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.
Pax Romana (Latin for  Roman Peace ) was the long period of relative peace and minimal expansion by the Roman military force experienced by the Roman Empire after the end of the Final War of the Roman Republic and before the beginning of the Crisis of the Third Century.ax Romana (Latin for  Roman Peace ) was the long period of relative peace and minimal expansion by the Roman military force experienced by the Roman Empire after the end of the Final War of the Roman Republic and before the beginning of the Crisis of the Third Century.