Mediastinoscopy is a surgical procedure to look at the inside of the upper chest between and in front of the lungs (mediastinum).

During a mediastinoscopy, a small cut (incision) is made in the neck just above the breastbone or on the left side of the chest next to the breastbone. Then a thin scope (mediastinoscope) is inserted through the opening. A tissue sample (biopsy) can be collected through the mediastinoscope and then examined under a microscope for lung problems, such as infection, inflammation, or cancer.