Which movement is being performed when the arm is extended straight out to the side?

When the arm is extended straight out to the side, the movement being performed is shoulder abduction. This refers to the action of moving the arm away from the body's midline in the coronal plane. In this position, the arm moves outward, increasing the angle between the arm and the torso.

Shoulder abduction primarily involves the deltoid muscle and the supraspinatus muscle. When the arm is raised to the side, these muscles contract to lift the arm away from the midline. This action is commonly used in various everyday activities, like reaching out or waving.

Understanding shoulder movements is essential in fields such as rehabilitation and sports therapy, as it allows clinicians to assess and address potential mobility issues or shoulder injuries effectively.