It's called the pleural cavity. See the related link for more information.
Mediastinum. That is the cavity that contains the heart.
mediastinummediastinumThe mediastinum is the space between the lungs.
The bell jar is an airtight space. When the rubber diaphragram is pulled the volume of the space increases and air rushes into fill it, therefore expanding the balloons. When the diaphragram is released the volume of the space dcreases and the air in the balloons is pushed out. The balloons deflate.
mediastinumintra-thoracic space or mediatstinum
The space above the mercury is airtight, there is no air above the mercury
space between your inner and outer pleura tissues; located in your lungs. It contains a liquid that provides lubrication to keep the inner and outer pleura in sequence during respiration.
this is the thoracic cavity, the space between the neck and the abdomen, this contains the lungs, heart & the main artery called the aorta, the lungs are covered by a membrane called the pleura which holds the lungs in situ and is the area affected by pleurisy, if air or gasses are allowed to permeate this area outside the lungs the vacuum that enables breathing is compromised and a collapsed lung can occur.
Normally, the pressure in the lungs is greater than the pressure in the pleural space surrounding the lungs
An "airtight cage" is a very small inclosed space, in which you are in.
plueral space
I am not sure if you're referring to 'pleural', which refers to the lining between the lungs and the muscles of the thorax. The pleural space is the space around the lungs within the cavity of the thorax and it contains pleural fluid, which helps reduce friction of breathing as well as other things. A person can also have a pleural effusion or pleurisy, which are both conditions affecting that space.
that's easy the lungs