Following x ray wrist lateral view shows:
Ref. Grainger and Allison's Diagnostic Radiology. Page. 502
 
Perilunate dislocation (X ray)

AP radiograph 
	
Dislocation is often overlooked
Disruption of the normally smooth line made by tracing the proximal articular surfaces of the hamate and capitate
Increased overlap of lunate and capitate


Lateral radiograph
	
Dislocation more easily appreciable
Capitate not sitting within the distal articular 'cup' of the lunate
Line drawn through radius and lunate fails to intersect capitate 
Lunate remains in articulation with distal radius (as opposed to lunate dislocation where it is usually in a volar position)
Abnormal scapholunate angle (normal 30-60 degrees, reduced in dorsal perilunate dislocation)


Abnormal capitolunate angle (normal 0-30 degrees, increased in dorsal perilunate dislocation)
Lunate dislocation
Perilunate dislocation
DISI
VISI