ABSTRACT
Although respiration is often considered the same as breathing, the latter is actually just part of the former. Externally, breathing is the mechanical process that moves air into and out of the lungs, via either costal (thoracic) and diaphragmatic (abdominal) motion of the chest cavity, which the lungs are held into via a slight vacuum pressure. In costal breathing, the major structure causing the movement of the air is the rib cage, which expands and contracts the lungs within, by flexible joints at both the spinal column and the sternum (chest). In diaphragmatic breathing, the sheet-like muscle of the
diaphragm at the bottom of the chest cavity depresses like a membrane pump, pulling the lungs down and thereby filling them with air. Both forms of breathing usually work in unison, although diaphragmatic breathing is more efficient in filling the lungs.
