Which muscle in the chest assists with both breathing and arm raising?

The serratus anterior muscle plays a significant role in both breathing and arm movement. It is positioned on the side of the thorax and is involved in the elevation of the ribs during inhalation, assisting with breathing. Moreover, this muscle is crucial for the upward rotation and protraction of the scapula, which facilitates the lifting of the arm above shoulder height. The serratus anterior helps stabilize the scapula against the thoracic wall, enabling movements of the arm in activities such as reaching and pushing. This dual function makes it unique in its contribution to both respiration and upper limb mobility.

On the other hand, while other muscles like the pectoralis major contribute to arm movement, they do not assist in inhalation to the same extent. The trapezius primarily supports shoulder movement and stability, and the rhomboids are mainly involved with scapular retraction, not chest expansion or breathing.