Mediastinoscopy involves making an incision approximately 1 cm above the suprasternal notch of the sternum, or breast bone. Dissection is carried out down to the pretracheal space and down to the carina. A scope (mediastinoscope) is then advanced into the created tunnel which provides a view of the mediastinum. The scope may provide direct visualization or may be attached to a video monitor.
Mediastinoscopy provides access to mediastinal lymph node levels 2, 4, and 7.
Historically, mediastinoscopy has been the gold standard for the staging of lung cancer. However, with advances in minimally invasive procedures and imaging, mediastinoscopy usage has declined significantly. 
^Kaiser LR (2008). Fishman's Pulmonary Diseases and Disorders (4th ed.). McGraw-Hill. p. 1853–1854. ISBN0-07-145739-9.
^Vyas KS, Davenport DL, Ferraris VA, Saha SP. Mediastinoscopy: trends and practice patterns in the United States. South Med J. 2013 Oct;106(10):539-44. doi: 10.1097/SMJ.0000000000000000. PubMed PMID: 24096946. http://www.ncbi.nlm.nih.gov/pubmed/24096946