining: The contraction of the
diaphragm assists the contraction of the muscles of the
anterior abdominal wall in raising the intra-abdominal
pressure for micturition, defecation, and parturition.

65. 3. Weight lifting muscle: In a person taking a deep breath and
holding it (fixing the diaphragm), the diaphragm assists the
muscles of the anterior abdominal wall in raising the intra-
abdominal pressure.
4. Thoraco-abdominal pump: The descent of the diaphragm
decreases the intrathoracic pressure & increases the intra-
abdominal pressure.
This compresses the blood
in the inferior vena cava
and forces it upward into
the right atrium of the
heart.
Within the abdominal
lymph vessels is also
compressed, and its passage
upward within the thoracic
duct is aided by the negative
intrathoracic pressure.

66. 8
10
12

68. Other minor openings
• Sympathetic trunk (pass posterior to the medial
arcuate ligament on both sides).
• Superior epigastric vessels (pass between the
sterna and costal origins of the diaphragm on
each side).

69. • Left phrenic nerve (pierces the left dome
of diaphragm)
• Neurovascular bundles of lower six intercostal spaces
(pass between the muscular slips of costal origin of
diaphragm)

70. Vascular supply
• Lower five intercostal and subcostal arteries- supply
the costal margins of the diaphragm
• Phrenic arteries- supply the main central portion of
the diaphragm.
• The phrenic veins follow the corresponding arteries
on the inferior diaphragmatic surface.

72. Nerve supply of diaphragm
• sensory supply of the central tendon of diaphragm
that is covered by parietal and peritoneal pleura is
from phrenic nerve.
• Sensory supply to the periphery of diaphragm is
from lower six intercostal nerves.
• The motor nerve supply of diaphragm is only from
the phrenic nerve.

74. Phrenic nerve
• descends anterior to the pulmonary hilum, between the
fibrous pericardium and mediastinal pleura, to the
diaphragm, accompanied by the pericardiophrenic
vessels.
• supplies sensory branches to the mediastinal pleura,
fibrous pericardium and parietal serous pericardium.
• The right phrenic nerve is shorter and more vertical than
the left