The deltoid muscle is the main muscle responsible for the lifting of the arm and is located at the shoulder. It is a large, triangular muscle that covers the shoulder joint and contributes significantly to the arm's range of motion. The deltoid is divided into three distinct parts: the anterior (front), lateral (middle), and posterior (back) fibers, each contributing to different movements of the shoulder.
When lifting the arm, particularly in lateral abduction (raising the arm to the side), the deltoid's mid-region plays a crucial role. The muscle's structure allows it to provide the strength needed for various positions of the arm, including lifting, reaching, and overhead movements. This makes it an essential muscle for many daily activities and athletic performances.
The serratus anterior primarily functions to stabilize the scapula and assist in upward rotation, but it does not significantly aid in lifting the arm. The latissimus dorsi is involved in movements such as pulling the arms downwards and backward, while the pectoralis major is critical for movements like pushing and adduction of the arm across the body. Therefore, while these other muscles are important for different functions, the deltoid is the primary muscle involved specifically in lifting the arm at