Which statement best describes the intercostal muscles?

The intercostal muscles play a crucial role in the respiratory process by aiding in the expansion and contraction of the ribcage. During inhalation, the external intercostal muscles contract, lifting the ribcage and allowing the lungs to expand as air is drawn in. Conversely, during exhalation, the internal intercostal muscles can contract to help push air out of the lungs by drawing the ribcage downward and inward. This functional duo of muscles is vital for efficient breathing and ensures that the lungs can effectively fill with air and expel carbon dioxide.

The other statements are less accurate in describing the primary function of the intercostal muscles. While the intercostal muscles are indeed located near the spine and ribs, they do not primarily assist in spinal bending or shoulder movement, and they do not connect abdominal muscles to the thoracic region directly. Their main role is firmly established in the mechanics of respiration rather than in movements associated with spinal or shoulder flexibility.