Pleura

Question 1

What is pleura?

Answer 1

A serous sac formed by a thin membrane of fibrous tissue surfaced by a single layer of flat cells (mesothelium) which covers the lungs and lines the thoracic cavity.

Question 2

What are the parts of the pleura?

Answer 2

Visceral pleura
Parietal pleura

Question 3

What are the characteristics of the visceral pleura?

Answer 3

Covers the surface of the lung including horizontal and oblique fissures
Provides a smooth, slippery surface
Not sensitive to pain

Question 4

What are the characteristics of the parietal pleura?

Answer 4

Layer lining the thoracic wall (rib cage, diaphragm, vertebrae)
Attached to the inferior surface of the suprapleural membrane at the thoracic inlet and mediastinal surface of the fibrous pericardium
Sensitive to pain
Continuous with the visceral pleura at the root of the lung

Parietal pleura is separated from endothoracic fascia by loose areolar tissue

Question 5

What is the pleural cavity?

Answer 5

Space between the visceral and parietal pleurae containing serous pleural fluid allowing pleural layers to slide over each other

Question 6

What are the parts of the parietal pleura?

Answer 6

Cervical/cupola/cervical dome of pleura
Costal pleura
Mediastinal pleura
Diaphragmatic pleura

Question 7

What is the cervical pleura?

Answer 7

Part of parietal pleura which bulges through the inlet of the thorax and into the root of the neck covering the apex of each lung
Reinforced by a specialization of scalene fascia (suprapleural fascia)

Question 8

What is the costal pleura?

Answer 8

Pleura lining the inner surface of the ribs, costal cartilages and intercostal spaces
Separated from the thoracic wall by the endothoracic fascia

Question 9

What is the diaphragmatic pleura?

Answer 9

Pleura lining the superior surface of the diaphragm

Question 10

What is the mediastinal pleura?

Answer 10

Pleura lining the lateral surface of the mediastinum

Mediastinal pleura specifically covering the pericardium is called pericardial pleura

Question 11

What is the pulmonary ligament?

Answer 11

Pleura forming a 2-layered fold from the lung root to the diaphragm

Question 12

What is the purpose of the pulmonary ligament?

Answer 12

Provides a dead space into which the pulmonary veins can expand during increased venous exercise

Question 13

What are the pleural recesses?

Answer 13

Two extensions of the pleural cavity which act as reserve spaces for the lung to expand during deep inspiration

Question 14

Name the two pleural recesses

Answer 14

Costodiaphragmatic recesses
Costomediastinal recesses

Question 15

What are the costodiaphragmatic recesses?

Answer 15

Slit-like spaces between the costal and diaphragmatic pleura which are separated by a capillary layer of pleural fluid
Lies inferiorly between the costal and diaphragmatic pleura
Posteriorly it is deep, laterally and anteriorly it is shallow

Question 16

What are the costomediastinal recesses?

Answer 16

Slit-like sacs separating the costal and mediastinal parietal pleura which are separated by a thin layer of pleural fluid
Lies anteriorly behind the sternum and costal cartilages
Left is larger due to cardiac notch of left lung

Question 17

Nerves supplying the pleurae

Answer 17

Parietal pleura - Sensitive to pain, pressure, temperature and touch
* Costal pleura - intercostal nerve
* Mediastinal pleura - phrenic nerve
* Diaphragmatic pleura - phrenic nerve and lower 6 intercostal nerves

Visceral pleura - Only sensitive to stretch
* Autonomic nerves from the pulmonary plexus

Question 18

What is the blood supply of the pleurae?

Answer 18

Parietal pleura supplied by branches of the internal thoracic, superior phrenic and intercostal arteries (its pia)
Visceral pleura supply with blood from the bronchial arteries

Question 19

What are the surface markings of the cervical pleura?

Answer 19

Convex upward from the sternoclavicular joint to a point 2.5cm above the junction of the medial and intermediate thirds of the clavicle and bulges up into the neck

Question 20

What are the surface markings of the anterior border of the right pleura?

Answer 20

Runs downward behind the sternoclavicular joint & continues downward until it reaches the xiphisternal joint (6th costal cartilage)

Question 21

What are the surface markings of the anterior border of the left pleura?

Answer 21

At the 4th costal cartilage it deviates laterally & extends to the lateral margin of the sternum to form the cardiac notch
Then it turns sharply downward to the xiphisternal joint

Question 22

What are the surface markers of the lower border of the pleura?

Answer 22

Extends from the level of 6th costal cartilage (xiphisternal junction) around the chest wall
Then it crosses on both sides it follows a curved line, which crosses the 8th rib in the midclavicular line and the 10th rib to the midaxillary line, and reaches the 12th rib adjacent to thoracic vertebra

Question 22

What are the surface markers of the lower border of the pleura?

Answer 22

Extends from the level of 6th costal cartilage (xiphisternal junction) around the chest wall
Then it crosses on both sides it follows a curved line, which crosses the 8th rib in the midclavicular line and the 10th rib to the midaxillary line, and reaches the 12th rib adjacent to thoracic vertebra