Anatomy of lower respiratory tract Flashcards
What is the pleura composed of?
Double membrane
What are the 2 layers of the pleura?
Parietal: lines interior thoracic walls and covers mediastinum
Visceral: Is inseparable from the lung over all surfaces including those in the fissures
What is the pleural cavity?
The fluid filled cavity between visceral and parietal pleura
How much fluid is there in the pleural cavity?
~15ml
What does pleural fluid do?
They lubricate the friction from damaging lining during visceral and parietal pleura
What is the condition in which there is liquid that leaks into the pleural cavity?
Pleural effusion
What are the 4 parts of the parietal pleura?
Cervical pleura (covered by layer of endothoracic fascia, the suprapleural membrane)
Costal pleura
Mediastinal pleura
Diaphragmatic pleura
How high does the cervical pleura project?
5 cm above top costal cartilage and 2.5cm above medial 1/3 of clavicle into base of the neck
What binds the cervical pleura anteriorly and posteriorly??
Anteriorly: the subclavian artery
Posteriorly: The neck of the 1st rib
What is the costal pleura bound by?
Back of the sternum, ribs and intercostal spaces, and sides of the bodies of T1 - T12
What is the mediastinal pleura made up of?
Reflected onto the pulmonary vessels and bronchi that forming the root of the lung form a tubular sheet around them
What does the diaphragmatic pleura cover?
Superior surface of the diaphragm except along costal attachments and where diaphragm is fused to pericardium
What are the costophragmatic recesses?
They are the 2 valleys formed by the parietal pleura next to the diaphragm and ribs
What is the function of the costophragmatic recesses?
During inspiration the inferior border of the lungs can enter those areas when the diaphragm contracts
What is the pulmonary ligament?
The parietal and visceral pleurae continue with each other around the root of the lung and form a loose cuff hanging inferiorly at the hilum. This is the pulmonary ligament
What does the pulmonary ligament do?
They provide extra space for veins to dilate when blood is returning from lung
What is the difference between hilum and root of the lung?
Hilum is the site/region containing the root of the lung. ie wedge shaped depression
Root of the lung is structure in the lung containing all the blood vessels and the bronchi
What happens to visceral and parietal pleura at the hilum?
They are fused and become continuous with each other
Where on the surface does the cervical pleura appear?
Cervical pleura is a dome shaped part of the parietal pleura that curves from sternoclavicular joint to the medial 1/3rd of the clavicle and the dome extends 2.5cm superior to 1/3rd of clavicle and 5 cm superior to the 1st costal cartilage.
What is the sternal line?
There are 2 sternal lines medially. Right and left lines which descend inferomedially and become narrower.
At what level does the sternal line become narrow?
At the level of the second costal cartilage and the manubriosternal joint
How is the left sternal line different to the right?
At the level of the 4th costal cartilage it will deviate 1 inch laterally and descend until the 6th costal cartilage
Why does the left sternal angle descend differently to the right?
Due to the heart being deviated to the left
What covers the bare area of the heart?
The pericardium is only covered by intercostal muscles ribs and skin with no pleura at the bare area of the heart.
What is the clinical significance of the bare area of the heart?
It is the only place where certain medical procedures can be performed such as cardiac centesis (fluid removed from the heart with a needle) or pericardial effusion.
What happens to lung at the location where the heart protrudes to the left?
It deviates laterally 2 cm
What is the space of deviation created between heart and lung?
Area of superficial cardiac dullness or cardiac notch
What is the area of superficial cardiac dullness used for?
can be evaluated by percussion (the sound over the lung is tested for resonance (no fluid) or dull (fluid) in the case of the area of superficial cardial dullness it can be head and located using percussion) or oscultation
What is the costodiaphragmatic line?
It lines the descent of the costodiaphragmatic pleura. This line starts right above the xiphisternal joint and passes through middle of the 7th and 8th costal cartilage at the level of the middle of the clavicle (mid-clavicular line).
The costodiaphragmatic line then passes the 10th rib at the mid-axillary line and the 12th rib at the lateral border of the erector spinae muscle and ends 2cm lateral of the spine at T12.
At what level does the costodiaphragmatic line pass through the middle of the 8th rib?
Mid-clavicular line
At what level does the costodiaphragmatic line cross the mid-axillary line?
At the level of 10th rib.
At what level does the costodiaphragmatic line pass through the 12th rib?
At the lateral border of the erector spinae
Where does the costodiaphragmatic line end?
2cm lateral to the spine of T12
Where does the vertebral/posterior line extend?
The medial edges of the pleura follow a line joining transverse processes of T1-T12 2cm away from midline on either side.
What is the costodiaphragmatic recess?
Slit-like space between costal and diaphragmatic pleurae and are the most dependent parts of the pleural cavities and the site of collection of pleural effusion
What does most dependent part of the pleural cavities mean?
Any fluid will accumulate in these areas
Where are the costomediastinal recesses located?
Slit-like space between the costal and mediastinal pleurae and lies between sternum and costal cartilages.
What is the function of the costomediastinal recesses?
The anterior border of the lung enters into it during deep inspiration
How is the lung attached to the mediastinum?
Only by the root of the lung through the blood vessels and bronchi
What surfaces do the lungs have?
Costal and mediastinal surfaces
What are the 3 borders of the lungs?
Anterior
Posterior
Inferior
What is the difference between the right and left lungs?
Right lung is broader but shorter. Left lung is narrower and longer
Right lung has 3 lobes and is divided by 2 fissures. Left lung has 2 lobes and is divided by 1 fissure
Left lung has cardiac notch at location of the heart’s apex
What fissure is present in right lung but absent in left lung?
Horizontal (transverse) fissure