Flashcards in Organization of Thoracic Viscera Deck (49)
What passes through the superior thoracic aperture?
Trachea, esophagus, as well as many vessels and nerves
What are the boundaries of the superior thoracic aperture?
First thoracic vertebra
First pair of ribs and costal cartilages
Superior margin of the manubrium sterni
What are the boundaries of the inferior thoracic aperture?
12th thoracic vertebrae
What is the suprapleural membrane?
Thickening of endothoracic fascia above superior thoracic aperture that prevents bulging of lungs into neck
Where are the parietal and visceral pleura of the lungs continuous with each other in the thoracic cavity?
They are continuous with each other around the root of the lung
What are the 4 divisions of the parietal pleura based on the location?
1. Costal pleura - lines thoracic wall
2. Cervical pleura (cupola) - extends through thoracic inlet into the neck
3. Diaphragmatic pleura - covers the diaphragm
4. Mediastinal pleura - covers the mediastinal surface of each pleural sac
What is the pulmonary ligament?
The reflection of the mediastinal parietal pleura at root of lung where it sags below the hilus of the lung; creates a double layer of pleura.
What limits the pleural cavities? What are contained within the pleural cavities?
Pleural cavities are limited by the pleural reflections between mediastinal pleura and diaphragmatic pleura
The lungs are contained in the pleural cavity.
What does the right and left pleura deviate out laterally?
At the xiphosternal joint (7th rib)
At what level of costal cartilage does the left pleura deviate to create the shallow notch called the bare area?
At level of 4th costal cartilage. The bare area is important for pericardiocentesis
What are the lower borders of the pleural reflections for both right and left?
The pleural reflection crosses the 8th rib at the midclavicular line
Crosses the 10th rib at the mid axillary line
Crosses the 12th rib adjacent to the vertebral border on the posterior surface
What are the lower borders of the lungs with respect to the ribs?
The lungs cross the 6th rib at the midclavicular line
cross the 8th rib at the mid-axillary line
Crosses 10th rib adjacent to vertebral border posteriorly
What is a pleural recess?
The portions of parietal pleura where the lungs do not reach into, so the parietal pleura are touching, as the lungs do not fill the pleural cavity.
What are the 2 major pleural recesses, and what two pleura form them?
Costodiaphragmatic recess: at the reflection of costal pleura onto diaphragmatic pleura
Costamediastinal recess: At the anterior reflections of costal pleura onto mediastinal pleura
Which recess does the lingula enter during maximal inspiration?
Left costomediastinal recess (larger on left rather than right because of the cardiac notch)
At which thoracic vertebra is the superior and inferior mediastinum separated?
4th thoracic vertebra
What limits the superior mediastinum superiorly? What limits the inferior mediastinum inferiorly?
Superior mediastinum is limited superiorly by the superior thoracic aperture
Inferior mediastinum is limited inferiorly by the diaphragm
What portions is the inferior mediastinum separated into?
The anterior mediastinum, the middle mediastinum, and the posterior mediastinum
Which mediastinum contains the pericardial sac and its contents?
The middle mediastinum
Where is the superior mediastinum located respective to vertebrae and the anterior thoracic wall, and what are the 10 main contents of the superior mediastinum from anterior to posterior?
Located behind manubriosterni and the first 4 thoracic vertebrae
1. Thymus gland
2. Brachiocephalic veins and superior vena cava
3. Aortic arch and three branches
4. Vagus and phrenic nerves
5. Cardiac plexus of nerves
6. Left recurrent laryngeal nerve
9. Thoracic duct
10. Lymph nodes
Where is the posterior mediastinum located, and what are the 6 main contents of the posterior mediastinum (part of the inferior mediastinum)
Located behind pericardial sac from 5th through 12th thoracic vertebrae
2. Thoracic aorta
3. Thoracic sympathetic trunks
4. Thoracic splanchnic nerves
5. Thoracic duct
6. Azygous system of veins
What lies in front, the trachea or esophagus? When does trachea bifurcate?
The trachea lies in front of the esophagus, and bifurcates behind the sternal angle (junction of sternum and manubrium)
What crosses the trachea and esophagus on the right and left at the root of the lung?
The azygous vein crosses the esophagus and trachea on the right
the aortic arch crosses the esophagus and trachea on the left
Describe the path of the arch of the aorta including where it starts and ends.
Aortic arch starts on the right of the sternal angle, crosses to the left over the esophagus and trachea, passes downward to the left of trachea and esophagus, ending at the left side of the sternal angle.
What two structures are contained in the concavity of the aortic arch?
right pulmonary artery and the left principal bronchus
What vein crosses the 3 branches of the aorta anteriorly?
The left brachiocephalic vein
What are the three branches of the aorta, from right to left?
the brachiocephalic trunk
left common carotid
When does the brachiocephalic trunk divide? Where does the left common carotid enter the neck?
Behind the right side of the sternoclavicular joint
Left common carotid enters the neck behind the left sternoclavicular joint
What is coarctation of the aorta?
Narrowing of the aortic arch beyond the left subclavian branch. To compensate, body creates anastomotic channels
What are the anastomotic channels of the aorta during coarctation of the aorta?
Subclavian arteries -> internal thoracic arteries -> anterior intercostal arteries -> posterior intercostal arteries - descending aorta (beyond the site of constriction)
What is the consequence of coarctation of the aorta on the intercostal arterie and the ribs?
Dilates the anterior intercostal arteries and causes notching of the ribs due to arteries pressing up against the ribs
What two veins give rise to the brachiocephalic veins? Where does this occur?
The jugular veins and the subclavian veins feed into the brachiocephalic veins. This occurs on the right and left sternoclavicular joints
What do the left and right brachiocephalic veins join together to form? Where does this occur?
Joins together into the superior vena cava, and this occurs behind the sternal end of the first costal cartilage
What veins are received by the superior vena cava prior to entering the right atrium?
Left and right brachiocephalic veins as well as the azygous vein
Where can the vagus nerve be found in the root of the neck?
The vagus nerve lies between the internal jugular vein and the common carotid arteries in the neck
Where does the vagus nerve pass the root of the lung, anterior or posterior to it?
The vagus descends behind (posterior) the root of the lungs
At which point does the left recurrent laryngeal nerve return upward? Which mediastinum is it in?
It hooks on the left side of the arch of the aorta behind the ligamentum arteriosum
At which point does the right recurrent laryngeal nerve return upward? Which mediastinum is it in?
The right recurrently laryngeal nerve hooks around the right subclavian artery in the root of the neck. It is not found in the mediastinum.
Which ventral rami form the phrenic nerve?
C3, C4, and C5 (keep the diaphragm alive)
Between which two vessels do the phrenic nerves enter the superior mediastinum? How do they descend with respect to the vagus nerve?
They pass between the subclavian artery and vein and lateral to vagus nerve
Does the phrenic nerve pass in front of or behind the root of the lung?
Passes in front of the root of the lungs (may be one of the few important structures to pass in front of the root of the lungs
What are the somatic efferent targets of the phrenic nerve? What are the somatic afferents (where pain and sensory information is relayed)?
The somatic efferent is the diaphragm.
The somatic afferent includes the fibrous and parietal serous pericardium, mediastinal parietal pleura, and the central part of the diaphragm (diaphragmatic parietal pleura and the parietal peritoneum)
When does the esophagus begin, and when does it pass through the diaphragm (which vertebrae)?
Esophagus begins as a continuation of pharynx
Esophagus passes through diaphragm at T10 (crosses over aorta to the left before passing through diaphragm)
What are the 4 esophageal constrictions (superior to inferior)?
Begin with ABcD:
Where pharynx joins (begins)
Aortic arch (A)
Left principal bronchus (B)
When it pierces diaphragm at T10 (D)
What are the two trunks of the esophageal plexus? Which nerve turns into the esophageal plexus?
Creates the anterior vagal trunk and posterior vagal trunk. Esophageal plexus forms when vagus nerve reaches esophagus
When the descending thoracic aorta passes through the diaphragm, at which vertebrae does this occur?
What is the name of the system of veins on the right and left side of the body wall?
Azygous on the right
Hemiazygous and accessory hemiazygous on the left
What begins the thoracic duct in the abdomen before it passes up?