Deltoid

The deltoid is a triangular shoulder muscle that covers the joint where your arm connects to your body. Its main function is to facilitate shoulder movements such as lifting your arm to the side (abduction), raising it forward (flexion), or moving it backward (extension). The deltoid is essential for a wide range of activities like lifting, pushing, and reaching. It also helps stabilize the shoulder joint, providing strength and mobility. This muscle has three parts—anterior, lateral, and posterior fibers—each contributing to different movements, working together to enable smooth and controlled shoulder motion.