5/17/2009 case 1

On the first image - there is loss of the Arcs of Gilula and a pie shaped lunate bone. On the lateral view, there is loss of normal alignment between radius and lunate and the lunate with the capitate. This is called the "spilled teacup" sign. Additionally, there is a dorsal (posterior) chip of bone which signifies a fracture of the triquetral bone of the wrist. This is called a transtriquetral lunate fracture-dislocation.

Lunate dislocations - are the most severe and most unstable of the carpal dislocations. There are multiple tears of the carpal ligaments such as the scapholunate ligament, lunocapitate, lunotriquetral and radiolunate ligaments. The most common dislocation is the perilunate dislocation which is where the alignment between the lunate and capitate is disrupted but the radius-lunate alignment is maintained.

reference: http://www.ajronline.org/cgi/reprint/133/3/503.pdf and http://radiographics.rsnajnls.org/cgi/content/full/28/6/1771?maxtoshow=&HITS=10&hits=10&RESULTFORMAT=&fulltext=lunate+dislocation&andorexactfulltext=and&searchid=1&FIRSTINDEX=0&sortspec=relevance&resourcetype=HWCIT