...David R. Carrier ABSTRACT Although the intercostal muscles play an important role in lung ventilation, observations from fishes and ectothermic tetrapods suggest that their primary function may be locomotion. To provide a broader understanding of the role these muscles play in locomotion, I...

... by two deep hypaxial muscles, the transversalis and the retrahentes costarum. Inspiration is produced by the external and internal intercostal muscles. Although the two intercostal muscles are the main agonists of inspiration, neither is involved in expiration. This conflicts with the widely held notion...