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 10th thoracic spine.

Oblique fissure: Represented by a line

extending from 3rd thoracic spine, obliquely ending at 6th costal cartilage.

Transverse fissure: Only in the right lung: represented by a line extending from 4th 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 lungA. 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 lung Left 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 lungsIt gives passage to the It gives passage to the

structures forming the structures forming the Root of the lung.

1. Bronchus2. Pulmonary artery3. Pulmonary veins4. 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 RIGHT LUNG LUNG ROOTROOT

2 bronchi: Lie posterior. Pulmonary

artery: Is superior Pulmonary

veins: Are inferior

and anterior.

LEFT LEFT LUNG LUNG ROOTROOT

One bronchus:

Lies posterior

Pulmonary artery:

Is superior

Pulmonary veins:

Is inferior and anterioranterior

Difference between the right and left lungs

Right Lung Left Lung

Size and weight Larger and heavier Smaller and lighter

Length and breadth

Shorter and wider Longer and narrower

LobesFissures

Three Two

Two One

Anterior border No cardiac notch Cardiac notch and lingula.

Bronchial Tree

Bronchopulmonary Segments

Bronchopulmonary 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 artery2) the superior bronchial artery on the left side3) any number of the right intercostal arteries mostly the third right posterior.

Nerve supplyPulmonary 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.

Thank You