postmediastinal

post·me·di·as·ti·nal

(pōst'mē-dē-as'ti-năl, -mē'dē-ă-stī'năl), 1. Posterior to the mediastinum. 2. Relating to the posterior mediastinum.

postmediastinal

(pōst″mē-dē-ăs′tĭ-năl) [″ + mediastinum, in the middle] Behind the mediastinum.