Diaphragm Descent 1-2 cm Quiet — FRCA Primary MCQ

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ModeratePhysiology - RespiratoryDiaphragm Descent 1-2 cm QuietFRCA Primary

Regarding the mechanics of breathing during quiet inspiration the diaphragm descends approximately:

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Correct answer: A — 1-2 cm

During quiet tidal breathing the diaphragm descends approximately 1-2 cm. During deep inspiration it can descend up to 10 cm. The diaphragm accounts for approximately 75% of the tidal volume during quiet breathing. The external intercostals contribute the remaining 25% by elevating and expanding the ribcage.

Reference: Power Kam 2018 Principles of Physiology for the Anaesthetist