Arm length refers to the distance from the shoulder to the tip of the fingers when the arm is fully extended. It can vary significantly among individuals and is influenced by factors such as genetics and overall body size. Measuring arm length can be important in various fields, including sports, medicine, and clothing design. In sports, arm length can affect performance in activities like swimming or basketball, where reach is crucial. In medicine, knowing a patient's arm length can assist in fitting prosthetics or determining appropriate rehabilitation exercises. Understanding arm length helps tailor solutions to individual needs.