As inspiratory muscles contract, the diaphragm moves inferiorly. simultaneously, what other event occurs?

As the inspiratory muscles contract, the diaphragm moves inferiorly, simultaneously; The other events that occurs are; Volumes of the thorax and lungs increase, which decreases pressure and draws air into the lungs
This is the process of exhalation where when one breathes in, or inhale, the diaphragm contracts and moves downward, which increases the space in the chest cavity, into which the lungs expand. The intercostal muscles between the ribs also help enlarge the chest cavity. They contract to pull the rib cage both upward and outward when one inhales. 

This is the most closely resembles the model.