Definition of Mediastinum. Mediastinum: The area between the lungs. The organs in the mediastinum include the heart and its large veins and arteries, the trachea, the esophagus, the bronchi, and lymph nodes. Search MedTerms:
The Pax Romana ended because the Roman state had ceased to grow. Boundaries had been set for the Empire, and for the first time the army had become a drain on the econom â¦ y of Rome. Till this point the army provided new slaves and riches from conqured countries.
After the Pax Romana, the Roman Empire started to decline. The reasons were political and economic, and they had problems with foreigners.After the guard killed Commudus, they sold power to the highest bidder.fter the Pax Romana, the Roman Empire started to decline. The reasons were political and economic, and they had problems with foreigners. After the guard killed Commudus, they sold power to the highest bidder.