Organization of Thoracic Viscera

Question 1

What passes through the superior thoracic aperture?

Answer 1

Trachea, esophagus, as well as many vessels and nerves

Question 2

What are the boundaries of the superior thoracic aperture?

Answer 2

First thoracic vertebra
First pair of ribs and costal cartilages
Superior margin of the manubrium sterni

Question 3

What are the boundaries of the inferior thoracic aperture?

Answer 3

12th thoracic vertebrae
Costal margin
Xiphosternal joint

Question 4

What is the suprapleural membrane?

Answer 4

Thickening of endothoracic fascia above superior thoracic aperture that prevents bulging of lungs into neck

Question 5

Where are the parietal and visceral pleura of the lungs continuous with each other in the thoracic cavity?

Answer 5

They are continuous with each other around the root of the lung

Question 6

What are the 4 divisions of the parietal pleura based on the location?

Answer 6

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

Question 7

What is the pulmonary ligament?

Answer 7

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.

Question 8

What limits the pleural cavities? What are contained within the pleural cavities?

Answer 8

Pleural cavities are limited by the pleural reflections between mediastinal pleura and diaphragmatic pleura
The lungs are contained in the pleural cavity.

Question 9

What does the right and left pleura deviate out laterally?

Answer 9

At the xiphosternal joint (7th rib)

Question 10

At what level of costal cartilage does the left pleura deviate to create the shallow notch called the bare area?

Answer 10

At level of 4th costal cartilage. The bare area is important for pericardiocentesis

Question 11

What are the lower borders of the pleural reflections for both right and left?

Answer 11

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

Question 12

What are the lower borders of the lungs with respect to the ribs?

Answer 12

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

Question 13

What is a pleural recess?

Answer 13

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.

Question 14

What are the 2 major pleural recesses, and what two pleura form them?

Answer 14

Costodiaphragmatic recess: at the reflection of costal pleura onto diaphragmatic pleura
Costamediastinal recess: At the anterior reflections of costal pleura onto mediastinal pleura

Question 15

Which recess does the lingula enter during maximal inspiration?

Answer 15

Left costomediastinal recess (larger on left rather than right because of the cardiac notch)

Question 16

At which thoracic vertebra is the superior and inferior mediastinum separated?

Answer 16

4th thoracic vertebra

Question 17

What limits the superior mediastinum superiorly? What limits the inferior mediastinum inferiorly?

Answer 17

Superior mediastinum is limited superiorly by the superior thoracic aperture
Inferior mediastinum is limited inferiorly by the diaphragm

Question 18

What portions is the inferior mediastinum separated into?

Answer 18

The anterior mediastinum, the middle mediastinum, and the posterior mediastinum

Question 19

Which mediastinum contains the pericardial sac and its contents?

Answer 19

The middle mediastinum

Question 20

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?

Answer 20

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
7. Trachea
8. Esophagus
9. Thoracic duct
10. Lymph nodes

Question 21

Where is the posterior mediastinum located, and what are the 6 main contents of the posterior mediastinum (part of the inferior mediastinum)

Answer 21

Located behind pericardial sac from 5th through 12th thoracic vertebrae

1. Esophagus
2. Thoracic aorta
3. Thoracic sympathetic trunks
4. Thoracic splanchnic nerves
5. Thoracic duct
6. Azygous system of veins

Question 22

What lies in front, the trachea or esophagus? When does trachea bifurcate?

Answer 22

The trachea lies in front of the esophagus, and bifurcates behind the sternal angle (junction of sternum and manubrium)

Question 23

What crosses the trachea and esophagus on the right and left at the root of the lung?

Answer 23

The azygous vein crosses the esophagus and trachea on the right
the aortic arch crosses the esophagus and trachea on the left

Question 24

Describe the path of the arch of the aorta including where it starts and ends.

Answer 24

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.

Question 25

What two structures are contained in the concavity of the aortic arch?

Answer 25

right pulmonary artery and the left principal bronchus

Question 26

What vein crosses the 3 branches of the aorta anteriorly?

Answer 26

The left brachiocephalic vein

Question 27

What are the three branches of the aorta, from right to left?

Answer 27

the brachiocephalic trunk left common carotid left subclavian

Question 28

When does the brachiocephalic trunk divide? Where does the left common carotid enter the neck?

Answer 28

Behind the right side of the sternoclavicular joint | Left common carotid enters the neck behind the left sternoclavicular joint

Question 29

What is coarctation of the aorta?

Answer 29

Narrowing of the aortic arch beyond the left subclavian branch. To compensate, body creates anastomotic channels

Question 30

What are the anastomotic channels of the aorta during coarctation of the aorta?

Answer 30

Subclavian arteries -> internal thoracic arteries -> anterior intercostal arteries -> posterior intercostal arteries - descending aorta (beyond the site of constriction)

Question 31

What is the consequence of coarctation of the aorta on the intercostal arterie and the ribs?

Answer 31

Dilates the anterior intercostal arteries and causes notching of the ribs due to arteries pressing up against the ribs

Question 32

What two veins give rise to the brachiocephalic veins? Where does this occur?

Answer 32

The jugular veins and the subclavian veins feed into the brachiocephalic veins. This occurs on the right and left sternoclavicular joints

Question 33

What do the left and right brachiocephalic veins join together to form? Where does this occur?

Answer 33

Joins together into the superior vena cava, and this occurs behind the sternal end of the first costal cartilage

Question 34

What veins are received by the superior vena cava prior to entering the right atrium?

Answer 34

Left and right brachiocephalic veins as well as the azygous vein

Question 35

Where can the vagus nerve be found in the root of the neck?

Answer 35

The vagus nerve lies between the internal jugular vein and the common carotid arteries in the neck

Question 36

Where does the vagus nerve pass the root of the lung, anterior or posterior to it?

Answer 36

The vagus descends behind (posterior) the root of the lungs

Question 37

At which point does the left recurrent laryngeal nerve return upward? Which mediastinum is it in?

Answer 37

It hooks on the left side of the arch of the aorta behind the ligamentum arteriosum

Question 38

At which point does the right recurrent laryngeal nerve return upward? Which mediastinum is it in?

Answer 38

The right recurrently laryngeal nerve hooks around the right subclavian artery in the root of the neck. It is not found in the mediastinum.

Question 39

Which ventral rami form the phrenic nerve?

Answer 39

C3, C4, and C5 (keep the diaphragm alive)

Question 40

Between which two vessels do the phrenic nerves enter the superior mediastinum? How do they descend with respect to the vagus nerve?

Answer 40

They pass between the subclavian artery and vein and lateral to vagus nerve

Question 41

Does the phrenic nerve pass in front of or behind the root of the lung?

Answer 41

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

Question 42

What are the somatic efferent targets of the phrenic nerve? What are the somatic afferents (where pain and sensory information is relayed)?

Answer 42

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)

Question 43

When does the esophagus begin, and when does it pass through the diaphragm (which vertebrae)?

Answer 43

Esophagus begins as a continuation of pharynx | Esophagus passes through diaphragm at T10 (crosses over aorta to the left before passing through diaphragm)

Question 44

What are the 4 esophageal constrictions (superior to inferior)?

Answer 44

Begin with ABcD: Where pharynx joins (begins) Aortic arch (A) Left principal bronchus (B) When it pierces diaphragm at T10 (D)

Question 45

What are the two trunks of the esophageal plexus? Which nerve turns into the esophageal plexus?

Answer 45

Creates the anterior vagal trunk and posterior vagal trunk. Esophageal plexus forms when vagus nerve reaches esophagus

Question 46

When the descending thoracic aorta passes through the diaphragm, at which vertebrae does this occur?

Answer 46

T12

Question 47

What is the name of the system of veins on the right and left side of the body wall?

Answer 47

Azygous on the right | Hemiazygous and accessory hemiazygous on the left

Question 48

What begins the thoracic duct in the abdomen before it passes up?

Answer 48

Cyterna chyli

Question 49

The thoracic duct passes on the right side of the aorta. When does the thoracic duct cross towards the left (at which vertebrae)?

Answer 49

T5