Apana vayu governs the lower abdominal and pelvic region within the torso from the navel to the pelvic floor. By tuning into the pattern of apana vayu, the investigative yogi gains full knowledge of the intricacies of exhaling, including utilizing the full extent of subtle breathing muscles within the abdomen, pelvis, and pelvic floor.
Prana Vayu governs the region of the chest cavity from the diaphragm to the collarbones and includes the lungs, rib cage, and entire upper torso. The skillful yogi learns to recognize the upward expansive prana vayu pattern and thus gains mastery over the intage of prana into her body.
In this video I discuss the vayu patterns of apana and prana vayu and how the diaphragm is a guide we track when exhaling and inhaling throughly. On my video series A Guide to Ujjayi Breathing I have two important exercises, Apana and Prana, which instruct the student how to track and tune into their breath more thoroughly.