Dissection of the Pleural Cavities and Lungs Flashcards
What are the pleurae?
Serous sacs surrounding the lungs
During breathing, what 3 thoracic dimensions vary? What is each due to?
- Vertical: diaphragm
- Lateral: intercostal muscles moving the shafts of the ribs
- Anteroposterior: intercostal muscles moving the sternum
Are the anterior ends of the ribs superior or inferior to the posterior ends?
Inferior
How does the sternum moves when the ribs elevate?
Upward and forward
How does the sternum moves when the ribs depress?
Downward and backward
Level of shaft of ribs compared to anterior and posterior ends?
Slightly inferior
Borders of pleural cavities?
- Superiorly: root of neck 3-4 cm above costal cartilage of rib 1 but not higher than its neck
- Inferiorly: just above the costal margin
- Medially: mediastinum
- Anteriorly: posterior portion of sternum but in the inferior portion the left one does not come as close as the right one because mediastinum bulges to the left
Composition of pleura?
- Single layer of flat mesothelial cells
2. Layer of supportive connective tissue
2 types of pleura? Based on what?
Based on location:
- Parietal: associated with walls of pleural cavity
- Visceral: reflected from medial wall onto and adheres to surface of lung
4 parts to the parietal pleura?
Describe each.
- Costal: related to ribs and intercostal spaces
- Diaphragmatic: covering diaphragm
- Mediastinal: covering mediastinum
- Cervical pleura: dome shaped lining the cervical extension of the pleural cavity
2 other names for cervical pleura?
- Dome of pleura
2. Pleural cupola
What is the suprapleural membrane? What is it attached to? What muscle fibers does it receive?
Dome-like layer of fascia covering the cervical pleura
Attached to medial margin of 1st rib and to transverse process of C7
Receives scalene muscles from the neck
Can you see visceral pleura on a cadaver?
NOPE
At which point do the visceral and parietal pleurae become continuous?
At the hilum of the lung
Vertebral level of hilum of the lung?
T5 to T7
What is the root of the lung?
The hilum of the lung and the structure it contains
Innervation of parietal pleura? Where would pain be felt for each?
Somatic afferent nerves:
- Costal: branches of intercostal nerves (pain in thoracic wall)
- Diaphragmatic: phrenic nerves (pain in C3-C5 dermatomes = lateral neck and supraclavicular region of shoulder) and lower intercostal nerves
- Mediastinal: phrenic nerves (pain in C3-C5 dermatomes = lateral neck and supraclavicular region of shoulder)
Describe in painful detail the inferior margin of the parietal pleura.
Margin is just above the costal margin
- Midclavicular line: rib 8
- Midaxillary line: rib 10
- More laterally: horizontal margin crossing ribs 11 and 12 to reach T12
Innervation of visceral pleura? Where is pain felt?
Autonomic nerves accompanying bronchial vessels
No pain felt, only stretch
What sensations is the parietal pleura sensitive to?
- Pain
- Touch
- Temperature
- Pressure
What are pleural recesses?
Areas where 2 layers of parietal pleura become opposed
Do the lungs completely fill the pleural cavities? What does this mean?
Nope, not in the anterior or posterior inferior regions
BUT these spaces fill during FORCED inspiration
=> potential spaces where fluid can accumulate
What are the 2 types of pleural recesses? Which are more clinically significant? Which are larger?
- Costomediastinal recesses
2. ***Costodiaphragmatic recesses
Describe the costomediastinal recesses. Larger right or left one?
Costal pleura and mediastinal pleura oppose anterior to the heart and inferior to the lung
Larger on left side overlying the heart
Describe the costodiaphragmatic recesses.
Costal pleura and diaphragmatic pleura oppose between inferior margin of lung and pleural cavity
When are pleural processes deepest?
After forceful expiration
Describe in painful detail the quiet inspiration inferior margin of the lung.
- Midclavicular line: rib 6
- Midaxillary line: rib 8
- More laterally: horizontal margin to reach T10
How many pleural recesses total?
4
What is found between the parietal pleura and the ribs?
Thoracic cavity lined with endothoracic fascia
Which lung is bigger?
Right one
Describe the 4 characteristics of each lung.
- Base on diaphragm
- Apex above rib 1 into root of neck
- 3 surfaces
- 3 borders
Describe the 3 surfaces of the lungs.
- Costal surface
- Mediastinal surface against mediastinum anteriorly and vertebral column posteriorly
- Diaphragmatic surface
Which lung surface contains the hilum?
Mediastinal surface
Describe the 3 borders of the lungs.
- Inferior: sharp and separates base from costal surface
2 and 3. Anterior (sharp) and posterior (smooth) borders separate costal surface from mediastinal surface
What is the pulmonary ligament? Functions?
A thin fold of pleura projecting inferiorly from the hilum to the mediastinum
Functions:
- Stabilizes inferior lobe
- Accommodates down and up translocations of root structures during breathing
Location of vagus nerves in relation to roots of lungs?
Posterior
Location of phrenic nerves in relation to roots of lungs?
Anterior
6 contents of roots of lungs? Include positions.
- Pulmonary artery (superior on left and posterior on right)
- 2 pulmonary veins (inferior)
- Main bronchus (posterior on left and branched with the lobar bronchus to the superior lobe and SUPERIOR ON RIGHT)
- Bronchial vessels
- Nerves
- Lymphatics
Number of lobes of right lung?
3
Number of fissures of right lung?
2
What are lung fissures?
Invaginations of visceral pleura separating the lobes
2 fissures of right lung?
- Oblique fissure separating inferior and middle/superior lobes
- Horizontal fissure separating middle and superior lobes
Location of oblique fissure of right and left lungs in quiet respiration?
Curved line from spinous process of T4 to 4th and 5th intercostal space to rib 6 anteriorly
Location of horizontal fissure of right lung in quiet respiration?
4th intercostal space from sternum to the oblique fissure over rib 5
What do the lung fissures determine clinically?
Where clinicians should listen for lung sounds
Anterior and posterior surface projections of right superior lobe?
Anterior = root of neck to above rib 4
Posterior = root of neck to above rib 6
Anterior and posterior surface projections of right middle lobe?
Anterior = top of 4th rib to medial 6th rib
Posterior = top of rib 6 to top of rib 10 medially
Anterior and posterior surface projections of right inferior lobe?
Anterior = laterally over rib 6 and 5th and 6th intercostal spaces (around nipple)
Posterior = none
6 mediastinal structures in contact with medial surface of right lung? Which form impressions on the mediastinal surface of the right lung? Structure not part of mediastinum that also forms an impression?
- Heart***
- IVC
- SVC***
- Azygos vein*** (impression from arch)
- Esophagus***
- Right brachiocephalic vein***
+ 1st rib