Thoracic Cavity Flashcards
What are the components of the thoracic cavity?
- Lungs
- Trachea
- Heart
- Oesophagus
- Great vessels
- Azygos system
- Thoracic duct
- Sympathetic trunk
- Thymus gland
- Bronchi
- Pleural membranes
What nerves are found in the thoracic cavity?
- Vagus and phrenic
- Sympathetic chain and splanchnic nerves
What are the components of the serous pericardium?
- Parietal layer
- Visceral layer
Describe the vagus nerve and what are its two branches?
- Runs down with the carotid artery
- Right and left recurrent laryngeal nerve
Describe the passage of the L recurrent laryngeal nerve
- Loops under arch of aorta
Describe the passage of the R recurrent laryngeal nerve
- Under right subclavian vein
- More posterior to phrenic nerve
Where do the pleural membranes join?
- Root of the lung
Which pleura is thicker?
- Parietal
What happens to the pleural membranes at the base of the lung?
- Part to form costodiaphragmatic recesses for lung expansion
- T12 at the back up to T6 in the front follow fissures of the lung
What are the 5 layers of the visceral pleura?
1) Mesothelial layer- serous fluid
2) CT layer
3) Superficial layer (elastic)- stretch
4) Loose subpleural CT layer (vessels, nerves)
5) Deep fibre-elastic layer
Which pleural membrane is sensitive to pain, touch, temp and pressure?
- Parietal pleura
What nerve supplies the costal pleura?
- Ribs
- Intercostal nerve
What nerve supplies the mediastinal part of the parietal pleura?
- Heart
- Phrenic nerve
What nerve supplies the diaphragmatic pleura?
- Diaphragm
- Phrenic
- Lower 6 intercostal nerves
What is the visceral pleura sensitive to?
- Stretch but not pain and touch
What is the nervous supply of the visceral pleura?
- Pulmonary plexus
- PNS and SNS only
What is the blood supply of the parietal pleura?
- Intercostal, internal thoracic and musculophrenic
What is the blood supply of the visceral pleura?
- Bronchial vessels
Describe the lymphatic drainage of the parietal pleura
- Intercostal, mediastinal, diaphragmatic lymph nodes
Describe the lymphatic drainage of the visceral pleura
- Bronchopulmonary lymph nodes in the hilum of the lung
What does the pleural membrane connect and why?
- Connection between the rib cage and the lung tissue
- As both layers are connected to each other
What are the two recesses of the lung and what is their function?
- Costodiaphragmatic
- Mediastinal
- Allow expansion of the lung
What is pleural effusion?
- Fluid build-up in the pleural cavity
- Meniscus (upright)
- Decubitus (meniscus on the side)
What is a pneumothorax?
- Air in the pleural cavity
- Collapsed lung due to elastin
- Uncoupling of lung from chest wall
- Likely to be one-sided- comprises saturation, less ventilation
What type of pneumothorax might occur during trauma?
- Tension pneumothorax
- Penetrating injury
- Wound acts as a valve
- Increased air in pleural cavity
- This can cause tracheal deviation towards the normal lung
What are the signs of pneumothorax?
- Chest pain
- Shortness of breath
- Increased heart rate
- Cyanosis
How can a tension pneumothorax result in cardiac arrest?
- Mediastinum shifted towards normal lung
- Obstructs venous return
- Circulatory instability
- Cardiac arrest, therefore quick treatment
What is thoracentesis?
Fluid taken from pleural space- diagnostic/therapeutic
What structures do you have to go through to reach the parietal pleura in thoracentesis?
- Skin, subcutaneous fat, internal and external intercostal muscles, innermost intercostal muscles, fascia, parietal pleua
- Draw fluid
What is a chest drain?
- Removal of fluid from a cavity
- Triangle of safety
- 5th intercostal space as there are no major vessels or nerves
Where is the mediastinum found?
At the sternal angle
What are the contents of the superior mediastinum?
- Arch of aorta, pulmonary trunk, oesophagus, trachea, recurrent laryngeal nerve
What are the contents of the anterior inferior mediastinum?
- Thymus
- Internal thoracic arteries and veins
- Lymphatics and lymph nodes
What are the contents of the middle inferior mediastinum?
- Heart and pericardium
- Ascending aorta
- Pulmonary trunk
- Sup and inf vena cava
- R+L pulmonary veins, arteries, phrenic nerves
- Lymph nodes
What are the contents of the posterior inferior mediastinum?
- Oesophagus
- Thoracic duct
- Sympathetic trunk
- Azygos system
- Vagus nerves
- Primary bronchi
What are the boundaries of the thoracic inlet?
- Posteriorly- first thoracic vertebra (T1)
- Laterally- first pair of ribs
- Forms lateral C-shaped curves posterior to anterior
- Anteriorly- costal cartilage of 1st rib and superior border of manubrium
What structures pass through the midline of the thoracic inlet?
- Trachea
- Oesophagus
- Recurrent laryngeal nerves
- Thoracic duct
What structures pass through posteriorly through the thoracic inlet from medial to lateral?
- Sympathetic trunk
- Supreme intercostal vein
- Superior intercostal artery
