Pleura and Lung

By Prof. Saeed Abuel Makarem & Dr. Sanaa Al Sharawi

Objectives Objectives

By the end of the lecture, the student should be able to :

• Describe the anatomy of the pleura: (subdivisions into parietal & visceral pleurae, nerve supply).

• List the parts of parietal pleura and its recesses.• Describe the surface anatomy of both pleurae and

lungs.• Describe the anatomy of lungs : (shape, surfaces,

relations, nerve supply, blood supply and lymphatic drainage.

• Describe the difference between right & left lungs.• Describe the formation of bronchopulmonary

segments and its main characteristics.

SUFACE ANATOMY OF PLEURA• Apex:

• lies one inch above the medial 1/3 of the clavicle.

• Left pleura:

• The anterior margin extends from sternoclavicular joint to the level of 4th costal cartilage, then deviates for about 1 inch to left at 6th costal cartilage to form cardiac notch.

• Right pleura:

• The anterior margin extends vertically from sternoclavicular joint to 6th costal cartilage.

• Inferior margin : passes round chest wall, on the 8th rib in midclavicular line, 10th rib in mid-axillary line and finally reaching to the last thoracic spine.

• Posterior margin : along the vertebral column from the apex to the inferior margin.

SURFACE ANATOMY OF LUNG• Apex, anterior border

and posterior border correspond nearly to the lines of pleura but are slightly away from the median plane.

• Inferior margin:

• as the pleura but more horizontal and finally reaching to the 10th thoracic spine.

• Oblique fissure:

• represented by a line extending from 3rd thoracic spine, obliquely ending at 6th costal cartilage.

• Transverse fissure only in right lung: represented by a line extending from 4th right costal cartilage to meet the oblique fissure.

PLEURA

• It is a closed serous sac which surrounds the lung and invaginated from its medial side by the root of lung.

• It has 2 – layers: parietal pleura which which lines the thoracic lines the thoracic cavity. cavity. & visceral pleura which which surrounds surrounds the lung,the lung, separated by a pleural cavity.

• Pleural cavity:• Contains 5-10 ml. of

serous fluid which lubricates both sufaces and allows the lungs to move free during respiration.

Divisions of parietal pleura Divisions of parietal pleura • 1- Cervical pleura:1- Cervical pleura:

It is part of It is part of parietal pleura which parietal pleura which protrudes up into the protrudes up into the root of the neck.root of the neck.

• 2-Costal pleura:2-Costal pleura: It lines inner It lines inner surface of ribs, costal surface of ribs, costal cartilages, intercostal cartilages, intercostal muscles and back of muscles and back of the sternum.the sternum.

• 3-Diaphragmatic 3-Diaphragmatic pleura:pleura: It covers upper It covers upper surface of the surface of the diaphragm.diaphragm.

• 4-Mediastinal pleura:4-Mediastinal pleura:

It covers mediastinal It covers mediastinal surface of the lung.surface of the lung.

Visceral PleuraVisceral Pleura firmly covers outer firmly covers outer

surfaces of the lung surfaces of the lung and extends into its and extends into its fissures.fissures.

The 2- layers The 2- layers ((mediastinalmediastinal parietal parietal pleura pleura & visceral & visceral pleura)pleura) are continuous are continuous with each other to with each other to form form a tubular sheath a tubular sheath (pleural cuff)(pleural cuff) that that surrounding root of surrounding root of lung (vessels, nerves & lung (vessels, nerves & bronchi) in the hilum bronchi) in the hilum of the lung.of the lung.

On the lower surface of On the lower surface of root of the lung, root of the lung, pleural cuff hangs pleural cuff hangs down asdown as a fold called a fold called pulmonary ligament.pulmonary ligament.

Pleural Pleural Recesses Recesses

Costodiaphragmatic recess : lies between costal & diaphragmatic parietal pleura along the inferior border.

Costomediastinal recess : lies between costal & mediastinal parietal pleura along the anterior border..

The lung reaches these recesses only in deep inspiration.

Pleural Effusion Pleural Effusion • It is an abnormal accumulation of pleural fluid about 300 ml, in the Costodiaphragmatic Costodiaphragmatic recess , (normally 5-10 ml of clear fluid)

• Causes: • Inflammation, TB,

malignancy, congestive heart disease.

• The lung is compressed & the bronchi are narrowed.

• Auscultation would reveal only faint & decreased breath sounds over the compressed or collapsed lung.

• Dullness on percussion over the effusion.

Nerve Supply of Pleura Nerve Supply of Pleura

• Parietal pleuraParietal pleura….…. • Costal P.PCostal P.P….….by by

intercostal nerves.intercostal nerves.

• Mediastinal P.PMediastinal P.P….….by by phrenic nerve.phrenic nerve.

• Diaphragmatic P.PDiaphragmatic P.P.:.: 1-Medially1-Medially by by phrenic nerve.phrenic nerve. 2-2-Peripheral partPeripheral part.. by .. by lower 6 intercostallower 6 intercostal nerves.nerves.

• Visceral pleuraVisceral pleura…… sympathetic N.S.sympathetic N.S. from from pulmonarypulmonary plexus.plexus.

Blood supply of PleuraBlood supply of Pleura

• Parietal pleuraParietal pleura…… by by intercostal, internal intercostal, internal thoracic & thoracic & musculophrenic musculophrenic vessels.vessels.

• Visceral pleuraVisceral pleura …. ….by by bronchial vessles.bronchial vessles.

Lymphatic Drainage:Lymphatic Drainage:• Parietal pleura :Parietal pleura : into into

intercostalintercostal,,,, mediastinalmediastinal & & diaphragmaticdiaphragmatic Lymph Nodes.Lymph Nodes.

• Visceral pleura :Visceral pleura : into into broncho-pulmonary broncho-pulmonary Lymph Nodes in the Lymph Nodes in the hilum of the lung.hilum of the lung.

LUNGSLUNGS• Each lung has

the following features:

• It is conical in shape.

• It has an apex, a base and 2 surfaces.

• The costal surface of each lung borders the ribs (front and back).

• On the medial (mediastinal) surface, the bronchi, blood vessels, and lymphatic vessels enter the lung at the hilum.

LUNGSLUNGS• Apex:Apex: projects projects

into into root of the root of the neckneck (one inch (one inch above the medial above the medial 1/3 of the 1/3 of the clavicle). clavicle). It is coveredIt is covered by by cervical pleura.cervical pleura.

It is groovedIt is grooved anteriorlyanteriorly by by subclavian artery.subclavian artery.

• Base: (inferior= Base: (inferior= diaphragmatic diaphragmatic surface)surface) is is concaveconcave and sits on the and sits on the diaphragm.diaphragm.

BordersBorders: Anterior & Posterior : Anterior & Posterior

• Anterior border : is sharp, thin and overlaps the heart.

• Anterior border of left lung presents a cardiac notch at its lower end + thin projection called the lingula below the cardiac notch.

• Posterior border : is rounded, thick and lies beside the vertebral column.

Surfaces: Costal & Mediastinal Surfaces: Costal & Mediastinal • Costal surface:• Convex.• Covered by costal pleura

which separates lung from: ribs, costal cartilages & intercostal muscles.

• Medial surface: • It is divided into 2 parts:• Anterior (mediastinal) part:• Contains a hilum in the

middle (it is a depression in which bronchi, vessels, & nerves forming the root of lung).

• Posterior (vertebral) part:• It is related to: bodies of

thoracic vertebrae, intervertebral discs, posterior intercostal vessels & sympathetic trunk.

Lateral & medial surfaces of right lung

RIGHT RIGHT LUNG LUNG ROOTROOT

• 2 bronchi 2 bronchi lie lie posterior. posterior.

• Pulmonary Pulmonary arteryartery is is superiorsuperior

• 2 Pulmonary 2 Pulmonary veinsveins are are inferior and inferior and anterior.anterior.

LEFT LEFT LUNG LUNG ROOTROOT

• One One bronchusbronchus lies lies posteriorposterior

• Pulmonary Pulmonary arteryartery is is superior superior

• 2 Pulmonary 2 Pulmonary veinsveins are are inferior and inferior and anterior.anterior.

Right Right lung lung

• Larger & shorter than left lung.

• Divided by 2 fissures (oblique & horizontal) into 3 lobes (upper, middle and lower lobes).

LeftLeft LungLung

• Divided by one oblique fissure into -2 lobes, Upper and lower.

• There is No horizontal fissure.

• It has a cardiac notch at lower part of its anterior border.

Mediastinal surface of right lung Mediastinal surface of right lung • On the mediastinal On the mediastinal

surface of the right surface of the right lung,lung, you find these you find these structures: structures:

• Azygos vein Azygos vein and and its its arch arch (posterior and (posterior and over the root of the over the root of the lung).lung).

• Vagus nerve Vagus nerve posterior posterior to the root. to the root.

• Esophagus above and Esophagus above and posterior to the root. posterior to the root.

• Phrenic nerve Phrenic nerve anterior anterior to the root.to the root.

• Cardiac impression:Cardiac impression: related to right atrium. related to right atrium.

• Below hilum and in front of pulmonary ligament:

• Groove for I.V.C.

Cardiac impression

Mediastinal surface of left lung Mediastinal surface of left lung • On the mediastinal On the mediastinal

surface of the left surface of the left lung,lung, you will find you will find these structures:these structures:

• Descending aorta Descending aorta posterior to the root.posterior to the root.

• Vagus nerve Vagus nerve posterior posterior to the root.to the root.

• Arch of the aorta Arch of the aorta over over the root. the root.

• Groove for left Groove for left common carotid common carotid artery. artery.

• Groove for left Groove for left subclavian artery. subclavian artery.

• Phrenic nerve Phrenic nerve anterior anterior to the root.to the root.

• Cardiac impression :Cardiac impression : related to left related to left ventricle. ventricle.

Cardiac impression

Blood supply of lungBlood supply of lung

• Bronchial arteriesBronchial arteries (branches of descending (branches of descending thoracic aorta)thoracic aorta)….. ….. supply oxygenated blood supply oxygenated blood to to bronchi , lung tissue & visceral pleura.bronchi , lung tissue & visceral pleura.

• Bronchial veins :Bronchial veins : drain into azygos & drain into azygos & hemiazygoshemiazygos veins.veins.

• Pulmonary arteryPulmonary artery which carries which carries non-oxygenated bloodnon-oxygenated blood from from right ventricleright ventricle to to the the lung alveoli.lung alveoli.

• 2 pulmonary veins :2 pulmonary veins : carry carry oxygenated bloodoxygenated blood from from lung alveolilung alveoli to the to the left atrium.left atrium.

Nerve Supply of the lung Nerve Supply of the lung

• Pulmonary plexusPulmonary plexus : :• at the root of lung….is formed of at the root of lung….is formed of autonomic autonomic

N.S.N.S. from sympathetic & parasympathetic from sympathetic & parasympathetic fibres.fibres.

1- Sympathetic F.1- Sympathetic F. from .. from ..sympathetic trunksympathetic trunk broncho-dilatation broncho-dilatation /and vasoconstriction./and vasoconstriction.

2- Parasympathetic F.2- Parasympathetic F. from…. from….Vagus nerveVagus nerve …. …. Broncho-constrictionBroncho-constriction and and secretomotorsecretomotor to to bronchial glands /and vasodilatation.bronchial glands /and vasodilatation.

Lymph drainage of the lungsLymph drainage of the lungs • There are 2 lymphatic

plexuses…. superficial & deep plexuses.

• Superficial plexus (subpleural): lies under the visceral pleura and drain to bronchopulmonary nodes in the hilum of lung.

• Deep plexus:• Lies along the bronchial tree &

pulmonary blood vessels and drain into the pulmonary nodes within the lung substance.

• Then into bronchopulmonary nodes in the hilum of lung.

• Then into the tracheo-bronchial nodes at the bifurcation of trachea , and finally into broncho-mediastinal lymph trunks to end in thoracic duct (left) or in right lymphatic duct (right).

BronchiBronchi

• The trachea divides The trachea divides into 2 main bronchi:into 2 main bronchi:

• Right main bronchus:Right main bronchus: It It divides before divides before entering the hilumentering the hilum, it , it gives off gives off superior superior lobar (secondary) lobar (secondary) bronchus.bronchus. On entering hilum,On entering hilum, it it divides into divides into middle middle & & inferiorinferior lobar bronchi. lobar bronchi.

• Left main bronchusLeft main bronchus:: On entering hilumOn entering hilum, it , it divides intodivides into superiorsuperior & & inferiorinferior lobar lobar bronchi.bronchi.

• Within the lung each bronchus divides into number of branches that can be divided into two groups:

I- Conduction zone I- Conduction zone branchesbranchesPrimary (main) bronchiSecondary (lobar) bronchiTertiary (segmental) bronchi (supply the bronchopulmonary segment)Smaller bronchi BronchiolesTerminal bronchioles

II- Respiratory zone II- Respiratory zone branchesbranches

• Respiratory bronchioles

• Alveolar ducts

• Alveolar sacs

• Alveoli

Bronchial Divisions

Bronchopulmonary segments Bronchopulmonary segments • They are the

anatomic, functional, and surgical units of the lungs.

• Each lobar (secondary) bronchus gives off segmental (tertiary) bronchi.

• Each segmental bronchus divides repeatedly into bronchioles.

• Bronchioles divide into terminal bronchioles, which show delicate outpouchings ‘the respiratory bronchioles’.

Bronchopulmonary segments Bronchopulmonary segments

• The respiratory bronchioles end by branching into alveolar ducts, which lead into alveolar sacs.

• The alveolar sacs consist of several alveoli, each alveolus is surrounded by a network of blood capillaries for gas exchange.

Characteristics of Bronchopulmonary segments Characteristics of Bronchopulmonary segments • It is a subdivision of a

lung lobe. • It is pyramidal in

shaped, its apex lies toward the root, while its base lies on the lung surface.

• It is surrounded by connective tissue septa.

• It has a segmental bronchus, a segmental artery, lymph vessels, and autonomic nerves.

• The segmental vein lies in the inter- segmental C.T. septa between the segments.

• A diseased segment can be removed surgically, because it is a structural unit.