Citation, DOI & article data
Several classification systems exist for the lunate morphology 1, 2.
The lunate classification proposed by Viegas et al. is arguably the most relevant 3:
- type I lunate: single distal articular facet for the capitate
- type II lunate: additional distal articular facet medially for the hamate
There is roughly an even prevalence of the two morphology types.
Type I lunates are associated with a higher prevalence of dorsal intercalated segment instability (DISI) deformity in the setting of scaphoid fracture non-union (~75% vs 20%).
Type II lunates are associated with hamatolunate impingement syndrome leading to a higher prevalence of hamatolunate degenerative arthritis 4.
- 1. Taleisnik J. The wrist. Churchill Livingstone. (1985) ISBN:0443081344. Read it at Google Books - Find it at Amazon
- 2. Watson HK, Yasuda M, Guidera PM. Lateral lunate morphology: an x-ray study. J Hand Surg Am. 1996;21 (5): 759-63. doi:10.1016/S0363-5023(96)80188-2 - Pubmed citation
- 3. Viegas SF, Wagner K, Patterson R et-al. Medial (hamate) facet of the lunate. J Hand Surg Am. 1990;15 (4): 564-71. - Pubmed citation
- 4. Cerezal L, Del piñal F, Abascal F et-al. Imaging findings in ulnar-sided wrist impaction syndromes. Radiographics. 22 (1): 105-21. Radiographics (full text) - Pubmed citation
- 5. Malik AM, Schweitzer ME, Culp RW et-al. MR imaging of the type II lunate bone: frequency, extent, and associated findings. AJR. American journal of roentgenology. 173 (2): 335-8. doi:10.2214/ajr.173.2.10430130 - Pubmed