What is the primary function of the pectoralis major muscle?

The pectoralis major muscle serves multiple functions that are critical for arm movement. It is involved in the adduction of the arm, which means it brings the arm closer to the body, playing an essential role in actions like hugging or raising the arm sideways. Additionally, it assists in flexing the arm at the shoulder, enabling forward movement, such as during a pressing motion.

Moreover, the pectoralis major also allows for the inward rotation of the arm. This rotation helps in various activities, including reaching across the body or when performing actions like throwing.

Because the muscle facilitates all these movements—adduction, flexion, and inward rotation—the correct answer encompasses all these functions as part of the pectoralis major's role in arm movement, confirming that "all of the above" is indeed the comprehensive choice.