Spontaneous pneumomediastinum is an uncommon and underdiagnosed disease defined as a nontraumatic presence of free air in the mediastinum.是什么意思_Spontaneous pneumomediastinum is an uncommon and underdiagnosed disease defined as a nontraumatic presence of free air in the mediastinum.在線(xiàn)翻譯_英語(yǔ)_讀音_用法_例句