Pleural Cavities & Mediastinum Flashcards
pleural cavities
- potential space between the layers of pleura
- contains capillary layer of serous pleural fluid
pericardial cavity
- potential space between opposing layers of parietal and visceral layers of serous pericardium
- normally contains thin film of fluid that enables the heart to move and beat in a frictionless environment
thoracic inlet
- superior thoracic aperture
thoracic outlet
- inferior thoracic aperture
parietal pericardium
- internal surface of fibrous pericardium lined with glistening serous membrane
visceral pericardium
- reflection of parietal pericardium onto heart at great vessels (aorta, pulmonary trunk and veins, and superior/inferior vena cavae)
mediastinum
- central compartment of thoracic cavity
- occupied by mass of tissue between the two pulmonary cavities
- contains all thoracic viscera and structures except lungs
pleural recesses
- where two layers of parietal pleura touch each other
- costodiaphragmatic recess = where parietal costal and parietal diaphragmatic pleura meet
- costomediastinal recess = where parietal costal and parietal mediastinal pleura meet
pleural sac
- consists of two membranes: parietal and visceral
What are the boundaries of the inferior mediastinum? What structures fall in this portion?
- between transverse thoracic plane and diaphragm
- further divided into anterior, middle, and posterior parts
What are the boundaries of the anterior mediastinum? What structures fall in this portion?
- anterior border is sternum, lateral borders are mediastinal pleura, posterior border is pericardium
What are the boundaries of the middle mediastinum? What structures fall in this portion?
- anterior border is anterior margin of pericardium, posterior border is posterior border of fibrous pericardium, lateral borders are mediastinal pleura
- pericardium and its contents (heart and roots of its great vessels)
What are the boundaries of the posterior mediastinum? What structures fall in this portion?
- posterior border is bodies of thoracic vertebrae, anterior border is posterior border of fibrous pericardium, lateral borders are mediastinal pleura
pleural tap (thoracocentesis)
- insertion of hypodermic needle through an intercostal space (9th space in midaxillary line during expiration) into pleural cavity to obtain sample of fluid or remove blood/pus
- needle inserted superior to rib, high enough to avoid collateral branches of nerves/blood vessels
- needle passes through intercostal muscles and costal parietal pleura into pleural cavity
Innervation of the pleura?
- Vagus nerve (CN X) ends up in lungs and heart
- visceral pleura have afferents traveling back with parasympathetic
- parietal pleura have afferents that feed back into somatic system
- phrenic nerve supplies diaphragm –> runs through mediastinum
air/fluid/blood/tumor in pleural cavity
- accumulation of air in pleural cavity –> pneumothorax
- accumulation of fluid in pleural cavity –> hydrothorax
- accumulation of blood in pleural cavity –> hemothorax
pericardial tap (pericardiocentesis)
- drainage of fluid from pericardial cavity to relieve cardiac tamponade (compression of heart caused by fluid collecting in pericardium)
How would a cervical injury with a knife affect the pleura?
- would cause a hemothorax?
