Movie 2.

Lung ventilation with a blood pressure cuff applied to the saccular region in boa03. A blood pressure cuff is applied around the saccular portion of the lung and ribs in the posterior region (gold) do not rotate (middle graph). Ribs in the anterior vascular region (teal) rotate substantially (upper graph). Airflow is recorded with pneumotachography (bottom graph) and airflow into the vascular region is visible as the ribs expand, as air shows white within the darker, more radio dense body of the snake.