Term
| Describe the divisions of the mediastinum |
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Definition
| The mediastinum is divided into superior and inferior divisions – the inferior is composed of anterior, middle (heart), and posterior. |
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Term
| Where does the superior and inferior mediastinum meet |
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Definition
| The line between the superior and inferior mediastinum is the transverse thoracic plane, transecting the sternal angle, right below the arch of the aorta. This is the location where the trachea splits into two primary bronchi. The TTP also passes in between T4 and T5 |
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Term
| What organs are included in the superior mediastinum |
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Definition
| The superior mediastinum includes the thymus gland, brachiocephalic veins, SVC, aortic arch, roots of the aortic arch, the trachea and esophagus |
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Term
| What organs and nerves are contained by the inferior mediastinum |
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Definition
| The inferior mediastinum contains the vagus and phrenic nerves, the cardiac plexus of nerves, the left recurrent laryngeal nerve, and the trachea / esophagus / thoracic duct |
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Term
| Where does the left vagus nerve give off the left recurrent laryngeal nerve? The right? |
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Definition
| The vagus gives off the left recurrant laryngeal at the arch of the aorta. The right is given off at the right subclavian |
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Term
| Where is the posterior mediastinum located |
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Definition
| The posterior mediastinum is located inferior to the TTP, anterior to T5-T12. Some organs cross the superior mediastinum to reach the posterior mediastinum |
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Term
| What structures are found in the posterior mediastinum |
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Definition
| Thoracic aorta and duct, azygos and hemiazygos veins, esophagus and its nerves, the thoracic sympathetic trunk and splanchnic nerves. |
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Term
| Where does the esophagus, aorta, and IVC enter the abdomen? |
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Definition
| The esophagus enters the abdomen at T10, the aorta at T12, and the IVC at T8 |
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Term
| Where does the esophagus narrow in the thorax, and what is the clinical significance? |
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Definition
| At the distal pharynx, the aortic arch (right side), the left mainstem bronchus, and the diaphragm. These are common “difficulty swallowing” sites |
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Term
| Where do the left and right vagus nerves appear in the abdominal esophagus |
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Definition
| The left vagus nerve moves anteriorly and the right vagus nerve moves posteriorly into the esophageal plexus. |
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Term
| What spinal cord segments does the phrenic nerve arise from |
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Definition
| C3, C4, C5 (keeps the diaphragm alive) |
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Term
| Describe the relative locations of the vagus and phrenic nerves |
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Definition
| The vagus nerve travels behind the root of the lungs, while the phrenic nerve travels in front of the root of the lungs |
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Term
| Where is the descending aorta in relationship to the esophagus |
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Definition
| The descending aorta is left and posterior to the esophagus |
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Term
| Where is the esophagus in relationship to the primary bronchi |
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Definition
| The esophagus is behind the left bronchus, next to the right |
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Term
| Describe the thoracic duct traveling up the vertebral column |
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Definition
| The thoracic duct crosses from right to left of the esophagus at T7 / T6 |
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Term
| Where does the thoracic duct originate |
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Definition
| The thoracic duct originates in the cicternae chylae on the right side of the vertebral column. |
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Term
| What is the difference between splanchnic and sympathetic chain fibers |
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Definition
| Splanchnic nerves don’t synapse in the sympathetic chain, they are all preganglionic |
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Term
| Describe the splanchnic nerves (locations of cell bodies, locations of exit from the sympathetic trunk, names of the nerves) |
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Definition
| The cell bodies of splanchnic nerves are located in the posteriolateral horn (T1-L2). They leave the sympathetic trunk at T5 through T12. The greater, lesser, and least splanchnic nerves are the names of them (from medial to lateral) |
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Term
| What is the clinical significance of IVC obstruction in regards to the azygos system |
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Definition
| The IVC does not drain any of the thoracic cavity, so obstruction of it does not harm the lungs or other thoracic viscera. |
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Term
| What is the origin, course, and termination of the thoracic duct |
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Definition
| The thoracic duct originates in the cisterna chlyi in the lumbar region, traveling up the vertebral column on the right side until T6 / T7 where it moves to the left side, curling around in an arch over the root of the lung and dumping into the left subclavian vein. |
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Term
| In a transverse scan, if you see two bronchii, where are you in relationship with the arch of the azygos |
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Definition
| If you see two bronchae, you are too low to see the arch of the azygos |
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