How is it possible to have a negative inspiratory reserve volume?

Pressure vs volume: There is an episode of the Simpsons in which their bodies turn inside out, which is what I would picture happening if one had a negative RV. However, negative inspiratory force (NIF) is a useful tool to assess respiratory muscle strength. Inspiration is an active movement, requiring mainly your diaphragm. In folks with neuromuscular diseases or paralysis, their NIF would be closely monitored.

Inside out lungs: Hi eallen6, to be honest, i have never heard of a "negative" reserve volume. It is defined as the maximum amount of air you can inhale. Since you are obviously still breathing, i have to assume that maybe you mean negative inspiratory pressure? This is the force created when your chest wall expands to "suck in" air. Otherwise, maybe it's a misprint? Hope that helps.