Podcast
Questions and Answers
What is the primary function of the azygos system of veins?
What is the primary function of the azygos system of veins?
At what vertebral level does the descending thoracic aorta run?
At what vertebral level does the descending thoracic aorta run?
Which structure is primarily responsible for sympathetic nervous system responses in the thorax?
Which structure is primarily responsible for sympathetic nervous system responses in the thorax?
The thoracic duct is responsible for draining lymph from which primary areas?
The thoracic duct is responsible for draining lymph from which primary areas?
Signup and view all the answers
Which of the following veins is NOT part of the azygos system?
Which of the following veins is NOT part of the azygos system?
Signup and view all the answers
The course of the descending thoracic aorta is mainly posterior to which structure?
The course of the descending thoracic aorta is mainly posterior to which structure?
Signup and view all the answers
Which branch of the subclavian artery gives rise to the supreme intercostal artery?
Which branch of the subclavian artery gives rise to the supreme intercostal artery?
Signup and view all the answers
The vagus nerves primarily influence which system within the thorax?
The vagus nerves primarily influence which system within the thorax?
Signup and view all the answers
Which arteries are responsible for supplying the spinal cord?
Which arteries are responsible for supplying the spinal cord?
Signup and view all the answers
What is the most common type of aortic aneurysm?
What is the most common type of aortic aneurysm?
Signup and view all the answers
Which of the following complications can arise from a thoracic aortic aneurysm?
Which of the following complications can arise from a thoracic aortic aneurysm?
Signup and view all the answers
Which arteries supply the areaolar tissues and lymph nodes in the mediastinum?
Which arteries supply the areaolar tissues and lymph nodes in the mediastinum?
Signup and view all the answers
What is the treatment approach for large abdominal aortic aneurysms?
What is the treatment approach for large abdominal aortic aneurysms?
Signup and view all the answers
Which of the following arteries is NOT a direct branch of the thoracic aorta?
Which of the following arteries is NOT a direct branch of the thoracic aorta?
Signup and view all the answers
Which arteries contribute to the blood supply of the diaphragm?
Which arteries contribute to the blood supply of the diaphragm?
Signup and view all the answers
What percentage of thoracic aortic aneurysms occur in older men and women?
What percentage of thoracic aortic aneurysms occur in older men and women?
Signup and view all the answers
Flashcards
Azygos System
Azygos System
A network of veins that drains blood from the thoracic wall and adjacent structures into the superior vena cava.
Thoracic Duct
Thoracic Duct
The largest lymphatic vessel in the body, transporting lymph from the abdomen and lower limbs to the left subclavian vein.
Sympathetic Chain
Sympathetic Chain
A series of interconnected ganglia that run alongside the vertebral column, part of the autonomic nervous system.
Descending Thoracic Aorta
Descending Thoracic Aorta
Signup and view all the flashcards
Costocervical Trunk
Costocervical Trunk
Signup and view all the flashcards
Intercostal Vessels (Posterior)
Intercostal Vessels (Posterior)
Signup and view all the flashcards
Esophagus
Esophagus
Signup and view all the flashcards
Pericardium
Pericardium
Signup and view all the flashcards
Intercostal arteries
Intercostal arteries
Signup and view all the flashcards
Posterior intercostal arteries
Posterior intercostal arteries
Signup and view all the flashcards
Adamkiewicz artery
Adamkiewicz artery
Signup and view all the flashcards
Bronchial arteries
Bronchial arteries
Signup and view all the flashcards
Thoracic aortic aneurysm
Thoracic aortic aneurysm
Signup and view all the flashcards
Dysphagia
Dysphagia
Signup and view all the flashcards
Endovascular stent graft
Endovascular stent graft
Signup and view all the flashcards
Abdominal aortic aneurysm (AAA)
Abdominal aortic aneurysm (AAA)
Signup and view all the flashcards
Study Notes
Practical 5: Posterior Mediastinum & Review
- Azygos System of Veins: Identify and describe the azygos system of veins.
- Thoracic Duct: Identify and describe the anatomy and course of the thoracic duct.
- Sympathetic Chain: Identify and describe the sympathetic chain.
Posterior Mediastinum
- Contents: The descending thoracic aorta, azygos & hemiazygos veins, thoracic duct, esophagus, sympathetic trunk, and posterior intercostal vessels. Vagus nerves are also listed.
- Location: Posterior to the middle mediastinum. Located between the superior and inferior mediastinum.
- Structures: Aorta, pleural membranes, and pericardial membranes are noted. Medial aspect of the left mediastinum is labeled. The medial aspect of the right mediastinum is also labeled. Specific structures of the anterior and posterior aspects of the mediastinum are labeled
Descending Thoracic Aorta
- Location: Posterior to the root of the left lung and esophagus. Descends towards the midline, then passes through the aortic hiatus of the diaphragm.
- Course: Runs from T4 to T12.
- Branches: Costocervical trunk from subclavian artery. Posterior intercostal and subcostal arteries. Bronchial arteries are present and unpaired branches are present anteriorly including esophageal, mediastinal, and pericardial branches. Superior phrenic arteries are paired branches.
Thoracic Aortic Aneurysms & Aortic Dissection
- Aortic root & ascending aorta: Aneurysms (60% of thoracic aneurysms) comprise a substantial proportion.
- Aortic arch: Aneurysms are less common (~10%).
- Descending aorta: Aneurysms are less common (~35%).
- Abdominal aortic aneurysms (AAA): significantly more frequent than thoracic aneurysms.
- Risk Factors: Atherosclerosis, hypertension, trauma, and connective tissue disorders (e.g., Marfan's).
Aortic Dissection
- Mechanism: Tear in the tunica intima allows blood into the intima-media space, leading to a rapidly expanding false lumen.
- Presentation: Sudden, tearing chest pain.
Azygos System of Veins
- Variable Arrangement: The arrangement of azygos system veins is highly variable.
- Connections: The azygos system connects thoracic, abdominal, and back veins, crucial for alternate drainage if the SVC or IVC is obstructed.
- Accessory Hemiazygos and Hemiazygous Veins: Cross over vertebrae at T7 and T9 to join the azygos vein.
- Inferior Connections: Connect to lumbar veins and IVC.
Thoracic Duct
- Drainage: Lymph from the right side of the thorax, upper extremities, head, and neck drains into the right lymphatic duct. The rest of the body drains into the thoracic duct.
- Chyle: Fat and lymph from the intestine passes into the cisterna chyli (a dilated sac at L1 level). The cisterna chyli then drains into the thoracic duct.
Chylothorax
- Causes: Thoracic duct injury (e.g., malignancy, infection, trauma).
- Consequences: Chyle leaks into the pleural cavity, potentially leading to lung compression, hypovolemia, and immunosuppression.
- Management: Managed conservatively, or surgically ligated in severe cases. Collateral channels or other venous connections could be used.
Other Pleural Masses
- Haemothorax: Presence of blood in the pleural cavity.
- Pyothorax/Empyema: Presence of pus in pleural cavity.
- Serothorax: Fluid in the pleural cavity, containing fibrin and proteins.
- Hydrothorax: Pleural fluid with low fibrin content.
- Enterothorax: Abdominal organs presenting in thoracic cavity
- Fibrothorax: Fibrosis as a response to pleural inflammation.
- Oleothorax: Presence of oil (historical treatment for TB).
- Urinothorax: Presence of urine in the pleural cavity
- Faecothorax: Presence of faeces in the pleural cavity.
Oesophagus
- Course: Posterior to the trachea, pericardium, and left atrium, then deviates to the left. This path changes as it descends.
- Oesophageal Plexus: Formed by vagus nerve (parasympathetic, visceral sensory) and nerves from the sympathetic trunk (sympathetic).
- Hiatus: Passes through the oesophageal hiatus (level T10).
Dysphagia
- Investigation: Diagnosed via fluoroscopy and barium swallow.
- Diagnosis: Tumours, Ulcers, Extrinsic compression, oesophageal webs, diverticula, motility disorders, and hiatal hernias can all cause difficulty swallowing
- Clinical Relevance: Barium swallows show constrictions from proximity of other structures like the aortic arch & the L main bronchus which contribute to dysphagia.
Tracheoesophageal Fistula & Oesophageal Atresia
- Septum Formation Failure: Abnormal septum development can lead to fistula (abnormal connections) or atresia (abnormally closed passage).
- Tracheo-oesophageal fistula: An abnormal connection between the trachea and the esophagus.
- Oesophageal atresia: The esophagus does not form properly and ends in a closed pouch
- Incidence: Malformations are fatal without early surgical intervention.
Sympathetic Chain
- Origin & Distribution: Originates from spinal nerves T1-L2. Crucial for innervating tissues at all spinal levels.
- Ganglia: Paravertebral chain of ganglia running parallel to the spinal cord. Sympathetic nerve fibers enter at T1 and L2, and travel up or down the chain before exiting to join other spinal nerves to reach their target.
- White Rami Communicantes: Connect with the chain from T1 to L2 ventral rami.
- Gray Rami Communicantes: Connect the chain with spinal nerves, outside of T1 and L2.
- Ganglion Impar: Most inferior ganglion, fuses with its counterpart in the midline.
Cardiac Referred Pain
- Generalization: Cephalic and thoracic splanchnics synapse in paravertebral chain ganglia. Abdominal and pelvic splanchnics synapse in prevertebral ganglia.
- Pain Pathways: Pain signals from the heart travel with sympathetic nerves, and so are referred to dermatomes T1-T4/5.
Lower Thoracic Splanchnic Nerves
- Origin: These nerves branch from the posterior mediastinum.
- Pathway: They travel into the abdomen, supplying related structures.
Horner's Syndrome
- Cause: Compression of the upper thoracic (T1) sympathetic chain (e.g., by a Pancoast tumour).
- Symptoms: Ptosis (drooping eyelid), miosis (constricted pupil), anhidrosis (lack of sweating).
Studying That Suits You
Use AI to generate personalized quizzes and flashcards to suit your learning preferences.
Related Documents
Description
This quiz covers the anatomy of the posterior mediastinum, including the azygos system of veins, thoracic duct, and sympathetic chain. You will identify and describe key structures and their locations within the thoracic cavity. Perfect for students studying human anatomy and thoracic structures.
