Presentation
Patient in pain after falling due to motorcycle accident with dorsiflexion hand 3 days ago.
Patient Data
Age: 35 years
Gender: Male
From the case:
Perilunate dislocation


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Info

- loss of Gilula arcs
- proximal migration of capitate
- capitate not sitting within the distal articular 'cup' of the lunate
- a 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)
- piece of pie sign: although also seen in lunate dislocation it may prove very helpful in initial identification of lunate related pathology
Case Discussion
Perilunar dislocation must be distinguished from lunate dislocation. The main key to the diagnosis of lunate dislocation is the appearance of the teacup pouring between the lunate and radius, while in the perilunate dislocation it does not.