Sagittal scans demonstrate a dorsally tilted lunate with an increased capitolunate (CL) angle of 58 degrees.

Radioscaphocapitate ligament (RSC)

A coronal T2 fat suppressed scan shows the radioscaphocapitate (RSC) ligament coursing along the volar sulcus of the scaphoid, and blending with the distal band of the palmar scaphotriquetral ligament (this latter one also called "V" ligament because it travels from the scaphoid to the capitate to the triquetrum), forming the arcuate or deltoid ligament http://www.uphs.upenn.edu/ortho/oj/1999/html/oj12sp99p27.html and Resnick and Gilula, Radiology 2003; 226: 171. Proximal to this ligament, and limited by the long radiolunate ligament, lies the space of Poirier. The space of Poirier constitutes an area of ligamentous weakness through which perilunate and lunate dislocations occur.

Notice that in this case the lunate shows a roughly triangular morphology as it slides underneath the deltoid ligament.

Although the palmar radiocarpal ligaments (RSC and RLT) are the most important ligaments for carpal instability, the dorsal radiocarpal ligament (=dorsal radiotriquetral ligament) prevents the development of VISI, whereas the dorsal scaphotriquetral ligament (= dorsal intercarpal) prevents the development of DISI. The dorsal scaphotriquetral ligament inserts to the dorsal ridge of the scaphoid. Gilula. Radiology 2006; 238: 950

Dorsal scaphotriquetral ligament or dorsal intercarpal ligament

In this case, there is an increased SL interval. Therefore, this pattern would correspond to a CID-DISI, or carpal instability dissociative - dorsal intercalated instability. If no fracture is present, and the intrinsic ligaments of the proximal row are intact, the case would fit into the definition of a CIND-DISI, or carpal instability non-dissociative - dorsal intercalated instability.