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Questions and Answers
Which characteristic distinguishes the right lung from the left lung?
Which characteristic distinguishes the right lung from the left lung?
What is found at the hilum of the lung?
What is found at the hilum of the lung?
What allows the lungs to recoil to approximately 1/3 their size?
What allows the lungs to recoil to approximately 1/3 their size?
What is the primary function of the sympathetic fibers in relation to smooth muscle in the lungs?
What is the primary function of the sympathetic fibers in relation to smooth muscle in the lungs?
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Which lobes are present in the left lung?
Which lobes are present in the left lung?
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Which condition results from the presence of air in the pleural cavity?
Which condition results from the presence of air in the pleural cavity?
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What role do bronchial arteries play in the lungs?
What role do bronchial arteries play in the lungs?
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What is the role of the bronchopulmonary nodes in relation to lymphatic drainage?
What is the role of the bronchopulmonary nodes in relation to lymphatic drainage?
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In cases of a penetrating wound to the thoracic wall, what causes the lung to collapse?
In cases of a penetrating wound to the thoracic wall, what causes the lung to collapse?
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Which surface of the lung is characterized by its contact with the thoracic wall?
Which surface of the lung is characterized by its contact with the thoracic wall?
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What type of fissures separate the lobes of the right lung?
What type of fissures separate the lobes of the right lung?
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Which bronchus is more likely for foreign bodies to be aspirated into, based on anatomical structure?
Which bronchus is more likely for foreign bodies to be aspirated into, based on anatomical structure?
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What best describes the composition of the lungs?
What best describes the composition of the lungs?
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Where are the vagus nerves located in relation to the root of the lung?
Where are the vagus nerves located in relation to the root of the lung?
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Which of the following plexuses is composed of both sympathetic and parasympathetic fibers?
Which of the following plexuses is composed of both sympathetic and parasympathetic fibers?
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Which of the following structures normally accompany the vagus nerve in the carotid sheath?
Which of the following structures normally accompany the vagus nerve in the carotid sheath?
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Which sympathetic fibers pass through cardiopulmonary splanchnic nerves?
Which sympathetic fibers pass through cardiopulmonary splanchnic nerves?
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Which of the following nerves is NOT a part of the vagus nerve's pathway?
Which of the following nerves is NOT a part of the vagus nerve's pathway?
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Which of the following is NOT typically innervated by the vagus nerve?
Which of the following is NOT typically innervated by the vagus nerve?
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What is the primary effect of the vagus nerve on the heart?
What is the primary effect of the vagus nerve on the heart?
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What is the primary cause of pulmonary embolism?
What is the primary cause of pulmonary embolism?
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Which statement about the right main bronchus is accurate?
Which statement about the right main bronchus is accurate?
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What is a potential consequence of a medium-sized embolus blocking an artery in the lungs?
What is a potential consequence of a medium-sized embolus blocking an artery in the lungs?
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What is the primary role of the phrenic nerve in relation to lung cancer?
What is the primary role of the phrenic nerve in relation to lung cancer?
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What happens when there is a large atrial septal defect (ASD)?
What happens when there is a large atrial septal defect (ASD)?
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What is the main cause of myocardial infarction (MI)?
What is the main cause of myocardial infarction (MI)?
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What is the purpose of coronary bypass surgery?
What is the purpose of coronary bypass surgery?
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Which of the following is associated with Horner’s Syndrome due to lung cancer?
Which of the following is associated with Horner’s Syndrome due to lung cancer?
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Which structure is located in the anterior part of the inferior mediastinum?
Which structure is located in the anterior part of the inferior mediastinum?
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What is the primary content of the middle portion of the inferior mediastinum?
What is the primary content of the middle portion of the inferior mediastinum?
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Which of these structures is found in the posterior mediastinum?
Which of these structures is found in the posterior mediastinum?
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What is the function of the thoracic duct?
What is the function of the thoracic duct?
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Which nerves are primarily located in the posterior mediastinum?
Which nerves are primarily located in the posterior mediastinum?
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Which of the following vessels is part of the great vessels in the middle mediastinum?
Which of the following vessels is part of the great vessels in the middle mediastinum?
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Which sympathetic structures are found in the posterior mediastinum?
Which sympathetic structures are found in the posterior mediastinum?
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What does the sympathetic trunk primarily consist of?
What does the sympathetic trunk primarily consist of?
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What is the primary function of the thoracic duct?
What is the primary function of the thoracic duct?
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Where does the right lymphatic duct empty?
Where does the right lymphatic duct empty?
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Which structure forms a collateral pathway for blood flow to the heart?
Which structure forms a collateral pathway for blood flow to the heart?
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What distinguishes the parietal pleura from the visceral pleura?
What distinguishes the parietal pleura from the visceral pleura?
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What is the purpose of pleural fluid in the pleural cavity?
What is the purpose of pleural fluid in the pleural cavity?
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Which of the following is NOT a component of the parietal pleura?
Which of the following is NOT a component of the parietal pleura?
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What is characteristic of the thoracic duct's appearance?
What is characteristic of the thoracic duct's appearance?
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Which of these veins does NOT communicate with the azygos system?
Which of these veins does NOT communicate with the azygos system?
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Study Notes
Posterior Mediastinum, Pleural Cavity & Lungs
- The posterior mediastinum is located posterior to the pericardium and diaphragm
- The posterior mediastinum contains various structures, including main bronchi, vagus nerves, thoracic (descending) aorta, esophagus, azygos venous system, sympathetic trunk, and thoracic duct
- The thoracic duct is the largest lymphatic channel in the body
- The thoracic duct conveys most lymph from the body to the venous system
- The thoracic duct (duck) runs between the azygos vein and the esophagus
- The appearance of the duct is described as "beaded", due to numerous valves
- The azygos system is located on each side of the vertebral column, forming a collateral pathway for the SVC and IVC
- The azygos system drains blood from the posterior walls of the thorax and abdomen and communicates with posterior intercostal veins and vertebral venous plexus which creates collateral circulation if the IVC is obstructed
- The pleural cavity contains pleural fluid and lies between the two layers of pleura
- The pleural cavity lubricates the pleural surface and allows the layers of pleura to slide smoothly over each other during respiration
- Surface tension in the pleural cavity provides cohesion that keeps the surfaces in contact, so when the thoracic wall expands, the lung will also expand and fill with air
- The potential space between parietal pleura can have fluid accumulation. This is called a pleural recess
- The pleural recesses are called cardiomediastinal and costodiaphragmatic recesses
- The lungs fill the pleural cavities during deep inspiration. During quiet inspiration and expiration parts are not occupied by the lungs and parietal pleura come into contact with each other.
Superior Mediastinum
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The superior mediastinum lies superior to the inferior thoracic aperture and diaphragm
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The superior mediastinum contains the thymus, veins, great vessels, trachea, esophagus, vagus & phrenic nerves, thoracic duct/right lymphatic duct
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The thymus is a primary lymphoid organ that produces lymphocytes, prominent during infancy and begins to diminish at puberty
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The thymus is largely composed of fat in adults
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The superior mediastinum contains the trachea, an airway that splits into primary bronchi and esophagus, food passageway
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The structure of the trachea is cartilaginous and splits into primary bronchi
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The esophagus runs between the trachea and the vertebral column
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The superior mediastinum contains the major great vessels (veins and arteries)
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The superior mediastinum contains the vagus nerves and recurrent laryngeal nerve
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The superior mediastinum contains the phrenic nerves, arise from C3, C4, C5, and are located on the lateral sides of the pericardium, anterior to the root of the lung. They are sole motor to the diaphragm and 1/3rd sensory
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The vagus nerve is located posterior to the root of the lung
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Left and right vagus nerves become anterior and posterior (LARP)
Pulmonary Cavities
- The thorax is lined by endothoracic fascia
- Each pulmonary cavity is lined by a pleural membrane (pleura), which reflects on itself to cover the surface of the lungs as well as the pulmonary cavity
- Parietal pleura lines the pulmonary cavity
- Visceral pleura lines the lungs
The Pleura
- The parietal pleura is the outermost layer of the pleural sac and is divided into costal, mediastinal, diaphragmatic, and cervical parietal pleura according to the surface they line
- The visceral pleura is the innermost layer of the pleural sac and adheres to the surface of each lung, including the fissures
Pleural Cavity
- The pleural cavity contains pleural fluid
- The pleural fluid lubricates pleural surfaces, allowing the layers to slide smoothly during respiration
- Surface tension in the pleural cavity provides cohesion that keeps the lung surfaces in contact with the thoracic wall. This allows the lungs to expand when the thoracic wall expands and to fill with air
Pleural Recesses
- Pleural recesses are potential spaces where parietal pleura can come in contact during deep inspiration
- The pleural recesses are cardiomediastinal and costodiaphragmatic recesses
The Tracheobronchial Tree
- The tracheobronchial tree begins with the trachea as the trunk
- It branches into right and left main bronchi
- Secondary branching continues into lobar bronchi followed by segmental bronchi, finally ending with bronchioles
- The patterns of this branching are highly organized within the lungs and the associated structures
The Bronchial Arteries
- Bronchial arteries supply blood to the lower trachea and structures in the root of the lung, and to the supporting tissues of the lungs
- The bronchial arteries are located at the root of the lung
- Bronchial arteries supply the respiratory bronchioles
Lungs
- Lungs are organs of respiration that oxygenate the blood
- Lungs are light, spongy, and occupy the entire pulmonary cavities
- Lungs are attached to the root of the lung and have elastic recoil
- Each lung has an apex and base and is divided into lobes by fissures resulting in varying surfaces and borders
Bronchus (Right & Left)
- The right bronchus is shorter, straighter, and wider than the left bronchus
- The right bronchus divides into three lobar bronchi (superior, middle, inferior)
- The left bronchus is longer, smaller, and more horizontal than the right bronchus
- The left bronchus divides into two lobar bronchi (superior, inferior)
Hilum of the Lung
- The hilum of the lung is a doorway area through which structures enter/exit the root of the lung
- The structures within the hilum include bronchi, pulmonary arteries (blue), pulmonary veins (red), bronchial arteries, and lymphatics
Pulmonary Circulation
- Pulmonary arteries transport low-oxygen blood from the pulmonary trunk to the lungs
- Pulmonary veins transport oxygen-rich blood from the lungs to the left atrium
- Pulmonary arteries and veins are present within the hilum of the lung
Clinical Correlations
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Apices of the lungs—The cervical pleurae and apices of the lungs pass through the superior thoracic aperture into the region of the neck. The lungs can be injured by neck wounds, or by medical procedures like dry needling in this area, which can result in Pneumothorax resulting from entry of air into the pleural cavity
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Pneumothorax—Entry of air into the pleural cavity resulting from injury or trauma leading to collapse of the lung
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Pulmonary Collapse—Normal lungs remain distended in contact with the thoracic wall due to surface tension created by the fluid between visceral and parietal pleura. If there is trauma to the chest wall, air may enter the pleural cavity, causing the lung to collapse.
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Aspiration of foreign bodies --- Aspiration is inhalation of foreign objects (small objects like coins, food etc). The right main bronchus is shorter, wider, and more vertically oriented than the left main bronchus, which makes it more likely for inhaled objects to become lodged in it.
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Pulmonary Embolism—Obstruction of a pulmonary artery by blood clot (or fat globule/air bubble) arising from lower leg (DVT), traveling to the heart and then blocking a lung's arteries (PE). This can result in partial or complete lung artery blockage, chest pain, and difficult breathing
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Lung Cancer/Pancoast Tumor—Cancer near the apex of the lung can involve nerves in the area, including phrenic, recurrent laryngeal and sympathetic trunks. Involvement can affect the diaphragm, vocal muscles, and side of the head respectively or lead to Horner's Syndrome
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Hemothorax—Collection of blood in the pleural cavity. Bleeding can occur due to damage, or injury, to the vessels in the chest area, particularly the thoracoacromial, lateral thoracic and internal thoracic arteries, and intercostal vessels
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Atrial Septal Defect (ASD)—Congenital anomaly where the opening between the atria of the heart does not close as it should. This allows a shunt or flow between the left and right atria and may overload the pulmonary vascular system.
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Description
This quiz covers the anatomy and functions of the posterior mediastinum, pleural cavity, and lungs. Key topics include the structures contained within the posterior mediastinum, the role of the thoracic duct, and the azygos venous system's importance in collateral circulation. Test your knowledge of these vital components of the thoracic cavity.
