PLEURAL CAVITY DR ROBERTON GAUTAM - PowerPoint Presentation

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PLEURAL CAVITY

DR ROBERTON GAUTAM

SR, JNMC, ALIGARH

Pleural cavity

The thoracic cavity is divided into three compartments

:

right and left lateral compartments and middle compartment. Each lateral compartment is occupied by a lung enclosed in the serous sac called pleural cavity. The mass of tissues and organs occupying the middle compartment form a mobile septum—mediastinum that completely separates the two pleural cavities.

PLEURAL CAVITIES

Each

lung is invested by and enclosed in a serous sac

which consists of two continuous serous membranes—the visceral pleura and parietal pleura.The visceral pleura invests all the surfaces of the lung forming its shiny outer surface, whereas the parietal pleura lines the pulmonary cavity (i.e., thoracic wall and mediastinum).The space between the visceral and parietal pleura is called pleural cavity.

The

pleural

cavity is normally filled with a thin film of

tissue fluid

, which lubricates the adjoining surfaces of the

pleura and

allows them to move on each other without friction.

The two layers become continuous with each other

by means

of a

cuff of pleura, which surrounds the root of

the

lung

consisting of structures entering and leaving the lung

at the

hilum

of the lung, such as principal bronchi

and

pulmonary vessels

.

PLEURA

The

pleura-like peritoneum is a serous membrane lined

by flattened epithelium (mesothelium). The lining epithelium secretes a watery lubricant—the serous fluid.LAYERS OF THE PLEURAThe pleura consist of two layers: (a) visceral pleura and (b) parietal pleura. The moistened space between the two layers is called pleural cavity (vide supra).Parietal pleura, according to the surface, which it lines, covers or the region in which it

lies,

is

divided into

the following four parts

:

1. Costal pleura.

2. Diaphragmatic pleura.

3.

Mediastinal

pleura.

4. Cervical pleura.

Pulmonary ligament

It is the Pleura around the root of lung extends down as a fold.

Extends down till diaphragm.

Contains : loose areolar tissue and lymphatics Functions:

Dead space into which pulmonary veins can expand.

Allows descent of root of lung with descent of diaphragm during inspiration

.

Lines of pleural reflection.

RECESSES OF THE PLEURA

in

areas of pleural reflection on to

the diaphragm and mediastinum, the space between the parietal and visceral pleura is greatly expanded and are called pleural recesses. They are essential for lung expansion during deep inspiration. The recesses of pleura are as follows: 1. Costodiaphragmatic

recesses (right and left).

2

.

Costomediastinal

recesses (right and left).

three

more small

recesses

Right

and left

retroesophageal

recesses

Infracardiac

recess

Costodiaphragmatic

recess

: It is located inferiorly between the costal and diaphragmatic pleurae. Vertically it measures about 5 cm and lies opposite the 8th–10th ribs along the

midaxillary lineCostomediastinal recess : It is located anteriorly between the costal and mediastinal pleurae and lies between sternum and costal cartilages. The left costomediastinal recess is large due to the presence of cardiac notch in the left lung.

Radiological appearance of pleural effusion

the

costodiaphragmatic

angle is obliterated (widening of the angle). It is seen as radiopaque shadow with a fluid line in X-ray chest. Sites of extension of pleura beyond the thoracic cage:There are five sites, where pleura extends beyond the thoracic cage : 1. On either side in the root of the neck (as domes of pleura). 2

. In the right

xiphisternal

angle.

3

. On either side in the

costovertebral

angle.

The pleura can be punctured inadvertently at these

sites during

surgical procedures.

NERVE SUPPLY OF THE PLEURA

The

parietal pleura

is supplied by the somatic nerves and is sensitive to pain.Costal and peripheral part of the diaphragmatic pleura is supplied by the intercostal nerves. Mediastinal and central part of the diaphragmatic pleura is supplied by the phrenic nerve.The visceral pleura

is

supplied by

the autonomic

(sympathetic) nerves (T2–T5) and is

insensitive to

pain

.

Referred pain of pleura

: The pain from

central

diaphragmatic

pleura and

mediastinal

pleura is referred

to the

neck or shoulder through

phrenic

nerves (C3, C4,

and C5)

Differences between the parietal and visceral pleurae

Parietal pleura

Lines

the thoracic wall and mediastinumDevelops from the somatopleuric mesodermInnervated by the somatic nervesSensitive to painBlood supply and lymphatic drainage is same as that of thoracic

wall

Visceral

pleura

Lines the surface of the lung

Develops from the

splanchnopleuric

mesoderm

Innervated by the autonomic nerves

Insensitive to pain

Blood supply and lymphatic drainage is same as that of the lung

BLOOD SUPPLY AND LYMPHATIC DRAINAGE OF THE PLEURA

Blood

supply of parietal pleura is same as that of

the thoracic wall and blood supply of the visceral (pulmonary) pleura is same as that of the lung.

CLINICAL

Pleurisy or

pleuritis

: It is the inflammation of the parietal pleura. Clinically it presents as pain.The collection of serous fluid, air, blood, and pus in the pleural cavity is termed hydrothorax (pleural effusion) pneumothorax, hemothorax, and pyothorax (empyema), respectively.Pleural effusion: Normally the pleural cavity contains

only 5–10 ml of clear fluid, which lubricates

the pleural

surfaces to allow their smooth movements

without friction.

Thoracocentesis

/pleural tab: It is a procedure by

which

an excess fluid is aspirated from the pleural cavity. It is performed with the patient in sitting position. Usually the needle is inserted in the 6th intercostal space in the midaxillary line.

Pneumothorax

:

Accumulation of air in the pleural cavity is called pneumothorax.- Spontaneous pneumothoraxOpen pneumothoraxTension pneumothorax