Lungs Dr. Sama ul Haque Dr Rania Gabr

Objectives  Define mediastinum.  Discuss the anatomical structure of lungs.  Enlist the relations of right and left lungs.  Give the blood and nerve supply of the lungs.

Mediastinum Definition: A median septum or median partition between the two pleural cavities.

Superior boundary: Superior thoracic aperture Inferior boundary: Diaphragm Anterior boundary: Sternum Posterior boundary: Bodies of vertebrae T1 to T12 Lateral boundaries: Mediastinal parietal pleura (left and right). Boundaries of the Mediastinum

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 horizontally and finally reaching to the 10 th thoracic spine. Oblique fissure:  Represented by a line extending from 3 rd thoracic spine, obliquely ending at 6 th costal cartilage. Transverse fissure: Only in the right lung: represented by a line extending from 4 th right costal cartilage to meet the oblique fissure.

Gross Anatomy of the Lungs  Each lung has a conical shape, concave base rests upon the muscular diaphragm.  Its superior region is called Apex.  Toward the midline, the lungs are separated from each other by the Mediastinum.  The relatively broad, rounded surface in contact with the thoracic wall is called the Costal surface of the lung.

Lungs Left lung  divided into 2 lobes by oblique fissure  smaller than the right lung.  Cardiac Notch accommodates the heart Right Lung  divided into 3 lobes by oblique and horizontal fissure

Lungs  An apex  A base  3 borders:  Anterior  Posterior  Inferior  2 surfaces: Medial and costal. Medial surface: Mediastinal & vertebral

Apex And Base of the lung Apex: It extends up 1 inch above and behind the medial third of the clavicle. Base: It is concave in shape. It is related to: 1- Diaphragmatic pleura. 2- Right copula of the diaphragm. 3- Liver (right lung). Liver, stomach (fundus), and spleen (left lung).

Borders of the lung A. Anterior border It is a sharp border. The lower part of the anterior border of the left lung contains the cardiac notch (just below the cardiac notch there is a projection called the lingula). B. Posterior border It is a rounded border. C. Inferior border

Lobes &Fissures of the lungs Three lobes:  Superior  Middle  Inferior Fissures:  Oblique fissure  Transverse fissure Two lobes  Superior  Inferior Fissure:  Oblique fissure Right lungLeft lung

Lobes and fissures of Lungs

Mediastinal Surface of the Right Lung  Cardiac impression (Right atrium).  Superior vena cava.  Inferior vena cava.  Right subclavian artery.  Right brachiocephalic vein  Azygos vein.  Esophagus.  Trachea.  Thymus

Mediastinal Surface of the Left Lung  Cardiac impression (Left ventricle).  Arch of Aorta.  Descending aorta.  Left subclavian artery.  Left brachiocephalic vein  Thoracic duct.  Esophagus.  Trachea.  Thymus

Hilum of the lungs It gives passage to the structures forming the It gives passage to the structures forming the Root of the lung. 1. Bronchus 2. Pulmonary artery 3. Pulmonary veins 4. Hilar lymph nodes. 5. Bronchial vessels. 6. Pulmonary plexuses 7. Pulmonary ligament The parietal pleura surrounding the root of the lung extends downwards from the hilum in a fold called the pulmonary ligament Hilum of left lung Hilum of right lung

RIGHT LUNG ROOT RIGHT LUNG ROOT  2 bronchi:  Lie posterior.  Pulmonary artery:  Is superior  Pulmonary veins:  Are inferior and anterior.

LEFT LUNG ROOT  One bronchus:  Lies posterior  Pulmonary artery:  Is superior  Pulmonary veins: anterior  Is inferior and anterior

Difference between the right and left lungs Right LungLeft Lung Size and weightLarger and heavierSmaller and lighter Length and breadth Shorter and widerLonger and narrower Lobes Fissures Three Two One Anterior borderNo cardiac notchCardiac notch and lingula.

Bronchial Tree

Bronchopulmon ary Segments

Respiratory Bronchioles, Alveolar Ducts, and Alveoli  Lungs contain small sacs called alveoli.  They have a thin wall specialized to promote diffusion of gases between the alveolus and the blood in the pulmonary capillaries.

Respiratory Bronchioles, Alveolar Ducts, and Alveoli  Gas exchange can take place in the respiratory bronchioles and alveolar ducts as well as in the alveoli, each lung contains approximately 300 to 400 million alveoli.  The spongy nature of the lung is due to the packing of millions of alveoli together.

Respiratory Bronchioles Alveolar Ducts And Alveoli

Blood supply of Lungs  Pulmonary circulation:  Bronchial circulation: Bronchial arteries supply oxygenated blood to lungs, bronchial veins carry away deoxygenated blood from lung tissue.

Pulmonary Circulation

The left bronchial arteries (superior & inferior) usually arise directly from the Thoracic aorta. The single right bronchial artery usually arises from one of the following: 1) the Thoracic aorta at a common trunk with the right 3rd Posterior intercostal artery 2) the superior bronchial artery on the left side 3) any number of the right intercostal arteries mostly the third right posterior.

Nerve supply  Pulmonary plexus at the root of lung….is formed of 1- Sympathetic Fibers From … sympathetic trunk… Action: broncho-dilatation/and vasoconstriction. 2- Parasympathetic Fibers From…..Vagus nerve …. Action: Broncho-constriction and secretomotor to bronchial glands /and vasodilatation.

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