Gilula defined three carpal arcs whuch can be distinguished on the PA radiograph of the wrist.
- The first arc runs along the proximal convex articular surfaces of the first row of carpals
- The second arc along their distal concave articular surfaces.
- The last arc is formed by the proximal contours of the capitate and hamate.
- Gilula Arcs
Discontinuity in the symmetry of these arcs is a sign of carpal instability.