The innermost intercostals muscles are a group of small, thin muscles located between the ribs in the thoracic region of the spine. They are responsible for moving the ribs during inhalation and exhalation, and are important for activities such as breathing and singing. The innermost intercostals muscles originate at the inner surface of the ribs and then insert at the outer surface of the ribs.

In terms of function, the innermost intercostals muscles are important for moving the ribs during inhalation and exhalation. This movement is important for activities such as breathing and singing, as it allows the lungs to expand and contract and allows air to flow into and out of the body. The innermost intercostals muscles also play a role in providing stability to the ribcage, which is important for protecting the internal organs and maintaining a proper posture.

They are active whenever we breathe, sing, or perform any other activity that involves movement of the ribs. They are also used when we laugh, cough, or sneeze, as well as when we perform movements that require stability of the ribcage, such as standing on one leg or performing single-leg exercises.

These muscles are important for activities that involve deep breathing, such as running, swimming, or yoga. They are also important for activities that require control of the breath, such as singing or playing a wind instrument, as well as activities that require stability of the ribcage, such as dancing or martial arts.