Static radiological assessment of the wrist for midcarpal instability (i.e., palmar intercalated segmental instability (P.I.S.I.) and dorsal intercalated segmental instability (D.I.S.I.) can be performed using the triangulation method. This method uses three anatomical landmarks observed on the standard lateral x-ray of the wrist. One hundred and twenty-five normal lateral radiographs were measured to determine the normal range for the dorsal limb (DL) to palmar limb (PL) ratio. A two-step process of performing triangulation is described. The first step is nonspecific screening of the radiograph and defines values greater than 1.0 as having a D.I.S.I. deformity and values less than 0.5 as having a P.I.S.I. deformity. The second step is used only for borderline values which takes the position of the wrist into consideration and uses a normagram (reference chart) to match the DL:PL ratio with the radiometacarpal (RM) angle. Results: the average lateral wrist position was 8.4 degrees of extension (-8.4). The average DL:PL ratio was 0.75 +/- 0.09 (range 0.93 – 0.57). Conclusion: Based on this data, we defined D.I.S.I. deformity of the wrist as DL:PL ratios greater than 1.0 and ratios less than 0.5 representing P.I.S.I. deformities. The triangulation method of assessing midcarpal alignment of the carpus is a practical and simple alternative to the traditional static radiological methods of assessing midcarpal instability of the wrist.