DAANCE Certification Practice Exam

The accessory muscles of respiration play a crucial role in assisting with the breathing process, particularly during situations where the demand for oxygen increases, such as during physical exertion or respiratory distress. The sternocleidomastoid and scalenes are indeed classified as accessory muscles because they facilitate the elevation of the rib cage, thereby expanding the thoracic cavity and aiding in inhalation. The sternocleidomastoid muscle, which runs from the sternum and clavicle to the mastoid process of the skull, helps elevate the sternum when the head is fixed. Similarly, the scalene muscles, found in the lateral neck, aid in elevating the first two ribs during deep breathing. This elevatory action assists the primary respiratory muscles, such as the diaphragm, in increasing the volume of the thoracic cavity and enhancing airflow into the lungs. In contrast, the other options do not include muscles that serve this specific purpose for respiration. The rectus abdominis and triceps, while important in other movements, do not assist in respiration. Similarly, the deltoids and biceps are primarily involved in shoulder and arm movements. The quadriceps and hamstrings contribute to leg movements and are not involved in respiratory mechanics at all. Therefore, the