The body part that connects the arm to the torso is called the shoulder. The shoulder is a highly flexible joint consisting of the humerus (the upper arm bone), the scapula (shoulder blade), and the clavicle (collarbone). This complex structure allows for a wide range of motion in the arm, which is crucial for various activities such as lifting, throwing, and reaching. The shoulder is supported by a group of muscles known as the rotator cuff, which helps stabilize the joint during movements. However, its flexibility also makes it susceptible to injuries and strains.