Findings

Frontal view of the wrist demonstrates triangular shape of the lunate, which partially overlaps the scaphoid and triquetrum. Lateral view confirms lunate dislocation.

Discussion

• Carpal Dislocations:
  • Perilunate (Mayfield II) – lunate and radius alignment is maintained
  • Midcarpal (Mayfield III) – subluxed lunate and dislocated capitate are mis-aligned with the radius
  • Lunate (Mayfield IV) – all ligaments associated with the lunate are disrupted, lunate is dislocated, capitate is aligned with radius
• Mayfield I is scapholunate dissociation.

Diagram

Scalcione et al. AJR 2014, 203 (3), 541-550

References

• Mayfield JK, Johnson RP, Kilcoyne RK. Carpal dislocations: pathomechanics and progressive perilunar instability. J Hand Surg Am. 1980 May;5(3):226-41. PubMed PMID: 7400560.
• Scalcione LR, Gimber LH, Ho AM, Johnston SS, Sheppard JE, Taljanovic MS. Spectrum of carpal dislocations and fracture-dislocations: imaging and management. AJR Am J Roentgenol. 2014 Sep;203(3):541-50. doi: 10.2214/AJR.13.11680. Review. PubMed PMID: 25148156.