Lecture 3 lungs & pleura

27,724 views

Published on

by Dr. Noura El Tahawy, Faculty of Medicine, El Minia University

Published in: Health & Medicine
0 Comments
33 Likes
Statistics
Notes
  • Be the first to comment

No Downloads
Views
Total views
27,724
On SlideShare
0
From Embeds
0
Number of Embeds
240
Actions
Shares
0
Downloads
969
Comments
0
Likes
33
Embeds 0
No embeds

No notes for slide

Lecture 3 lungs & pleura

  1. 1. Lungs & pleura By Dr. Noura El Tahawy MD., Ph.D., Faculty of Medicine, El Minia Universitywww.slideshare.net/drnosman
  2. 2. Cross-section of the thorax showing the position of the mediastinum, lungs & pleural cavities .
  3. 3. Subdivisions of the mediastinum.
  4. 4. Pleura
  5. 5. Pleural cavity• The two pleural cavities are situated on either side of the mediastinum• Each pleural cavity is completely lined by a mesothelial membrane called the pleura.• The outer surface of each lung is covered by pleura• Each lung remains attached to the mediastinum by a root formed by the airway, pulmonary blood vessels, lymphatic tissues, and nerves.• The pleura lining the walls of the cavity is the parietal pleura, whereas that reflected from the mediastinum at the roots and onto the surfaces of the lungs is the visceral pleura.• Only a potential space normally exists between the visceral pleura covering lung and the parietal pleura lining the wall of the thoracic cavity• The lung does not completely fill the potential space of the pleural cavity, resulting in recesses, which do not contain lung and are important for accommodating changes in lung volume during breathing.• The costodiaphragmatic recess, which is the largest and clinically most important recess, lies inferiorly between the thoracic wall and diaphragm .
  6. 6. Formation of pleuralcavity during lungdevelopment
  7. 7. Cross-section of the thorax showing the position of the mediastinum, lungs & pleural cavities .
  8. 8. Parietal pleural reflections and recesses.
  9. 9. Pleuralcavities.
  10. 10. Lateral view of the upperopening of the thoracic cageshowing how the apex of thelung projects superiorly into theroot of the neck. The apex of thelung is covered with visceral andparietal layers of pleura and isprotected by the suprapleuralmembrane, which is athickening of the endothoracicfascia .
  11. 11. Section through anintercostal space .B .Structures penetrated bya needle when it passesfrom skin surface to pleuralcavity. Depending on thesite of penetration, thepectoral muscles will bepierced in addition to theserratus anterior muscle .
  12. 12. Lungs Dr. Noura El Tahawy
  13. 13. Surfaces & borders of the lungs• Each lung has a half-cone shape, with a base, apex, two surfaces and three borders• The base sits on the diaphragm .• The apex projects above rib I and into the root of the neck .• The two surfaces-the costal surface lies immediately adjacent to the ribs and intercostal spaces of the thoracic wall. The mediastinal surface lies against the mediastinum anteriorly and the vertebral column posteriorly and contains the comma-shaped hilum of the lung through which structures enter and leave .• The three borders-the inferior border of the lung is sharp and separates the base from the costal surface. The anterior and posterior borders separate the costal surface from the medial surface. Unlike the anterior and inferior borders, which are sharp, the posterior border is smooth and rounded .
  14. 14. Lungs.
  15. 15. Root& hilum of the lung• In the mediastinum, the vagus nerves pass immediately posterior to the roots of the lungs, while the phrenic nerves pass immediately anterior to them. There is a thin blade-like fold of pleura projects inferiorly from the root of the lung and extends from the hilum to the mediastinum. This structure is the pulmonary ligament• Within each root and located in the hilum are :• a pulmonary artery ;• two pulmonary veins ;• a main bronchus ;• bronchial vessels ;• nerves; and lymphatics• Generally, the pulmonary artery is superior at the hilum, the pulmonary veins are inferior, and the bronchi are somewhat posterior in position .• On the right side, the lobar bronchus to the superior lobe branches from the main bronchus in the root, unlike on the left where it branches within the lung itself, and is superior to the pulmonary artery .
  16. 16. Roots and hila of the lungs.
  17. 17. A. Right lung.
  18. 18. B. Major structuresrelated to the right lung(mediastinal surface).•These include :•the heart (Rt atrium)• inferior vena cava,•superior vena cava• esophagus .• right subclavianartery and vein archover and are relatedto the superior lobe ofthe right lung as theypass over the dome ofcervical pleura andinto the axilla .
  19. 19. A. Left lung.
  20. 20. B. Major structuresrelated to the leftlung (mediastinalsurface).•These include:•the heart (Lt. ventricle),•aortic arch•Descending thoracicaorta•esophagus.•left subclavian arteryand vein arch over andare related to thesuperior lobe of the leftlung as they pass overthe dome of cervicalpleura and into theaxilla.
  21. 21. Bronchial tree&Broncho-pulmonary Segments
  22. 22. Bronchial tree• Bronchial tree: Trachea is a flexible tube that extends from vertebral level CVI in the lower neck to vertebral level T4 in the mediastinum where it bifurcates into a right and a left main bronchus .• The trachea is held open by C-shaped transverse cartilage rings embedded in its wall-the open part of the C facing posteriorly. The posterior wall of the trachea is composed mainly of smooth muscle .Each main bronchus enters the root of a lung and passes through the hilum into the lung itself. The right main bronchus is wider and takes a more vertical course through the root and hilum than the left main bronchus . Therefore, inhaled foreign bodies tend to lodge more frequently on the right side than on the left.• The main bronchus divides within the lung into lobar bronchi (secondary bronchi), each of which supplies a lobe. On the right side, the lobar bronchus to the superior lobe originates within the root of the lung. The lobar bronchi further divide into segmental bronchi (tertiary bronchi), which supply bronchopulmonary segments.• Within each bronchopulmonary segment, the segmental bronchi give rise to multiple generations of divisions and, ultimately, to bronchioles, which further subdivide and supply the respiratory surfaces. The walls of the bronchi are held open by discontinuous elongated plates of cartilage, but these are not present in bronchioles.
  23. 23. A. Bronchial tree. B. Bronchopulmonary segments.
  24. 24. Bronchopulmonary segments• bronchopulmonary segment is the area of lung supplied by a segmental bronchus and its accompanying pulmonary artery branch .Tributaries of the pulmonary vein tend to pass intersegmentally between and around the margins of segments.• Each bronchopulmonary segment is shaped like an irregular cone with the apex at the origin of the segmental bronchus and the base projected peripherally onto the surface of the lung .• Clinical note: A bronchopulmonary segment is the smallest, functionally independent region of a lung and the smallest area of lung that can be isolated and removed without affecting adjacent regions.• There are ten bronchopulmonary segments in each lung (some of them fuse in the left lung)
  25. 25. A. Bronchial tree. B. Bronchopulmonary segments.
  26. 26. Bronchopulmonary segments. A. Right lung. B. Left lung.(Bronchopulmonary segments are numbered and named)
  27. 27. Bronchopulmonary segments. A. Right lung. B. Left lung.(Bronchopulmonary segments are numbered and named)
  28. 28. Blood supply of the lungsBronchial arteries and veinsThe bronchial arteries and veins constitute the nutritive vascular system of the pulmonary tissues (bronchial walls and glands, walls of large vessels, and visceral pleura).The bronchial arteries originate from the thoracic aorta or one of its branches :1. a single right bronchial artery normally arises from the third posterior intercostal artery (but occasionally, it originates from the upper left bronchial artery2. two left bronchial arteries arise directly from the anterior surface of the thoracic aorta: -the superior left bronchial artery arises at vertebral level TV, and the inferior one inferior to the left bronchus .The bronchial arteries run on the posterior surfaces of the bronchi and ramify in the lungs to supply pulmonary tissues .The bronchial veins drain into :either the pulmonary veins or the left atrium; andinto the azygos vein on the right or into the superior intercostal vein or hemiazygos vein on the left .
  29. 29. Pulmonary vessels. A. Diagram of an anterior view. B. Axial computedtomography image showing the left pulmonary arterybranching from the pulmonary trunk.C. Axial computedtomography image(just inferior to the image in B) showing the right pulmonary arterybranching from the pulmonary trunk.
  30. 30. Pulmonary innervation
  31. 31. Lymphatic drainage of lungs.
  32. 32. Surface anatomy of the lungs & pleura
  33. 33. Surface anatomy of the lungs• The apex of the lung projects into the neck. It can be mapped out on the anterior surface of the body by drawing a curved line, convex upward, from the sternoclavicular joint to a point 1 in. (2.5 cm) above the junction of the medial and intermediate thirds of the clavicle• The anterior border of the right lung begins behind the sternoclavicular joint and runs downward, almost reaching the midline behind the sternal angle. It then continues downward until it reaches the xiphisternal joint• The anterior border of the left lung has a similar course, but at the level of the fourth costal cartilage it deviates laterally and extends for a variable distance beyond the lateral margin of the sternum to form the cardiac notch . This notch is produced by the heart displacing the lung to the left. The anterior border then turns sharply downward to the level of the xiphisternal joint.• The lower border of the lung in midinspiration follows a curving line, which crosses the 6th rib in the midclavicular line and the 8th rib in the midaxillary line, and reaches the 10th rib adjacent to the vertebral column posteriorly. It is important to understand that the level of the inferior border of the lung changes during inspiration and expiration.• The posterior border of the lung extends downward from the spinous process of the 7th cervical vertebra to the level of the 10th thoracic vertebra and lies about 1.5 in. (4 cm) from the midline• The oblique fissure of the lung can be indicated on the surface by a line drawn from the root of the spine of the scapula obliquely downward, laterally and anteriorly, following the course of the sixth rib to the sixth costochondral junction. In the left lung the upper lobe lies above and anterior to this line; the lower lobe lies below and posterior to it.• In the right lung is an additional fissure, the horizontal fissure ,which may be represented by a line drawn horizontally along the fourth costal cartilage to meet the oblique fissure in the midaxillary line. Above the horizontal fissure lies the upper lobe and below it lies the middle lobe; below and posterior to the oblique fissure lies the lower lobe.
  34. 34. Surface anatomy of the pleura• The boundaries of the pleural sac can be marked out as lines on the surface of the body. The lines, which indicate the limits of the parietal pleura where it lies close to the body surface, are referred to as thelines of pleural reflection.• The cervical pleura bulges upward into the neck and has a surface marking identical to that of the apex of the lung. A curved line may be drawn, convex upward, from the sternoclavicular joint to a point 1 in. (2.5 cm) above the junction of the medial and intermediate thirds of the clavicle• The anterior border of the right pleura runs down behind the sternoclavicular joint, almost reaching the midline behind the sternal angle. It then continues downward until it reaches the xiphisternal joint. Theanterior border of the left pleura has a similar course, but at the level of the fourth costal cartilage it deviates laterally and extends to the lateral margin of the sternum to form the cardiac notch. (Note that the pleural cardiac notch is not as large as the cardiac notch of the lung.) It then turns sharply downward to the xiphisternal joint• The lower border of the pleura on both sides follows a curved line, which crosses the 8th rib in the midclavicular line and the 10th rib in the midaxillary line, and reaches the 12th rib adjacent to the vertebral column—that is, at the lateral border of the erector spinae muscle Note that the lower margins of the lungs cross the 6th, 8th, and 10th ribs at the midclavicular lines, the midaxillary lines, and the sides of the vertebral column, respectively; the lower margins of the pleura cross, at the same points, the 8th, 10th, and 12th ribs, respectively. The distance between the two borders corresponds to the costodiaphragmatic recess .
  35. 35. Surface markings of lungs and parietal pleura on the anterior thoracic wall
  36. 36. Surface markings of the lungs and parietal pleura on the posterior thoracic wall .
  37. 37. Surface markings of the lungs and parietal pleura on the lateral thoracic walls .
  38. 38. Bronchoscopy• Patients who have an endobronchial lesion (i.e. a lesion within a bronchus) may undergo bronchoscopic evaluation of the trachea and its main branches. The bronchoscope is passed through the nose into the oropharynx and is then directed by a steerable control system past the vocal cords into the trachea. The bronchi are inspected and, if necessary, small biopsies are obtained.
  39. 39. Bronchoscopic evaluation.A. Of the lower end of the trachea and its main branches. B. B. Of tracheal bifurcation showing a tumor at the carina.
  40. 40. Bronchoscopic evaluation. A. Of thelower end of the trachea and its main branches. B. Of tracheal bifurcation showing a tumor at the carina.
  41. 41. Reviews
  42. 42. Cross-section of the thorax showing the position of the mediastinum.
  43. 43. Lateral view of the mediastinum.
  44. 44. Subdivisions of the mediastinum.
  45. 45. Questions• Mention the surface anatomy of the lungs & pleura• Give an account on the anatomy of broncho-pulmonary segments& their clinical importance• Give an account on the relations of the medial surface of the Right lung• Give an account on the relations of the medial surface of the Left lung• Complete the following statements; --- Nerve supply of the parietal pleura is ………….…, while that of pulmonary (visceral) pleura is ………. ------ The root of the lung lies opposite …, ….., ….... Vertebrae. ---- The structures passing through the hilum of the lung are: 1 ………….. 2 ……………..3 ………….4 …………… 5 ………………6……….. -----The arterial supply of the lung is derived from ……………………artery, which is a branch from ………... …. In the right lung & from …………………..…… in the left lung ____ The pulmonary veins drain into …………….. while the bronchial veins drain into ……….
  46. 46. Thank you

×