This document provides an overview of how to interpret a normal chest x-ray by describing the anatomical structures that should be visualized and what is considered normal for each structure. It discusses evaluating the bony thorax, soft tissues, mediastinum, lungs and diaphragm and how they change with age from infancy to childhood to older age. Key anatomical structures and their expected appearance on a normal chest x-ray are defined.

1. The Normal Chest http://crisbertcualteros.page.tl

2. General Considerations in Chest Interpretation

3. Developing the interpretative skills begins by looking at as many normal films as possible to develop an eye for the normal range…………

5. Objectives To be familiar with the normal chest roentgenogram Identify anatomical structures Know deviations from normal

6. Structures Visualized

7. Inspect mediastinum heart and great vessels trachea and central bronchi lungs and diaphragm bony thorax and soft tissue of thorax and neck

8. Note: compare lungs interspace by interspace

9. Remember make the initial examination of the film without knowledge of the clinical findings But before making a decision, xray observations must be correlated with all available clinical findings

10. Patterns of Pulmonary Opacity Alveolar or Air Space Pattern char by homogenous opacity Interstitial Pattern char by an increased prominence of the perivascular, interlobular and parenchymal interstitial spaces

11. First things first… Patient's name Date exam done Check for position markers

12. Other things to check.. Patient’s position Type of film Technical quality of the film

13. INITIAL SURVEY General Body Size, Shape, and Symmetry Male vs. Female Is this an infant, child, young adult, elderly person? Survey for foreign objects - tubes, IV lines, EKG leads, surgical drains, prosthesis, etc., as well as non-medical objects, bullets, shrapnel, glass, etc.

14. The Adult Chest

15. Bony Thorax Shoulder girdles Ribs Cervical vertebrae Thoracic vertebrae Clavicles Scapulae

16. What is normal? Age Body habitus Angulation of the ribs Hyperesthenic--- minimal Asthenic------- maximal

17. Bony Thorax ICS are numbered according to the rib above them. Anterior vs. posterior

18. Costal cartilage not calcified Calcification- mottled appearance men- peripheral women- central

19. Rhomboid Fossa anatomic variant of no clinical significance

20. SOFT TISSUES produce shadow on chest x-ray skin folds produce linear shadows in any direction breast shadow increased opacity over the lower thorax nipple shadows-round opacity in 4th anterior interspace or lower metallic nipple markers

21. Nipple Shadow Breast Shadow

22. produced by skin and ST over clavicles 2-3 mm to 1 cm projects beyond the lungs Clavicular Companion Shadow

23. Nodules and ST Masses may simulate pulmonary nodules subQ or deeper tissues of thoracic wall--->more sharply defined than intrapulmonary lesions CT scan if unsure

24. Mediastinum the space lying between the right and left pleurae in and near the median sagittal plane of the chest

25. Anatomic Division and Contents post aspect of the sternum to anterior aspect of thoracic vertebrae contains all thoracic viscera exept lungs

26. Divisions A- anterior B- middle C- post

27. Anterior Mediastinum aka: prevascular space above: thoracic inlet lat: pleura ant: sternum post: pericardium and great vessels contents: loose areolar tissue, LN, lymphatic vessels

28. Middle Mediastinum aka: vascular space ant: anterior mediastinum post: post mediastium contains the heart and the pericardium, ascending and transverse arch of the aorta, SVC, azygos, brachiocephalic vein and arteries and phrenic nerves upper vagus nerves, trachea and its bifurcation, the main bronchi, pulmo artery and branches, pulmo veins, lymph nodes

29. Posterior Mediastinum aka: post vascular space lies behind the heart and pericardium extends from the level of the thoracic inlet to the 12th thoracic vertebra contents: thoracic portion of the descending aorta, esophagus, thoracic duct, azygos and hemi azygos veins, lymph nodes, sympathetic chains and inferior vagus nerves.

30. Mediastinal Pleural Reflections

31. Anterior Junction Line anterior to trachea, behind sternum from sternal angle downward and to the left represents the apposition of the visceral and parietal pleura of the upper lobes projected over the trachea as thin linear shadow, convex to the left

32. Posterior Junction Line post to trachea and esophagus from the thoracic inlet downward to level of the azygos and aortic arches represents the approximation of visceral and parietal pleura of the upper lobes posteriorly projects over the tracheal air shadow and is convex to the left

33. Azygoesophageal Recess extends from the inferior surface of the azygos arch downward and to the left to level of the diaphragm outlines medial aspect of the right lower lobe and right lateral aspect of the esophagus concave on its right

34. Right Paratracheal Stripe consists of the right lateral tracheal wall and adjacent parietal and visceral pleura of the right upper lobe. widened or altered by tracheal mediastinal and pleural disease

35. Paraspinal Interphase (pleural reflection) right side- posteriorly between parietal pleura and lateral aspect of thoracic vertebrae left side- left lateral wall of the descending aorta with lung

36. Lymph Nodes Anterior mediastinal (prevascular) Paratracheobronchial

37. Normal nodes are small and cannot be identified on normal chest radiographs

38. Anterior Mediastinal (prevascular) R: ant to SVC and R innominate vein L: anterior to aorta and carotid artery Ductus Nodes lie ant to ligamentum arteriosum in the aortopulmonary window

39. Paratracheobronchial Paratracheal Subcarinal (bifurcation) Hilar

40. Trachea A band of radiolucency in the midline Very slight deviation to the RIGHT at level of aortic arch Extends from C6 to T5 then divides

42. The angle formed by the bronchi with the sagittal plane is equal bilaterally until 15yo Tracheal deviation to the right increases the angle on the left Subcarinal angle = 60 0 Nice to know………….

43. Right Main Bronchi More vertical than left 2 primary branches Eparterial bronchus Hyparterial bronchus

44. Left Main Bronchi longer, deviates more laterally than right Divides into Lower lobe bronchus Left upper lobe bronchus

45. Aortic Nipple left superior intercostal, vein seen in cross section as it courses around the aorta

46. local concavity or notch between the aortic arch and the pulmonary artery Aortopulmonary Window

47. HILUM Contains the Pulmonary arteries and veins Bronchi Bronchial arteries and veins Lymph nodes

48. Hilar Height Ratio Useful in determining relative volume gain or loss in lower vs. upper lobes Height above hilum Height below hilum Right=1.3 Left= 0.84

49. CT of the Mediastinum

50. Relationships at the level of the origin of the three branches of the aortic arch

52. Origin of the three branches of the Aortic Arch The esophagus -anterior to and slightly to the left of the body of a thoracic vertebra. The trachea is anterior to and slightly to the right of the esophagus. The brachiocephalic artery, left common carotid artery, and left subclavian artery each appears in transverse section. The thymus (if present) casts a triangular image directly anterior to the left brachiocephalic vein.

53. Level of the aortic-pulmonary window

55. Esophagus lies directly anterior to and to the left of the body of a thoracic vertebra. The main stem bronchi appear in oblique section just above or below the level of the carina. The azygos vein appears at the level where it arches over the right main stem bronchus and ends via union with the superior vena cava The region in the scan between the origin and end of the aortic arch represents the aortic pulmonary window. Level of the aortic-pulmonary window

56. Level of the roots of the ascending aorta and pulmonary trunk

58. The azygos vein, esophagus, and descending thoracic aorta all appear in the posterior mediastinum. Lobar or segmental bronchi lie on either side of the oblate outline of the left atrium. The roots of the ascending aorta and pulmonary trunk lie directly anterior to the left atrium. A crescent-shaped right atrium lies directly to the right of the root of the ascending aorta. Level of the roots of the ascending aorta and pulmonary trunk

59. LUNGS Lobar and Segmental Anatomy

60. Right Lung

62. Left Lung

64. Bronchopulmonary Segmental Anatomy

65. These segments are the basic functional units of the lung Each pyramid-shaped segment is Enveloped by a connective tissue sheath Supplied by a single segmental bronchus and a single pulmonary arterial branch Oriented so that its apex projects toward the hilum of the lung Bronchopulmonary Segments of the Lungs

67. Right Lung Bronchogram

68. Left Lung Bronchogram

69. Surface projections of the lungs and the pleural cavities The apex of each lung projects above the medial third of the clavicle. Interlobar fissures The oblique fissure begins posteriorly in the upper thoracic region, crosses the 5th and 6th ribs, curves laterally to the midaxillary line, and courses along the lower border of the 6 th rib to the lateral border of the sternum. The right lung's horizontal fissure courses along the lower border of the 4th rib from the midaxillary line to the lateral border of the sternum

70. At midinspiration in quiet breathing, the lower margin of each lung lies at the level: The sixth rib anteriorly at the midclavicular line The eighth rib laterally at the midaxillary line The tenth rib posteriorly at the lateral border of the vertebral column Margins

71. The surface projection of the costodiaphragmatic margin of each pleural cavity passes through: The eighth rib anteriorly at the midclavicular line The tenth rib laterally at the midaxillary line The eleventh or twelfth rib posteriorly at the lateral border of the vertebral column Costodiaphragmatic Margin

72. Diaphragm The chief muscle of inspiration Accounts for 2/3 of the lungs' volumetric increase during inspiration Most effective respiratory muscle when a person is supine

73. Diaphragm higher R level of post arc of 10th rib 5th anterior rib or interspace on deep inspiration ribs below not clearly seen – opaque abdominal contents

75. Costophrenic Angle

76. Thin serous membrane Visceral pleura is NOT often definitely outlined in the normal subject Pleura

77. THE CHEST IN INFANCY AND CHILDHOOD

78. THE CHEST IN INFANCY AND CHILDHOOD AP diameter greater than transverse diameter Diaphragm is higher Ribs horizontal in infancy then angulate downwards with growth

79. THE CHEST IN INFANCY AND CHILDHOOD Sternum not completely ossified at birth- ossifies in segmental manner Two ossification centers in each segment Significance: Appear as small, rounded opacities, maybe mistaken for lesions

80. THE CHEST IN INFANCY AND CHILDHOOD thymus gland produce widening of the mediastinum Heart in NB is globular and large relative to the chest

81. THE CHEST IN INFANCY AND CHILDHOOD Lungs of infant and child more radiolucent Hilar shadow high at level of T3 Tracheal bifurcation reaches T5 at 10 yo Diaphragm higher, left maybe higher

82. Chest In Advancing age

83. Chest In Advancing age Increase dorsal kyphotic curve Increase AP diameter of chest Osteopenia Calcifications in costal cartilages Aorta becomes elongated, dilated and tortuous

84. Chest In Advancing age Emphysematous changes in lungs Apical scarring Senile emphysema Lower domes, less acute costophrenic angles

86. Review

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