Return to the superior mediastinum. (G 3.60B;N 203;Gl 10.6B)
- Look for some fatty tissue immediately posterior to the manubium of the sternum. This is most likely the remnant of the thymus. Identify the right and left brachiocephalic veins. Look for the left superior intercostal vein draining into the left brachiocephalic vein. Identify the origins of the brachiocephalic, left common carotid and left subclavian arteries. Identify the right vagus nerve. (G 3.61;N 227;Gl 9.3A) The right vagus nerve passes anterior to the subclavian artery and then posterior to the right main bronchus. Attempt to identify the sympathetic cervical cardiac nerves contributing to the cardiac and pulmonary plexuses.
- Identify the trachea and esophagus. Trace the trachea to its bifurcation into the right and left main bronchi. Identify the superior and inferior tracheobronchial lymph nodes at the bifurcation. (G 3.63;N 205;Gl 9.31A) Attempt to identify one or more bronchial arteries. (G 3.63;N 239;Gl 10.25) Examine the cut (from the removal of the lung) edge of the bronchus. Identify the small lumen of a vessel. This is a bronchial artery. Attempt to trace it back to its origin from the aorta (or posterior intercostal artery).
Important Relationships
- The esophagus is positioned posterior to the trachea.
- The esophagus passes posterior to the left main bronchus.
- The descending (thoracic) aorta passes posterior to the left main bronchus.
- At the hilum of the left lung, the pulmonary artery is positioned superior to the main bronchus.
- At the hilum of the left lung, the pulmonary veins are positioned anterior and inferior to the main bronchus.
- At the hilum of the right lung, the pulmonary artery is positioned anterior to the main bronchus.
- At the hilum of the right lung, the pulmonary veins are positioned anterior and inferior to the main bronchus.
- At the hilum of the right lung, the pulmonary veins are positioned anterior and inferior to the pulmonary arteries.
