Function of external intercostal -

Ans. is 'a' i.e., Elevation of ribs Actions of intercostal muscleso The main action of the intercostal muscles is to prevent intercostal spaces being drawn in during inspiration and bulging outwards during expiration.o The external intercostals, interchondral portions of the internal intercostals and the levator costae may elevate the ribs during inspiration.o The internal intercostals except for the interchondral portions and the transversus thoracis may depress the ribs or cartilages during expiration.