thoracoscopy

n. pleural endoscopy, visual examination of the chest cavity by means of an endoscope

Thoracoscopy is a medical procedure involving internal inspection of the pleural cavity. It was developed by Hans Christian Jacobaeus, a Swedish internist in 1910 for the treatment of tuberculous intra-thoracic adhesions. He used a cystoscope to examine the thoracic cavity, developing his technique over the next twenty years.
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Thoracoscopy is the insertion of an endoscope, a narrow—diameter tube with a viewing mirror or camera attachment, [more]Thoracoscopy - Community and Resources

The use of a thin, lighted tube (called an endoscope) to examine the inside of the chest.