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Etymology: L, expirare, to breathe out
a forced exhalation using the abdominal wall, internal intercostal muscles, and diaphragm.
Expiration accomplished as a result of muscular activity, as in forced respiration. The muscles used in forced expiration are those of the abdominal wall (external and internal oblique, rectus, and transversus abdominis), the internal intercostalis, serratus posterior inferior, platysma, and quadratus lumborum.
See also: expiration