BRONCHOPULMONARY SEGMENTS OF THE LUNG

A pre requisite for any medical resident to know. the different bronchopulmonary segments and their clinical importance in quite a detail.

1. BRONCHOPULMONARY SEGMENTS Dr. Surabhi Sushma Reddy Postgraduate Dept of pulmonary medicine

2. INDEX History Nomenclature Anatomical significance Clinical significance Radiological significance Etiological significance Surgical significance

3. ANATOMICAL CHARACTRISTICS OF LOBES

4. THE RIGHT LUNG : 1.Right upper lobe : Has large anterior projection three segments Is smaller than the left upper lobe 2.Middle lobe Only has anterior projection two segments Is wedge-shaped in outline 3.Right lower lobe Lies inferior and posterior to the oblique major fissure five segments Inferior surface lies over the diaphragmatic dome (diaphragmatic surface)

5. THE LEFT LUNG : 1. Left upper lobe Is much bigger than the right upper lobe Has large anterior projection Supplies four segments Has a wide cardiac notch anteriorly Has lingula, which is a small tongue like projection located antero-inferiorly 2. Left lower lobe Is larger than the upper lobe Lies inferior and posterior to the oblique major fissure Supplies four segments

6. SURFACE ANATOMY Fissures :often seen in chest x-ray. Best demonstrated on BUCKY films.1.Horizontal fissure. 2.Oblique fissure Surface marking of parietal pleura(8 th ,10 th ,12 th ribs) 1.cervical pleura 2.anterior margin 3.inferior margin 4.posterior margin Surface marking of the lungs(6 th ,8 th ,10 th ribs) 1.apex of the lung 2.anterior border 3.inferior border 4.posterior border

7. SURFACE ANATOMY Major interlobar fissure is marked by a line drawn from T2 spine along the medial border of the scapula, with the arm kept hyperabducted , to the 6th rib at its costochondral junction, crossing the 5th rib at the mid axillary line. It corresponds to the upper border of the lower lobe . Minor interlobar fissure is marked by a horizontal line drawn from the sternum at the level of 4th costal cartilage to meet the first line of the major interlobar fissure. It marks the boundary between the upper and middle lobes.

8. BRONCHOPULMONARY SEGMENTS

9. DEFINITION Each Segmental bronchus passes to a structurally and functionally independent unit of lung lobe called as Broncho Pulmonary Segment. These are well defined Anatomic, Functional and surgical units of lungs

10. HISTORY In 1932 krammer & Glass coined the phrase “bronchopulmonary segments” In 1939 churchill & belsey paved way to segmental resection. In 1949, 10 normal segments were given specific numbers by thoracic society. In 1960 slight modification of nomenclature by international congress of anatomist.

11. .Resistance to airflow in the traheobronceal tree depends on the total cross-sectional area of the airways .Small /peripheral airways :silent zone

12. Airway Progression Trachea : 16-20 C- shaped hyaline cartilage rings Bifurcates at the level of sternal angle . Carina : Ridge on internal aspect of last cartilage. Point where trachea branches. Left main bronchus : Longer(5 cm),smaller diameter, more horizontal, makes an angle of 45 o with trachea. Gives 2 lobar bronchi Right main bronchus : Shorter(2.5cm), larger diameter, more vertical( 45 o ), more susceptible to aspiration. Gives 3 lobar bronchi. Each main or primary bronchus runs into the hilus of lung posterior to pulmonary vessels

13. Airway Progression - Segmental Bronchus divides into Sub segmental Bronchi 16 -Sub segmental Bronchus Divides into Bronchioles . -Tubes smaller than 1 mm diameter called bronchioles -Smallest terminal bronchioles are less than 0.5 mm diameter -Bronchioles have no Cartilage.

14. Airway Progression Respiratory Bronchiols: 2 or more branches from each terminal bronchioles with air sac buds. This is first level of gas exchange. Respiratory bronchioles end in alveoli. Pores of khan & channels of Lambert are present to connect two alveoli 17

15. Characteristic Features of BPS Largest subdivision of lung lobe. Pyramidal in shape with apex towards the root of hilum. Each segment is an independent respiratory unit. Each segment has its own separate artery [branches of pulmonary artery],segmental bronchus, autonomic nerves & lymph vessels.

16. Characteristic Features of BPS The segmental vein runs in the connective tissue between adjacent BPS. Thus a broncho pulmonary segment is not a bronchovascular segment, as it does not have its own vein. Usually the infection of BPS remains restricted to it ,although tuberculosis and bronchogenic carcinoma may spread from one segment to another.

17. NOMENCLATURE OF BRONCHOPULMONARY SEGMENTS

18. RIGHT LUNG JACKSON-HUBER BOYDEN BROCK THORACIC SOCIETY (1943) (1955) OF GREAT BRITAIN UPPER LOBE APICAL B1 APICAL APICAL POSTERIOR B2 PECTORAL POSTERIOR ANTERIOR B3 SUBAPICAL ANTERIOR MIDDLE LOBE LATERAL B4 LATERAL LATERAL MEDIAL B5 MEDIAL MEDIAL LOWER LOBE SUPERIOR B6 APICAL APICAL MEDIAL BASAL B7 CARDIAC MEDIAL BASAL ANTERIOR BASAL B8 ANTERIOR BASAL ANTERIOR BASAL LATERAL BASAL B9 MIDDLE BASAL LATERAL BASAL POSTERIOR BASAL B10 POSTERIOR BASAL POSTERIOR BASAL

19. Right lung

20. JACKSON-HUBER BOYDEN BROCK THORACIC SOCIETY LEFT OF GREAT BRITAIN UPPER LOBE UPPER DIVISION APICO-POSTERIOR B1-3 APICAL AND APICO POSTERIOR SUBAPICAL OR APICAL AND ,, ANTERIOR B2 PECTORAL ANTERIOR LINGULAR DIVISION SUPERIOR B4 SUPERIOR SUPERIOR INFERIOR B5 INFERIOR INFERIOR LOWER LOBE SUPERIOR B6 APICAL APICAL ANTERO-BASAL B7-8 ANTERIOR ANTERIOR BASAL LATERAL BASAL B9 MIDDLE BASAL LATERAL BASAL POSTERO BASAL B10 POSTERIOR BASAL POSTERIOR BASAL LEFT LUNG

21. LOCATION OF BPS ON CXR

22. Right upper lobe B1 Apical segment CXR- PA : medially –mediastinum, laterally-line drawn from the hilum along ant border of 1 st rib CXR- lat :- D2 vertebral body to hilum hilum to out border of 1 st rib.

23. B 2 Posterior Segment CXR PA:line drawn from apex to hilum abutting the outer border of first rib. Another line drawn from hilum to 3 rd ICS. not silhouttes ascending aorta CXR LAT:D 2 to hilum and hilum to D4

24. B 3 Anterior Segment CXR PA: hilum out border of 2 nd rib hilum to chest wall along 4 th rib . Silhouette sign on ascending aorta . CXR-Lat :hori fissure, hilum to 1 st rib.

25. Middle Lobe B4 & B5 {Lateral & Medial } Segments CXR-PA :horizontal line hilum to chest wall, lower part of oblique fissure. Silhouettes rt heart border . CXR-Lat :hori hilum to 4 th costo Chondral jn ,lower half of oblique fissure.

26. Right lower Lobe B6 Segment CXR PA :super imposes on right hilum CXR LAT:Upwards –hilum to posterior border of D4 vertebra Downwards hilum to D7 vertebra. Not silhouetting the cardiac border.

27. B 7 medial Basal Small triangle shape post ends of 8 th to 10 th rib Silhouetting cardio phrenic angle

28. B 8 Anterior Basal Diamond shaped CXRPA: Inf- lat 2/3 of diaph Sup-lower border of 8 th rib post, Med-hilum to medial 1/3 of diaph Lat :lower part of oblique fissure ,ant to mid axillary line

29. B 9 Lateral Basal Segment CXR-PA: occupies the costo phrenic angle & Lat 2/3 of Diaphragm CXR LAT: Extends from mid axillary line from D10 to hilum

30. B 10 Posterior Basal CXR PA: occupies a Para cardiac rectangle Space, not silhouetting the cardiac border CXR Lat: D7 to hilum Hilum to diaph D7 to D10

31. Apico posterior Segment(BI,B3 ) PA :hilum to 2 nd rib. Obliterates the aortic knob. Lat :upper part of oblique fissure , hilum to 2 nd costal

32. B 2 Anterior Segment PA : hilum to 2 nd rib hilum to 4 th rib Not silhouettes aortic knob. Lat : hilum to 2 nd coastal, hilum to 4 th coastal cartilage

33. B 4 & B5 Lingular Segments PA :hilum to 4 th rib, lower part of oblique fissure. Lat :lower part of oblique fissure ,hilum to 4 th coastal cartilage . . silhouettes the lt cardiac border

34. Lingular seg

35. Left Lower Lobe B6 Superior Segment CXR PA : Oval shape 6 th rib and 8 th rib, no silhouette sign , CXR Lat :upper part of oblique fissure , D4 to D7, hilum to D7.

36. B 7 & B 8 Anterio-medial Segment Lat; lower part of oblique fissure Mid axillary line PA : upper margin extending from hilum to lower border of 8 the rib. Lower border obliterates lateral 1/3 of diagram and extending up to mid axilla

37. B 9 Lateral Basal Segment Lat wedge shape ant and post to mid axillary line

38. B 10 Posterior Basal Segment PA: Rectangle Para cardiac, no silhouette sign, lat: hilum to D7 hilum to diaphragm.

39. LOCATION OF BPS ON CT SCAN Most commonly used levels 1.At the level of aortic arch 2.At the level of Lt pulmonary artery level. 3.At the level of Rt pulmonary artery level. 4.At the level of cardiac ventricles

40. At The Level of aortic arch level purely upper lobe BPS At aortic arch level

41. Lt pul.art. level

42. Rt pul.art.level

43. At the level of cardiac ventricles

44. BRONCOSCOPIC VIEW VIEWVIEWopticBronchoscopy 61

45. CLINICAL IMPORTANCE

46. Double lesion sign : Collapse of multiple lobes or segments in certain combinations almost rules out malignancy (RUL+RML ,LLL+LUL, RML+ one segment of RLL ) Exceptions : - multi centric neoplasm - primary & metastasis - extension thru fissure - tumor +inflammation

47. SILHOUTTE SIGN FELSON & Felson in 1950 Silhoutte sign : is applied to localize parenchymal lesions which can be stated as “an intrathoracic lesion with similar radiologic density is in contiguity with either heart, aorta, or diaphragm will obliterate the border, as the radiographic contrast is lost.” - Right cardiac border –Rt middle lobe - Lt cardiac border - Lingula - Aortic knuckle –Apico post.LUL - Rt .aortic border -Ant.RUL ; middle lobe - Hemi diaphragm -Basal seg of LL from medial to lateral Anterior basal, medial basal &lateral basal -

48. 1.Tuberculosis —apical & post segments of upper lobes.because of high ventilation perfusion ratios with elevated alveolar PO2 relative to other zone 2.Sequestration of lung -posterior basal segment of lower lobe (left>>right) 3.Cancerous lesion -anterior segments of RUL. 4.Lung abscess —posterior segment of the upper lobe or in the superior or posterior basal segment of the lower lobe, especially on the rt lung because of more vertical bronchus and also that aspirated secretions tend to gravitate in these segments in supine position

49. 5.Aspiration pneumonia : apical segments both lower lobes or posterior segment of the RUL . Bronchiectasis more common in left lower lobe because of longer and narrower bronchus leading to retained secretions.

50. MICROBIOLOGICAL SIGNIFICANCE TB STAPH STREP H.Infl Adeno Infl Mycoplasma Strep,chlamydia Anaerobic Histoplasma Atypical inf virus

51. SURGICAL IMPORTANCE

52. SUGICAL RESECTION *PNEUMONECTOMY *LOBECTOMY *SEGMENTECTOMY *WEDGE RESECTION- Peripheral lesions Lung apex Lung base Adjacent fissure

53. s Segmentectomy

54. PRINCIPLE: A diseased segment,as it is a structural unit can be removed surgically. During surgical resection, the surgeon works along the segmental veins to isolate a particular segment. * Indications : Aspergilloma TB Bronchiectasis Metastatic disease Primary lung cancer

55. Contra indications: Extrinsic segmental compression Presence of endoluminal tumor Prerequisites: complete bronchoscopy Advantages : 1)thorough resection 2)better staging 3)decreasing local recurrence

56. Each lung contribution to total FEV 1 is assumed to be proportionate to the % of total pulmonary blood flow as detected by radio isotope technique – Xenon 133/ technetium A predicted post operative FEV1 of at least 800ml should be required before pneumonectomy. Predicted postoperative FEV1 =% of blood flow to remaining lung x pre operative FEV1 Each lobe of lung contributes to one fifth of total FEV 1

57. For lobectomy, regional quantitative perfusion scans may be used. Alternatively, the postoperative FEV1 may be predicted using the following equation: Predicted post operative FEV1 = Preoperative FEV1 × (number of lung- segments remaining after resection divided by total number of segments in both lungs)

58. Pulmonary Hygiene Postural Drainage & Percussion Frequently Known As “ Pulmonary Toilet ”

59. Postural Drainage & Percussion Postural Drainage : Positioning the patient so that retained secretions in the broncho pulmonary tree can drain by gravity out of the lungs. Percussion : A rhythmic percussion on the thoracic wall to loosen secretions and assist the mucociliary escalator to get rid of the retained secretions

60. Research has shown that a 30-45 minute PD & P session can clear the lung fields of secretions. An x-ray of the lungs pre and post treatment demonstrates a dramatically improved lung.

61. Positioning The Patient Positioning the patient is important to allow the bronchi of each bronco pulmonary segment to be vertical so that the fluid inside the bronchus will move toward the main stem bronchi and out of the lung.

62. The Apical segments of Both Upper Lobes PD: High long sitting. . Angle 30-45 degree backward on reclined sitting. Per & Aus: Over the trepezius between the clavicle anteriorly & scapula posteriorly

63. The Anterior Segments of Both Upper Lobes PD: 1 . Drained with patient supine. 2.The bed remains flat. 3.Pillows under the knees & head. Per & Aus : Over the pectoralis muscle.

64. The Posterior Segment of LUL PD : 1.The thorax elevated approximately 30 degrees . 2.Raising the head of bed or by placing the whole bed 30 degrees up from horizontal . 3.Pt positioned one-quarter turn from prone onto right side with left shoulder pillowed. Per & Aus : over the scapula

65. The Posterior Segments of RUL PD: 1 . The Pt positioned one-quarter turn from prone onto left side. 2. right shoulder pillowed. 3.The bed remains flat. Per&Aus :over the scapula

66. The RML & LINGULA PD : 1.Pt lies head down on and rotates ¼ turn backward. 2.On left side for RML,ON RIGHT side for lingula. 3.A 12 inch( about 15 degrees )bed elevation is recommended. 4.A pillow may be placed behind the pt from shoulder to hip. Per & Aus: over the nipple extending in to the mid –axillary line.

67. The Superior segments of Both Lower Lobes PD: 1.Prone flat. 2.Pillows under the hips & knees 3. none under the head Per & Aus :over the thorax at the inferior angle of scapula.

68. The Lateral Basal Segment of RLL PD: 1.Pt lying on left side. 2.Elevate foot end of the table 18 inches(30 degrees) 3.The Pt can flex upper leg over a pillow for support . Per&Aus :over the thorax wall in the mid axillary line at the inferior border of the thorax

69. The Lateral Basal Segment of LLL & The Medial Basal Segment of RLL PD: 1.Pt lying on Right side. 2.Elevate foot end of the table 18 inches(30) 3.The Pt can flex upper leg over a pillow for support . Per&Aus: over the thorax wall on the left lateral surface in the mid axillary line.

70. The Posterior Basal Segments of Both Lower Lobes PD: 1.Pron, head down position, with pillow under the head. 2.Elevate foot end of table 18 inches(30). Per&Au s:over the posterior thorax just above the inferior borders of the thorax cage .

71. The Anterior Basal Segments of Both Lower Lobes. PD: 1.Supine with head down and a pillow behind the neck & the knees 2.elevate foot end 18 inches (30 degrees) Per&Aus : over the thoracic wall on the anterior surface just above the inferior border of thoracic cage.

72. SEGMENTAL & SUBSEGMENTAL VARIATIONS

73. RUL 1.Bifurcation 2.Four segments: extra one usually from double origin of the post.bronchus,one of which supplies the lateral (axillary )segment. 3.Anomalous bronchus: -Arises from the Rt side of the trachea above the RUL bronchus . -Usually it is displaced branch of apical segment. Rarely a true supernumerary bronchus. RML 1.Small lateral and large medial segments. 2.Arrangement like lingula.

74. RLL * In most cases the superior segment sits transversely on the basal segments. In few cases obliquely. 1.Sub Superior segment; between the superior & the basal segments. 2.lateral segment may be absent. LUL Bifurcation in 75% cases 1.In remainders, a trifurcation occurs: a. Modified superior division , b.lingul , c.anterior division. 2.a tracheal bronchus. LLL -In most cases superior segment rests obliquely on the basal segments. 1.Rarely superior segment bronchus arises at the bifurcation of the main stem bronchus. 2.Sub Superior segment.

75. AZYGOS LOBE 1% of anatomic specimens 0.4% of CXR Superomedial portion of UL Comma shaped end on shadow positioned in the crotch b/w UL bronchus & trachea. As it has no bronchi, veins & arteries of its own it is not a true or even accessory pulmonary lobe. .But it is rather an anatomically separate part of the upper lobe Left side azygos lobe is a rare anomaly .

76. AZYGOS LOBE FISSURE FOR AZYGOS VEIN RIGHT LUNG

77. SUP. ACC. LOBE: 5% of anatomic specimens MC on right side Superior segment of lower lobe separated by an incisura or a complete septum Mistaken for minor fissure on CXR-PA Appears as a post. Continuation of minor fissure

78. INFERIOR ACCESSORY LOBE Seen in 1/3 of anatomic dissections Part of major fissure.

79. FOUR LOBES

80. TWO LOBES

81. FOETAL LUNG WITH 4 LOBES

82. BIBILIOGRAPHY INDERBIR SINGH’S EMBRYOLOGY ATLAS OF NETTER’S ANATOMY GRAY’S ANATOMY DUTTA TEXTBOOK OF HISTOLOGY McGregor's SURGICAL ANATOMY ROBINS TEXT BOOK OF PATHOLOGY PANIKERS TEXT BOOK OF MICROBIOLOGY POTTER & PERRY FUNDAMENTALS OF NURSING FISHMANS PULMONARY DISEASES & DISORDERS CHEST ROENTGENOLOGY BY FELSON

83. THANK YOU