First mark the site to be measured. This girth measurement is usually taken on the right side of the body. The arm is relaxed and hanging by the side, and the circumference is taken at the level of the mid-point between the acromion (boney point of shoulder) and the olecranon (boney point of elbow) processes. When recording, you need to make sure the tape is not too tight or too loose, is lying flat on the skin, and is horizontal