inspiration

(ĭn″spĭr-ā′shŭn )

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[L. in, in, + spirare, to breathe]
Inhalation; drawing air into the lungs; the opposite of expiration. The average rate is 12 to 18 respirations per minute in a normal adult at rest. Inspiration results in the spontaneously breathing person by the actions of the muscles of respiration (see below), or in the mechanically ventilated patient by ventilator pressure.
SEE: diaphragm for illus.; SEE: respiration
Inspiration may be costal or abdominal, the latter being deeper. The muscles involved in forceful inspiration are the external intercostals, diaphragm, levatores costarum, pectoralis minor, scaleni, serratus posterior, superior sternocleidomastoid, and sometimes the platysma.

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