What is the role of external intercostal muscles in inspiration?

What is the role of external intercostal muscles in inspiration?
  1. They contract and lift up the ribs and sternum
  2. They relax and push down the ribs and sternum
  3. They contract and push down the ribs and sternum
  4. They relax and lift up the ribs and sternum

Solution

The contraction of external intercostal muscles lifts up the ribs and the sternum causing an increase in the volume of the thoracic chamber in the dorso-ventral axis.

Asked in: NCERT

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