Volume vs Transorgan static pressure

[tartrate]

On FA 2014 pg 597, there is a graph on the upper right. What does this graph mean? It seems like it's saying some magical transorgan static pressure is somehow related to the chest wall and lung. Would it make more sense to say that the x axis is alveolar pressure, and that the signs (negative/positive) should be switched? That way when the chest wall increases in volume (inspiration), we get a negative x value. And why don't the lungs follow the chest wall into the negative x axis range?

Also, what is the significance of the lung-chest curve doing that sly little dip below the lung curve towards the right?

(not the First Aid image, but it is similar)

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[thehundredthone]

The magic lies in the actual connection between the chest wall and the lungs, called the pleura. This topic has been discussed here before, see if one of these threads helps.

http://forums.studentdoctor.net/threads/lung-chest-wall.1067842/
http://forums.studentdoctor.net/threads/nbme-5-respiratory-question.943341/
http://forums.studentdoctor.net/threads/negative-vs-positive-pressure-help.1010221/#post-14141672