Final answer:
The layers of muscles between the ribs that raise and lower the rib cage during breathing are called intercostal muscles. There are three sets of intercostal muscles: external intercostal muscles, internal intercostal muscles, and innermost intercostal muscles.
Step-by-step explanation:
The layers of muscles between the ribs that raise and lower the rib cage during breathing are called intercostal muscles. There are three sets of intercostal muscles: external intercostal muscles, internal intercostal muscles, and innermost intercostal muscles.
The external intercostal muscles aid in inspiration by raising the rib cage, while the internal intercostal muscles are used for expiration by drawing the ribs together to constrict the rib cage. The innermost intercostal muscles act as synergists for the internal intercostal muscles.