The navicular fat stripe: a useful roentgen feature for evaluating wrist trauma.

The navicular fat stripe (NFS) is a useful roentgenographic feature for evaluating traumatic wrist injury. A radiolucent stripe, cast by a thin collection of fat paralleling the lateral surface of the navicular bone, was seen in 96 percent of 400 normal wrists examined because of trauma. Obliteration or displacement of this line (positive NFS sign) is commonly present in acute fractures of the naviculum, radial styloid process, and proximal first metacarpus. A ositive NFS sign serves to alert the radiologist that an underlying fracture is likely. In particular, the NFS sign generally accompanies a navicular fracture.