Radiopaque Extremity Rulers

A radiopaque extremity ruler is a specially marked measurement scale designed to be visible on radiographic (X-ray) or fluoroscopic images. It is placed adjacent to or over the limb or area of interest during imaging so that clinicians and radiologists have a known reference for size — for example, to measure bone length, fracture displacement, or prosthetic planning. These rulers are usually made of acrylic or flexible plastic with embedded radiopaque material or filled graduations. They are safe for contact with skin, resist cleaning agents, and are available in various lengths (e.g. 45 cm, 115 cm) and thicknesses. Some are rigid, others flexible (“bendable”) depending on use (e.g. wrapping around limbs). The markings are typically in millimeters and half-centimeters, with a midline (“0” center) in some designs.