PLEURA BY ATIBA, P

PLEURABY

ATIBA, P.M

GROSS ANATOMY OF THORAX

ANA 202

05/04/2020 Gross Anatomy of Pleura and Lungs 2

The pleura is refer to as the serous membranes that lines the lungs and thoracic cavity.

Each pleural cavity is lined by a single layer of flat cells, mesothelium, and an associated layer of supporting connective tissue; together, they form the pleura.

INTRODUCTION

Elsevier. Drake et al: Gray’s Anatomy for students www.studentconsult.com

http://www.studentsconsult.com/

INTRODUCTION

The pleura is divided into two major types, based on location:

parietal pleura;

visceral pleura




STRUCTURES OF PLEURAEparietal pleura is the pleura associated with the walls of a pleural cavity

visceral pleura is the pleura that reflects from the medial wall and onto the surface of the lung which adheres to and covers the lung.




PLEURA CAVITY

Each pleural cavity is the potential space enclosed between the visceral and parietal pleurae.




PARIETAL PLEURAIt is subdivided by the part of the thoracic cavity they in contact with:

pleura related to the ribs and intercostal spaces is termed the costal part;

pleura covering the diaphragm is the diaphragmatic part;




PARIETAL PLEURApleura covering the mediastinum is the mediastinal part;

the dome-shaped layer of parietal pleura lining the cervical extension of the pleural cavity is cervical pleura(dome of pleura or pleural cupola).




Peripheral reflections

The extent of the pleural cavities are marked by peripheral reflections of the pleura parietal.





Superiorly, the pleural cavity can project as much as 3-4 cm above the first costal cartilage, but does not extend above the neck of rib I.




Peripheral reflections Anteriorly, the pleural cavities approach each other posterior to the upper part of the sternum.

Posterior to the lower part of the sternum, the parietal pleura does not come as close to the midline on the left side




Peripheral reflections Inferiorly, the costal pleura reflects onto the diaphragm above the costal margin. In the midclavicularline, the pleural cavity extends inferiorly to approximately rib VIII.





In the midaxillaryline, it extends to rib X. From this point, the inferior margin courses somewhat horizontally, crossing ribs XI and XII to reach vertebra TXII.




Peripheral reflections From the midclavicular line to the vertebral column, the inferior boundary of the pleura can be approximated by a line that runs between the rib VIII, rib X, and vertebra TXII.




Visceral pleura

Visceral pleura is continuous with parietal pleura at the hilum of each lung where structures enter and leave the organ.




Visceral pleura

The visceral pleura is firmly attached to the surface of the lung, including both opposed surfaces of the fissures that divide the lungs into lobes.




Pleural recesses The lungs do not completely fill the anterior or posterior inferior regions of the pleural cavities. This results in recesses in which two layers of parietal pleura become opposed.




Pleural recesses Expansion of the lungs into these spaces usually occurs only during forced inspiration; the recesses also provide potential spaces in which fluids can collect and from which fluids can be aspirated.




CostomediastinalrecessesAnteriorly, a costomediastinalrecess occurs on each side where costal pleura is opposed to mediastinal pleura. The largest is on the left side in the region overlying the heart.




Costodiaphragmatic recesses

The largest and clinically most important recesses are the costodiaphragmaticrecesses, which occur in each pleural cavity between the costal pleura and diaphragmatic pleura




Costodiaphragmatic recesses

The costodiaphragmaticrecesses are the regions between the inferior margin of the lungs and inferior margin of the pleural cavities. They are deepest after forced expiration and shallowest after forced inspiration.




Neurovascular Supply

The two parts of the pleurae receive a different neurovascular supply.

Parietal Pleura: Innervation by phrenic and intercostal nerves




Neurovascular Supply

The blood supply is by the intercostal arteries.

Visceral Pleura: Innervation is by pulmonary plexus.

The blood supply is through the bronchial arteries.




GROSS ANATOMY OF LUNGSBY

ATIBA, P.M

GROSS ANATOMY OF THORAX

ANA 202

INTRODUCTIONThe lungs are the essential organs of respiration.

Each lung is attached by its root and pulmonary ligament to the heart and trachea but is otherwise free in the thoracic cavity.


Moore et al., 2010: Clinical Oriented Anatomy

INTRODUCTIONThe lungs are light, soft, spongy, and elastic, and, because they contain air, they float in water.

The surface of an adult lung is usually mottled, and it presents dark gray or bluish patches caused by inhalation of atmospheric dust.



INTRODUCTION

The main bronchus enters the hilus and subdivides within the substance of the lung to form the "bronchial tree.“

The right lung, is heavier, shorter and wider than the left lung.



Surfaces and borders

Each lung has an apex, three surfaces (costal, medial, and diaphragmatic), and three borders (anterior, inferior, and posterior).



Surfaces and bordersThe right lung is divided into upper, middle, and lower lobes by oblique and horizontal fissures, whereas the left lung has usually only upper and lower lobes, separated by an oblique fissure.



Surfaces and bordersThe bronchi and pulmonary vessels, which extend from the trachea and heart, respectively, collectively form the root of the lung. The part of the medial surface where these structures enter the lung is known as the hilus.05/04/2020 Gross Anatomy of Pleura and Lungs 29



The apex is rounded and fills the cupola of the pleura. The costal surface, which is related to the sternum, costal cartilages, and ribs, joins the medial surface at the anterior and posterior borders and the diaphragmatic surface at the inferior border.



Surfaces and bordersThe medial surface is related posteriorly to the sides of the bodies of the vertebrae. Anteriorly, the medial surface is related to the superior, middle, and posterior parts of the mediastinum and includes the hilus.



Surfaces and bordersThe diaphragmatic surface, or base, rests on the dome of the diaphragm, which separates the lung from the liver (on the right side) or the stomach, spleen, and sometimes liver and left colic flexure (on the left side).




The azygos vein, instead of arching over the hilus of the right lung, arches over the upper lobe so that it isolates a medial part of the lung, called the lobule of the azygos vein.



Surfaces and bordersThe anterior border of the lung corresponds to that of the pleura, although it is uncertain whether the costomediastinalrecess of the pleura is completely filled by the lung during quiet breathing, as it is in deep inspiration.




The anterior border of the left lung probably deviates more to the left (cardiac notch) than does that of the pleura.




The inferior border of the lung occupies the costodiaphragmatic recess of the pleura, although it is too thin to be demonstrated by percussion during quiet breathing.




The inferior limit of the lung that can be outlined by percussion extends laterally from the xiphisternal joint and about two intercostal spaces higher than the pleura. It crosses rib 6 in the midclavicular line and rib 8 in the midaxillary line and then proceeds toward the 10th thorac vertebra.



Lobes and fissures

The right lung is divided into upper, middle, and lower lobes by an oblique and a horizontal fissure. The left lung is divided into upper and lower lobes by an oblique fissure.



Lobes and fissures

The oblique fissure follows approximately the line of rib 6 as far as the inferior border of the lung.



Lobes and fissures

When the arm is abducted and the hand placed on the back of the head, the medial border of the scapula indicates approximately the oblique fissure.


Lobes and fissuresThe horizontal fissure begins at the oblique fissure near the midaxillary line (of the right side), at about the level of rib 6. It extends forward to the anterior border at the level of costal cartilage 4. It may be incomplete or even absent.



Root

The root of the lung consists of the structures entering and emerging at the hilus. It connects the medial surface of each lung to the heart and trachea.



Root

It is surrounded by pleura, which is prolonged below as the pulmonary ligament. The roots of the lungs descend on deep inspiration.



Root

The chief structures in the root are the bronchi and pulmonary vessels. Also included are nerves, bronchial vessels, and lymphatics and nodes.



RootThe heart and great

vessels are anterior to the trachea and main bronchi, and this relationship is maintained in the root of the lung, where the anterior-posterior order, is veins, artery, and bronchus, with the artery superior to the veins.


Bronchopulmonary segmentsThe main bronchus divides into lobar (second-order) bronchi, each of which then divides into segmental (third-order) bronchi. The portion of lung supplied by a third-order bronchus is known as a bronchopulmonarysegment.



Bronchopulmonary segmentsA given segment may be located by radiography or bronchoscopy. Pulmonary disorders may be localized in a bronchopulmonarysegment, and surgical removal of a segment is feasible. The segments are separated from each other by connective tissue septa.



Bronchopulmonary segmentsAlthough variations are not uncommon, the bronchopulmonarysegments have been named and numbered There are slight differences between the right and left lungs: briefly, in the left lung, segments 1 and 2 are generally combined, and commonly segments 7 and 8 are also.



Bronchopulmonary segmentsThe branches of the pulmonary artery accompany the bronchi but are more variable. Pulmonary veins do not accompany the bronchi, but run between the segments; hence they are guides to intersegmental planes.



Blood supply, lymphatic drainage and innervation

Blood to be oxygenated is carried by the pulmonary arteries, whereas the tissue of the bronchial tree and alveoli is nourished by the bronchial arteries. The branches of the pulmonary arteries within the lungs accompany the bronchi and end in capillary networks in the alveoli.




The arteries at the hilusare visible radiographically and form a pattern that extends into the lung. The pulmonary veins collect oxygenated blood from the lung and deoxygenated blood from the bronchi and visceral pleura.




Pulmonary veins are intersegmentalin location. Usually four pulmonary veins enter the left atrium.




Bronchial arteries, usually one on the right and two on the left, arise commonly from the aorta, but variations are frequent. They supply oxygenated blood to the non-respiratory tissues of the lungs, including the visceral pleura.




Bronchial veins carry deoxygenated blood from the first few bronchial divisions to the azygos system.




Carbon particles in the superficial lymphatics give the lung a grayish and mottled appearance. Superficial and deep lymphatic vessels drain toward the hilus and end in pulmonary and bronchopulmonary nodes. These in turn drain into the tracheobronchial nodes.




The anterior and posterior pulmonary plexuses around the root of the lung are formed by branches of the vagiand sympathetic trunks. Parasympathetic fibers(of vagal origin) supply the smooth muscle and glands of the bronchial tree.




Spasm of the bronchial musculature occurs in asthma and can be relieved by epinephrine. Sympathetic fiberssupply blood vessels and probably relax bronchial smooth muscle.




Afferent fibers(vagal) from the visceral pleura and bronchi are concerned with the reflex control of respiration. Irritation of endings in the bronchial mucosa provokes coughing.



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PLEURA BY ATIBA, P

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