: belonging only to the person or group specified. 1  She has the sole authority to hire new staff members. [=only she can hire new staff members] 2  He has sole jurisdiction of the area.
Dr. Stern responded: Dead space in lung. Dead space is a term used to describe an area of the lung where gas exchange cannot occur - it does not mean dead lung tissue. Everyone has dead space and it is comprised mainly of your airways. It is measured as a percentage. Dead space is affected by many variables including the size of the breath we inhale.
The intercostal muscles between the ribs also relax to reduce the space in the chest cavity. As the space in the chest cavity gets smaller, air rich in carbon dioxide is forced out of your lungs and windpipe, and then out of your nose or mouth. Breathing out requires no effort from your body unless you have a lung disease or are doing physical activity. When you're physically active, your abdominal muscles contract and push your diaphragm against your lungs even more than usual. This rapidly pushes air out of your lungs.