Pleura Flashcards
what 2 layers is the pleura made up of
-outer parietal layer
-inner visceral layer
what is the parietal pleura divided into
- Costal pleura
- Diaphragmatic pleura
- Mediastinal pleura
- Cervical pleura
what does the costal pleura line
Lines the inner surface of the thoracic wall, but separated from it by endothoracic fascia
what does the Diaphragmatic pleura cover
Covers the superior surface of the diaphragm
what does the Mediastinal pleura line
Lines the corresponding surface of the mediastinum and forms its lateral boundary. Over the root of the lung it becomes continuous with the visceral pleura
how does the cervical pleura extend
It is the dome of parietal pleura which extends into the root of the neck. It is called cupola and covers the apex of the lung, hence care should be taken while penetrating this area with anesthetic needle. It is covered by suprapleural membrane or Sibson’s fascia.
what is the pulmonary ligament formed by
After surrounding the root of the lung the pleura extends down as a fold called pulmonary ligament
what is the pulmonary ligament filled with
loose areolar tissue and contain few lymphatics
what is the function of the pulmonary ligament
It provides dead space for the expansion of inferior pulmonary vein during high venous return as in exercise
It allows the descent of the root of the lung with the descent of the diaphragm during inspiration
what is the surface marking of the cervical pleura
Marked by a curved line (convexity directed upwards) drawn from sternoclavicular joint to the junction of medial third and middle third of the clavicle. The summit of the dome of pleura lies 1 inch above the medial one-third of the clavicle.
what is the surface marking of the Anterior (costomediastinal) line of pleural reflection
On the right side-
It extends downwards and medially from the right sternoclavicular joint to the midpoint of the sternal angle, then descends vertically up to the midpoint of the xiphisternal joint
On the left side-
It extends downwards and medially from the left sternoclavicular joint to the midpoint of the sternal angle, then descends vertically only up to the level of the 4th costal cartilage.
what is the surface marking of the inferior (costomediastinal) line of pleural reflection
On the right side-
The line of pleural reflection starts from the xiphisternal joint or behind the xiphoid process and crosses the 8th rib in the midclavicular line, 10th rib in the midaxillary line and 12th rib at the lateral border of the erector spinae muscle, 2cm lateral to the spine of T12
On the left side-
The line of pleural reflection starts at the level of the 6th costal cartilage, about 2cm lateral to the midline. Thereafter it follows the same course as on the right side
where is the Costomediastinal recess
Lies anteriorly behind the sternum and costal cartilages, between the costal and mediastinal pleura
Prominent in the cardiac notch of the lung
where is the Costo-diaphragmatic recess
Lies inferiorly between the costal and diaphragmatic pleurae. The line of this reflection is two ribs lower than the lower border of the lung. So this recess is not filled by lung during quiet inspiration and is partially filled by lung during deep inspiration.
what is the development of the parietal pleura
develops from somatopleuric layer of lateral plate mesoderm
what is the nerve supply of the parietal pleura
Supplied by somatic nerves – intercostal and phrenic nerve
Costal and peripheral part of diaphragmatic pleura are supplied by intercostal and phrenic nerves
Mediastinal and central part of diaphragmatic pleurae are supplied by phrenic nerve
what is the arterial supply of the parietal pleura
by branches from the intercostal, internal thoracic and musculophrenic arteries
where do the veins of the parietal pleura drain
into azygos and internal thoracic veins
what is the lympathic drainage of the parietal pleura
Lymphatics drain into intercostal, internal mammary, posterior mediastinal and diaphragmatic nodes
how does the pulmonary pleura develop
from splanchnopleuric layer of lateral plate mesoderm
what is the nerve supply of the pulmonary pleura
Supplied by autonomic (sympathetic) nerves (T2-T5), which accompany the bronchial vessels
what is the blood supply of the pulmonary pleura
bronchial vessels
what is the lymphatic drainage of the pulmonary pleura
Lymphatics drain into bronchopulmonary lymph nodes
what is the importance of the pleural cavity
-The opposed surfaces of parietal and visceral pleura are lined by mesothelial cells.
They secrete a small quantity of serous fluid into the space continuously which is essential for the movement of the lungs (to prevent rubbing during lung movements).
-A negative pressure is maintained inside the pleural cavity which is necessary to retain visceral pleura in contact with parietal pleura.
If there is positive pressure (i.e., pneumothorax) inside the pleural cavity, the inherent elastic recoil of the lung tissue pulls the visceral pleura away from the parietal pleura causing the collapse of the lung.
