Demonstration of the scapholunate space with radiography.

The importance of radiographic evaluation of the scapholunate space, which should not be wider than 2 mm, has been well established in cases of wrist injury. Unfortunately, the assessment of this space is not accurately determined with routine posteroanterior (PA) radiographs, because the scaphoid and lunate bones often overlap. Moreover, the exact portion of the scapholunate space that should be measured has never been clearly defined. Nine wrists with a scapholunate space no wider than 2 mm and without chondrocalcinosis were studied by means of plain routine views and special projections, transaxial and coronal computed tomographic scans, and dissection to determine the precise orientation and anatomy of this space. A PA radiograph with 10 degrees of tube angulation from the ulna toward the radius best demonstrated the scapholunate space. This space should be measured at the level of the midportion of the flat lateral facet of the scaphoid.