Final answer:
The serratus posterior superior and external intercostal muscles work together to elevate the ribs during respiration, aiding in the inspiration of air. The diaphragm also contracts to further increase thoracic volume.
Step-by-step explanation:
The muscles that elevate the ribs in respiration are the serratus posterior superior and external intercostals. The external intercostal muscles span the space between the ribs and when they contract, they raise the rib cage, increasing its volume to allow air to flow into the lungs during inspiration. The serratus posterior superior also acts to assist in elevating the ribs. It's important to note that the diaphragm also plays a key role in respiration. When the diaphragm contracts, it flattens and increases the volume inside the thoracic cavity, decreasing pressure and causing air to be drawn into the lungs.