The skeletal alignment accepted as normal; used for evaluating posture. There is equilibrium around the line of gravity and the least amount of stress and strain on supporting muscles, joints, and ligaments. From either the front or the back, a plumb bob would bisect the body equally. From the side, a plumb bob would be anterior to the lateral malleolus and the axis of the knee, posterior to the axis of the hip and the apex of the coronal suture, and through the bodies of the lumbar vertebrae, the tip of the shoulder, the bodies of the cervical vertebrae, and the external auditory meatus.