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Questions and Answers
Damage to which structure within the mediastinum would most severely impair lymphatic drainage from the lower half of the body and the left side of the upper body?
Damage to which structure within the mediastinum would most severely impair lymphatic drainage from the lower half of the body and the left side of the upper body?
- Phrenic nerve
- Esophagus
- Thoracic duct (correct)
- Azygos vein
A patient presents with edema and cyanosis of the face and neck. Imaging reveals a mass compressing a major vessel within the superior mediastinum. Which of the following vessels is most likely being compressed?
A patient presents with edema and cyanosis of the face and neck. Imaging reveals a mass compressing a major vessel within the superior mediastinum. Which of the following vessels is most likely being compressed?
- Pulmonary trunk
- Aortic arch
- Superior vena cava (correct)
- Brachiocephalic trunk
Following a traumatic injury, a patient exhibits signs of diaphragmatic paralysis. Which nerve, located within the mediastinum, is most likely to have been damaged?
Following a traumatic injury, a patient exhibits signs of diaphragmatic paralysis. Which nerve, located within the mediastinum, is most likely to have been damaged?
- Vagus nerve
- Cardiac nerve
- Thoracic splanchnic nerve
- Phrenic nerve (correct)
During a mediastinoscopy, a surgeon inadvertently damages a nerve resulting in hoarseness and difficulty swallowing. Which of the following nerves was most likely injured?
During a mediastinoscopy, a surgeon inadvertently damages a nerve resulting in hoarseness and difficulty swallowing. Which of the following nerves was most likely injured?
A surgeon is planning to perform a transsternal thymectomy. Through which mediastinal division will the surgeon primarily be working during this procedure?
A surgeon is planning to perform a transsternal thymectomy. Through which mediastinal division will the surgeon primarily be working during this procedure?
A patient is diagnosed with a tumor located in the posterior mediastinum. Which of the following structures is most likely to be directly affected by the tumor's growth?
A patient is diagnosed with a tumor located in the posterior mediastinum. Which of the following structures is most likely to be directly affected by the tumor's growth?
A physician suspects a patient has an abnormality affecting the heart's electrical conduction system. Which of the following mediastinal divisions would be most relevant for investigating the location of this abnormality?
A physician suspects a patient has an abnormality affecting the heart's electrical conduction system. Which of the following mediastinal divisions would be most relevant for investigating the location of this abnormality?
A patient presents with dysphagia and chest discomfort. Imaging reveals compression of the esophagus by an enlarged structure in the posterior mediastinum. Which of the following is the most likely cause?
A patient presents with dysphagia and chest discomfort. Imaging reveals compression of the esophagus by an enlarged structure in the posterior mediastinum. Which of the following is the most likely cause?
Which anatomical feature defines the superior border of the mediastinum?
Which anatomical feature defines the superior border of the mediastinum?
A patient undergoes a procedure involving the ligation of a major blood vessel within the mediastinum. To minimize the risk of compromising blood flow to the left arm, which of the following vessels should the surgeon avoid ligating?
A patient undergoes a procedure involving the ligation of a major blood vessel within the mediastinum. To minimize the risk of compromising blood flow to the left arm, which of the following vessels should the surgeon avoid ligating?
During an autopsy, the pathologist notes significant atrophy of an organ located in both the superior and anterior mediastinum. This finding most likely involves which of the following structures?
During an autopsy, the pathologist notes significant atrophy of an organ located in both the superior and anterior mediastinum. This finding most likely involves which of the following structures?
A surgeon is preparing to perform a complex cardiac procedure requiring access to the roots of the great vessels. Which mediastinal division will provide the primary surgical field for this procedure?
A surgeon is preparing to perform a complex cardiac procedure requiring access to the roots of the great vessels. Which mediastinal division will provide the primary surgical field for this procedure?
A patient exhibits an abnormal widening of the mediastinum on a chest radiograph following a high-speed motor vehicle accident. Which of the following is the most concerning potential cause?
A patient exhibits an abnormal widening of the mediastinum on a chest radiograph following a high-speed motor vehicle accident. Which of the following is the most concerning potential cause?
Damage to the pericardium would have the MOST direct impact on the function of which structure?
Damage to the pericardium would have the MOST direct impact on the function of which structure?
If the transverse thoracic plane is located via external landmarks, which of the following intervertebral discs would be directly posterior to that plane?
If the transverse thoracic plane is located via external landmarks, which of the following intervertebral discs would be directly posterior to that plane?
Flashcards
Mediastinum
Mediastinum
The central compartment of the thoracic cavity, between the pleural sacs.
Transverse Thoracic Plane
Transverse Thoracic Plane
Imaginary plane dividing the mediastinum into superior and inferior sections, running from the sternal angle to the T4/T5 intervertebral disc.
Superior Mediastinum
Superior Mediastinum
Houses the thymus, great vessels (aortic arch, brachiocephalic trunk, left common carotid artery, left subclavian artery, superior vena cava, brachiocephalic veins), vagus and phrenic nerves, trachea, esophagus, and thoracic duct.
Anterior Mediastinum
Anterior Mediastinum
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Middle Mediastinum
Middle Mediastinum
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Posterior Mediastinum
Posterior Mediastinum
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Mediastinum Boundaries
Mediastinum Boundaries
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Fibrous Pericardium
Fibrous Pericardium
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Serous Pericardium
Serous Pericardium
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Aorta (in Mediastinum)
Aorta (in Mediastinum)
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Superior Vena Cava
Superior Vena Cava
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Inferior Vena Cava
Inferior Vena Cava
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Trachea (in Mediastinum)
Trachea (in Mediastinum)
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Esophagus (in Mediastinum)
Esophagus (in Mediastinum)
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Phrenic Nerve
Phrenic Nerve
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Study Notes
- The mediastinum is the central compartment of the thoracic cavity
- It sits between the lungs' pleural sacs
- It spans from the superior thoracic aperture to the diaphragm
- It stretches from the sternum and costal cartilages (anteriorly) to the thoracic vertebrae (posteriorly)
Divisions of the Mediastinum
- The mediastinum is separated into superior and inferior sections by an imaginary plane
- This plane runs from the sternal angle to the T4/T5 intervertebral disc
- The inferior mediastinum has three parts: anterior, middle, and posterior
Superior Mediastinum
- It runs from the superior thoracic aperture to the transverse thoracic plane
- It features the thymus, great vessels, vagus and phrenic nerves, trachea, esophagus, and thoracic duct
Anterior Mediastinum
- This is located between the sternum and the pericardium
- It features the thymus, fat, connective tissue, some lymph nodes, and internal thoracic vessel branches
Middle Mediastinum
- It features the pericardium, heart, great vessel roots, phrenic nerves, and main bronchi
Posterior Mediastinum
- It sits behind the pericardium and in front of T5-T12 vertebral bodies
- It features the esophagus, vagus nerves, thoracic duct, azygos and hemiazygos veins, sympathetic trunks, and lymph nodes
Boundaries of the Mediastinum
- Superior boundary: Superior thoracic aperture
- Inferior boundary: Diaphragm
- Anterior boundary: Sternum and costal cartilages
- Posterior boundary: Thoracic vertebrae
- Lateral boundary: Mediastinal pleura of the lungs
Contents of the Mediastinum
- Heart and pericardium
- Great vessels: aorta, pulmonary trunk, superior and inferior vena cava, brachiocephalic vessels
- Trachea and esophagus
- Thymus gland
- Nerves: vagus, phrenic, cardiac
- Lymph nodes and lymphatic vessels
- Thoracic duct
- Fat and connective tissue
Heart and Pericardium
- The heart is located in the middle mediastinum
- It is enclosed by the pericardium
- The fibrous pericardium, attached to the diaphragm and sternum, forms the outer layer
- The serous pericardium includes parietal and visceral (epicardium) layers
- The pericardial cavity lies between the parietal and visceral serous pericardium layers
Great Vessels
- The ascending aorta, aortic arch, and descending aorta are within the mediastinum
- The pulmonary trunk starts at the right ventricle and splits into pulmonary arteries (right and left)
- The superior vena cava returns blood from the upper body to the right atrium
- The inferior vena cava returns blood from the lower body to the right atrium
- Brachiocephalic vessels: brachiocephalic trunk, left common carotid, and left subclavian arteries
- Brachiocephalic veins form from the internal jugular and subclavian veins
Trachea and Esophagus
- The trachea is in the superior mediastinum, bifurcating into main bronchi at the sternal angle
- The esophagus sits behind the trachea through the superior and posterior mediastinum, passing through the diaphragm
Thymus Gland
- The thymus is in the superior and anterior mediastinum
- It's important for T-cell maturation
- It's large in infants/children but shrinks after puberty
Nerves
- The vagus nerve (CN X) runs through the superior and posterior mediastinum, providing parasympathetic innervation to thoracic and abdominal viscera
- The phrenic nerve (C3-C5) runs through the superior and middle mediastinum, innervating the diaphragm
- Cardiac nerves arise from the sympathetic trunk, providing sympathetic innervation to the heart
Lymph Nodes and Lymphatic Vessels
- Numerous lymph nodes are located throughout the mediastinum
- They drain lymph from the thoracic organs
- The thoracic duct passes through the posterior mediastinum, draining lymph from the lower body and left upper body; it's the largest lymphatic vessel
Thoracic Duct
- Collects lymph from most of the body
- Ascends through the posterior mediastinum
- Empties into the left subclavian vein
Clinical Significance
- Mediastinitis: Mediastinum inflammation, often from esophageal rupture or post-surgical infection
- Mediastinal tumors can arise from tissues like the thymus, lymph nodes, or nerve tissue
- Mediastinal shift: Mediastinum displacement, often from tension pneumothorax or large pleural effusion
- Superior vena cava syndrome: Obstruction causing edema/cyanosis in the face, neck, and upper extremities
- Aortic dissection: A tear in the aorta's wall that can extend into the mediastinum
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Description
Overview of the mediastinum, the central compartment of the thoracic cavity. Covers its location, divisions (superior and inferior), and the contents of the superior mediastinum. Includes information on the thymus, great vessels, nerves, trachea, esophagus, and thoracic duct.
