Lungs, Pleura Lecture Notes PDF

Anatomy – MED 201  Basics ❖Definition: A body cavity containing major parts of cardiovascular and respiratory system ❖Functions ❖Protects heart, lungs and major vessels ❖Breathing ❖Conduit for esophagus ❖Communication with neck, abdomen ❖Contents ❖Pleural c...

Anatomy – MED 201  Basics ❖Definition: A body cavity containing major parts of cardiovascular and respiratory system ❖Functions ❖Protects heart, lungs and major vessels ❖Breathing ❖Conduit for esophagus ❖Communication with neck, abdomen ❖Contents ❖Pleural cavities (Lungs) ❖Mediastinum (Heart, esophagus)  Thoracic inlet Communication with neck, arms Contents Trachea 1st rib T1 Esophagus Great vessels Sternum 1st rib  Thoracic outlet Communication with abdomen Inferior ribs T10-12 Contents Esophagus Great vessels Thoracic wall  General overview Shape of thoracic cavity ✓ Osteocartilagenous conical cage ✓ Inlet– narrow ✓ Outlet– wide  General overview 2 pleural cavities, one mediastinal  Lungs ❖Separated by mediastinum ❖Right lung larger than left ❖ each lung – enclosed by double layer pleural membrane ❖ Parietal pleura – lines wall of thoracic cavity ❖ Visceral pleura – covers lungs  Lungs ❖ Cone shaped ❖ Apex ❖ Base ❖ 3 borders ❖ Inferior ❖ Anterior ❖ Posterior ❖ 2 surfaces ❖ Costal ❖ Mediastinum  Lungs Apex Hilum Base  Lungs Apex ❖ Extends 1-2 cm past clavicles ❖ Projects into root o Base ❖ Sits on diaphragm ❖ Right ❖ Right lobe of liver ❖ Left ❖ Left lobe of liver ❖ Stomach ❖ Spleen f neck  Lung surfaces ❖ Costal Surface ❖ Mediastinal Surface  Lung surfaces Costal surface ❖ Immediately adjacent to ribs ❖ In contact with thoracic wall ❖ Smooth, few distinctive markings costal pleura  Lung surfaces Mediastinal surface ❖ Lies adjacent to mediastinum ❖ Contains hilum ❖ Imprints of various anatomic elements in contact  Lung Borders Inferior border ❖ Sharp ❖ Separates the base from the costal surface Anterior border ❖ Separates costal surface from medial surface ❖ Sharp Posterior border ❖ Separates costal surface from medial surface ❖ Smooth & rounded  Lung Roots ❖ Short tubular collection of structures ❖ In mediastinum ❖ Covered by mediastinal pleura ❖ Pleura reflects onto surface of lung (visceral pleura) ❖ Region outline = hilum  Lung Hilum ❖ Opening on medial surface of lungs ❖ Contains ❖ Main bronchus ❖ 2 pulmonary veins ❖ 1 pulmonary artery ❖ Lymphatics ❖ Nerves  Lung fissures & lobes Right Lung ❖ 2 fissures ❖ Oblique ❖ Horizontal ❖ 3 lobes ❖ Upper ❖ Middle ❖ Lower Left Lung ❖ 1 Fissure ❖ Oblique ❖ 2 lobes ❖ Upper ❖ Lower Lingula Lung hilums Lung surfaces Right lung Lung surfaces Left lung Bronchial tree  Lobar bronchi ❖ Main bronchus divides in lung to give off 2ndary (lobar) bronchi (lobes) ❖ Divide further into segmental bronchi (bronchopulmonary segments) ❖ Segmental bronchi give off multiple generations – to bronchioles  Bronchopulmonary segments Segment ❖ area of lung having a separate bronchus & pulmonary a. ❖ Smallest, functionally independent region that can be 10 resected ❖ segments / lung ❖ Pulmonary vein tributaries pass between segmentally ❖ Each segment shaped like irregular cone with apex at origin of bronchus & base on surface  circulation Pulmonary Pulmonary Pulmonary artery vein Venous Arterial circulation (Superior & Inferior vascularization circulation (Aorta) Somatic vena cava) Capillary bed  Lung vascularization Each lung has ❖ 1 Pulmonary artery (deoxygenated blood) ❖ 2 pulmonary veins (oxygenated blood)  Lymphatic drainage Superficial lymphatic plexus Deep lymphatic plexus  Superficial lymphatic drainage ❖ Subpleural plexus ❖Lies deep to visceral pleura ❖ Drains ❖Lung parenchyma (tissue) ❖ Visceral pleura ❖ Lymphatic vessels drain into bronchopulmonary lymph nodes in hilum (hilar lymph nodes)  Deep lymphatic drainage ❖ Lies in submucosa of bronchi & in peribronchial tissue ❖ Drains ❖ Structures of root of lung ❖ Lymphatic vessels drain into ❖ Intrinsic pulmonary lymph nodes (along lobar bronchi)  Lymphatic drainage Lymph from lobes of lungs drains into pulmonary & bronchopulmonary (hilar) nodes Then tracheobronchial (carinal) nodes Paratracheal nodes Right lymphatic duct (right lung) Thoracic duct (left lung) Innervation of the lung ❖ Pulmonary plexus follows trachea & bronchial tree ❖Anterior pulmonary plexus (Anterior to root of lung) ❖Posterior pulmonary plexus (Posterior to root of lung)  Lungs innervation Parasympathetic X Pulmonary plexus T1 Sympathetic T2 T3 Cervical g. T4 Sympathetic trunk. Lungs surface anatomy  Right lung Horizontal fissure ❖ ~ T4 spinous process ❖ 5th intercostal space (midclavicular ln) ❖ follows 4th intercostal space  Right lung Oblique fissure ❖ ~ T4 spinous process ❖ 5th intercostal space (midclavicular ln) ❖ follows contour of rib VI rib 6  Left lung Oblique fissure ❖ ~T3 - T4 spinous process ❖ 5th intercostal space, ❖ follows contour of rib VI Lung auscultation Orientation of fissures determines where to listen for lung sounds from each lobe Stethoscope is positioned on thoracic wall related to underlying position of lobe  Right lung auscultation Where to listen for lung sounds: Upper lobe Middle lobe Lower lobe  Left lung auscultation Where to listen for lung sounds: Upper lobe Lower lobe  Pleura (pleural membranes) [on the surface of the ❖ Serous membranes Visceral Pleura lung itself] ❖ Line internal surface of rib thoracic cage (parietal pleura) & outside surface of lungs (visceral pleura) Parietal ❖ Pleurae secret fluid – Pleura decreases resistance against lung movement during breathing  the potential space situated between Pleural space = parietal & visceral pleura Outer layer (Parietal pleura) Each pleural space contains a minimal Pleural Space amount of pleural fluid Inner layer (Viscerall pleura)  Pleura Each pleural sac is composed of 2 layers of serous (secretory) membrane (=pleura) Parietal pleura ❖ external serous membrane ❖ Lines internal surface (wall) of thoracic cavity Visceral pleura ❖ Internal serous membrane ❖ Intimately attached to lung surface  Pleura Visceral pleura Parietal pleura  Visceral pleura ❖Completely covers the lung ❖enters fissures to cover lobes ❖ smooth surface & freely ❖ is continuous with parietal mobile pleura at the root  Parietal pleura Mediastinal parietal pleura ❖ Lines lateral surface of mediastinum Costal parietal pleura ❖ Lines inner surface of ribs Diaphragmatic parietal pleura ❖ Lines superior surface of diaphragm Cervical parietal pleura (cupula) ❖ Extends above rib 1 to root of neck Pleural reflection  Pleural recesses ❖ Lungs do not completely fill the anterior or posterior inferior regions of the cavities → recesses ❖ Expansion of lungs into these spaces occurs only during forced inspiration ❖ spaces also provide potential space for fluid build up  Pleural recesses Costomediastinal recess ❖ Anterior ❖ Occurs on each side ❖ Where costal pleura is opposed to mediastinal pleura ❖ Largest is on the left side over heart  Pleural recesses Costodiaphragmatic recess ❖ Inferior ❖ Occurs on each side ❖ Where costal pleura is opposed to diaphragmatic pleura ❖ Largest is on the left side over heart  Pleura vascularization Parietal pleura ❖ internal thoracic ❖ superior phrenic ❖ Posterior intercostal ❖ Superior intercostal arteries Bronchial arteries ❖ Bronchial arteries  Pleura innervation Intercostal nerves ❖ Costal parietal pleura ❖ Peripheral portion of diaphragmatic parietal pleura Phrenic nerves ❖ Central portion of diaphragmatic parietal pleura ❖ Mediastinal parietal pleura General sensory neurons Sensitive to Pain ! Pleura fluid accumulation Questions?