Anatomy of lungs, pleura and diaphragm

Anatomy of lungs, pleura and diaphragm

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

2. Points Basic anatomy of respiratory system Surface anatomy Blood circulations Innervations Lymphatic Basic anatomy of pleura Basic anatomy of diaphragm

3. Respiratory System starts at the nares Major Functions Upper respiratory system: Air conditioning (warming) Defense against pathogens Gas Transport Lower respiratory system: Speech & other respiratory sounds Gas exchange (ventilation) 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 )

5. Upper Respiratory System Nose Nasal Cavity Paranasal sinuses Pharynx

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

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

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

9. Upper Respiratory System 4) Pharynx S hared 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

10. Larynx (voice box) The larynx consists of three articulating cartilages, Thyroid cricoid Arytenoid

11. 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

12. Right Lung

13. Left Lung

14. Right Lung

15. Lung Fissures: Oblique fissure (Right & Left): It starts at the 3 rd 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 5 th rib & ending at the 6 th costal cartilage 3 inches from the midline. In cadaver it arise at the 2 nd thoracic spine. The transverse fissure (Right): It arises at the 4 th costal cartilage , runs horizontally to meet the oblique fissure in the midaxillary line in the 5 th rib.

16. Fissures & Lobes of the Lungs

17. Fissures & Lobes of the Right Lung

18. Right Upper Lobe

19. Right Middle Lobe

20. Right Lower lobe

21. Left Lung

22. Fissures of the Left Lung

23. Left Upper Lobe

24. Left Lower Lobe

25. 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

26. 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

27. 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

28. Bronchopulmonary Segments

29. Bronchopulmonary Segments

30. Bronchopulmonary Segments

31. 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

32. Bronchioles

33. Surface Anatomy

34. 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 6 th costochondral junction. The anterior border of left lung continues running downwards till the 4 th costal cartilage then curves laterally ½ inch forming the cardiac notch then descends downwards till the 6 th costochondral junction .

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

36. Circulation of lungs Two types Bronchial circulation Pulmonary circulation

37. 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.

38. 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.

39. Anatomically, the pulmonary blood vessels can be divided into two groups in Extra-alveolar 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

40. 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

41. 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.

42. 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.

43. Right lung lymphatics Right upper lobe: Upper 2/3 rd -Right tracheobronchial nodes Lower l/3 rd - 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

44. 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

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

46. 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 .

47. 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.

48. 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.

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

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

51. 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.

52. 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

53. 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.

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

55. 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.

56. Parts of the Diaphragm It is studied as Central tendon Right & left crus Right & left dome

57. Functions of the Diaphragm 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. 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.

58. 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. 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.

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60. 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).

61. 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)

62. 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.

63. 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 .

64. 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

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