Observe the mediastinum Superior Divisions: sup and inf. part mediastinum Anterior Inf part is divided into three parts, mediastinum Ant. mid and post mediastinum 上纵隔 Observe both sides of mediastinum ◆ The middle part is pulmonary root曹 后 纵 anteriorly: phrenic n and pericardia phrenic blood vessels Anteroinferior part: pericardium: Posteriorly: esophagus and vagus Midddle mediastinum nerve Inferior mediastinumDivisions: sup.and inf.part Inf.part is divided into three parts， Ant.mid and post.mediastinum. Observe both sides of mediastinum：  The middle part is pulmonary root anteriorly: phrenic n.and pericardio phrenic blood vessels.  Anteroinferior part: pericardium：  Posteriorly: esophagus and vagus nerve Observe the mediastinum Superior. mediastinum Inferior mediastinum Midddle mediastinum Anterior mediastinum