Which muscle allows the shoulder to lift and turn the arm?

The deltoid muscle is fundamentally responsible for the lifting and turning of the arm at the shoulder. It has a triangular shape and covers the shoulder joint, making it crucial for various arm movements. The deltoid is divided into three distinct parts: anterior, lateral, and posterior. Each part plays a role in different aspects of arm movement, such as raising the arm to the front, the side, and the back, respectively.

This muscle is key in abduction (lifting the arm away from the body), flexion (raising the arm forward), and extension of the arm. Its position and function make it indispensable for movements that require a range of motion in the shoulder, allowing it to turn the arm effectively in various directions.

The other options relate to different muscle groups or functions. The gluteus maximus is primarily involved in movements of the hip and leg, the abductors specifically refer to muscles that help in moving a limb away from the midline predominantly in the lower body, and the supinators are involved in turning the palm up or forward which is more related to forearm movements rather than shoulder mechanics. Thus, the deltoid muscle stands out as the primary muscle responsible for enabling the shoulder to lift and turn the arm