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Questions and Answers
Which of the following structures might be compressed by a thoracic aortic aneurysm, resulting in hoarseness?
Which of the following structures might be compressed by a thoracic aortic aneurysm, resulting in hoarseness?
Which of the following is a direct branch of the intercostal arteries?
Which of the following is a direct branch of the intercostal arteries?
Which of the following is NOT a branch of the thoracic aorta?
Which of the following is NOT a branch of the thoracic aorta?
What condition is most commonly associated with aneurysms of the ascending aorta?
What condition is most commonly associated with aneurysms of the ascending aorta?
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Why is the anterior radiculomedullary artery (of Adamkiewicz) considered important in the context of the thoracic aorta?
Why is the anterior radiculomedullary artery (of Adamkiewicz) considered important in the context of the thoracic aorta?
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What is the typical treatment for a large abdominal aortic aneurysm (AAA)?
What is the typical treatment for a large abdominal aortic aneurysm (AAA)?
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What is the most common location for a thoracic aortic aneurysm?
What is the most common location for a thoracic aortic aneurysm?
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Which of the following statements regarding the blood supply to the esophagus is TRUE?
Which of the following statements regarding the blood supply to the esophagus is TRUE?
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What is the primary function of the azygos system of veins?
What is the primary function of the azygos system of veins?
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What is the most accurate anatomical description of the thoracic duct?
What is the most accurate anatomical description of the thoracic duct?
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Which of the following accurately describes the relationship between the descending thoracic aorta and the esophagus?
Which of the following accurately describes the relationship between the descending thoracic aorta and the esophagus?
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At what vertebral level does the descending thoracic aorta traverse the diaphragm?
At what vertebral level does the descending thoracic aorta traverse the diaphragm?
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The costocervical trunk, a branch of the subclavian artery, gives rise to which of the following vessels?
The costocervical trunk, a branch of the subclavian artery, gives rise to which of the following vessels?
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What is the significance of the descending thoracic aorta's trajectory towards the midline as it descends?
What is the significance of the descending thoracic aorta's trajectory towards the midline as it descends?
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What is the primary function of the sympathetic chain in the posterior mediastinum?
What is the primary function of the sympathetic chain in the posterior mediastinum?
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Which of the following structures is NOT directly located in the posterior mediastinum?
Which of the following structures is NOT directly located in the posterior mediastinum?
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Flashcards
Intercostal arteries
Intercostal arteries
Blood vessels supplying the intercostal spaces, important for thoracic blood supply.
Anterior radiculomedullary artery
Anterior radiculomedullary artery
Also known as the artery of Adamkiewicz, it's a major blood supply to the spinal cord from the aorta.
Bronchial arteries
Bronchial arteries
Arteries that supply blood to the bronchial tubes, branching from the aorta or intercostal arteries.
Unpaired branches of the aorta
Unpaired branches of the aorta
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Thoracic aortic aneurysm
Thoracic aortic aneurysm
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Abdominal aortic aneurysm (AAA)
Abdominal aortic aneurysm (AAA)
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Symptoms of thoracic aortic dissection
Symptoms of thoracic aortic dissection
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Treatment for large abdominal aneurysms
Treatment for large abdominal aneurysms
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Azygos system of veins
Azygos system of veins
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Thoracic duct
Thoracic duct
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Sympathetic chain
Sympathetic chain
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Descending thoracic aorta
Descending thoracic aorta
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Costocervical trunk
Costocervical trunk
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Esophagus
Esophagus
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Intercostal vessels
Intercostal vessels
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Vagus nerves
Vagus nerves
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Study Notes
Practical 5: Posterior Mediastinum & Review
- Objectives: Identify and describe the azygos system of veins, the anatomy and course of the thoracic duct, and the sympathetic chain.
- Posterior Mediastinum Contents: Descending thoracic aorta, azygos & hemiazygos veins, thoracic duct, esophagus, sympathetic trunk, intercostal vessels (posterior), and vagus nerves.
Azygos System of Veins
- The arrangement of azygos veins is variable.
- The azygos system connects to thoracic, abdominal, and back veins.
- These connections provide alternative drainage routes if the superior vena cava (SVC) or inferior vena cava (IVC) are blocked.
- Accessory hemiazygos and hemiazygos veins cross over vertebrae T7 and T9 to join the azygos vein.
Thoracic Duct
- Lymph from the right thorax, upper limb, head, and neck drains into the right lymphatic duct.
- The rest of the body's lymph drains into the thoracic duct.
- Lymph trunks drain into corresponding venous angles (junction of internal jugular and subclavian veins).
- Chyle (fatty lymph) from the intestines enters the cisterna chyli at the L1 level, then drains into the thoracic duct.
- The thoracic duct ascends through the aortic hiatus, anterior to the vertebrae, between the azygos vein and the esophagus/aorta.
- It veers to the left at T4/5 level and drains into the left venous angle.
Sympathetic Chain
- The sympathetic chain originates from T1 to L2 spinal nerves.
- It's needed at every spinal level to innervate tissues.
- Paravertebral sympathetic ganglia run parallel to the spinal cord, alongside the vertebrae.
- Sympathetic nerves enter at T1-L2, travel up and down, and connect with other spinal nerves to reach their targets.
- Nerves leave the T1-L2 ventral rami and join the chain via white rami communicantes.
- Nerves leave the chain and join spinal nerves via gray rami communicantes.
- White rami are myelinated, and grey rami are unmyelinated.
- There are only three pairs of cervical ganglia due to the merging of the original eight cervical ganglia.
- The most inferior ganglion is called the ganglion impar.
- This ganglion fuses with its counterpart in the midline.
Descending Thoracic Aorta
- The descending thoracic aorta runs from T4 to T12, posterior to the root of the left lung and esophagus.
- It descends toward the midline and passes through the aortic hiatus of the diaphragm at the T12 level.
Descending Thoracic Aorta: Branches
- Costocervical trunk (branch of subclavian artery) gives off a superior intercostal branch.
- Posterior and subcostal arteries run from T3 to T11.
- Bronchial arteries arise indirectly from posterior intercostal arteries (right side).
- Unpaired branches arising anteriorly supply esophageal, mediastinal tissues, and lymph nodes (pericardial).
- Superior phrenic arteries, paired, run on the superior surface of the diaphragm.
Thoracic Aortic Aneurysms & Aortic Dissection
- An aneurysm is a ballooning of a weakened part of the aorta.
- Thoracic aneurysms are less common than abdominal aortic aneurysms (AAAs).
- Older men are more likely to have AAAs (6% risk) than older women (1% risk).
- Risk factors include atherosclerosis, high blood pressure (hypertension), trauma, and connective tissue disorders like Marfan's syndrome.
Aortic Dissection
- Aortic dissection involves a tear in the tunica intima, allowing blood into the intima-media space.
- The tear propagates, creating a rapidly expanding false lumen.
- This is often accompanied by sudden, tearing chest pain.
Pancoast Tumour and Compression of Sympathetic Trunk
- Lung cancer in the apex of the lung (Pancoast tumor) can compress the brachial plexus and upper T1 sympathetics.
- This can cause shoulder pain and potential upper limb pain/weakness.
- Compression of upper sympathetics can lead to Horner's syndrome (miosis, ptosis, anhidrosis).
Oesophagus
- The esophagus is located posterior to the trachea, pericardium, and left atrium.
- It descends toward the left and then deviates to the left.
- The esophageal plexus is formed by vagus nerves (parasympathetic) and sympathetic nerves from the sympathetic trunk.
- These nerves form anterior and posterior vagal trunks that pass through the esophageal hiatus at the T10 level.
Dysphagia (difficulty swallowing)
- Dysphagia is investigated via fluoroscopy and barium swallow.
- Problems like tumors, ulcers, or esophageal webs can cause compression or narrowing of the esophagus, making swallowing difficult.
- Hiatal hernias occur when a part of the stomach herniates through the diaphragm.
Tracheoesophageal Fistula & Oesophageal Atresia
- Developmental issues in the septum separating tracheal & esophageal development can cause the conditions.
- These conditions often involve abnormal connections (fistula) and/or blocked passages (atresia).
- These conditions may be fatal without early surgical intervention.
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Description
This quiz focuses on the anatomy of the posterior mediastinum, including the azygos system of veins, thoracic duct, and sympathetic chain. Learn about the structures such as the descending thoracic aorta, intercostal vessels, and vagus nerves. Test your knowledge of this essential component of thoracic anatomy.
