Arachnodactyly refers to the elongated, thin "spider like" fingers pathognomic of Marfan's disease 1.

A metacarpal index has been suggested as a radiographic criteria for arachnodactyly. To obtain it, the length of the second, third, fourth and fifth metacarpals is divided by their width at the mid shaft. An index of greater than 8.4 is considered the upper limit of normal 2 .

From the Greek "arachno" refers to spiders and "dactyly" means fingers


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Article information

rID: 66385
Section: Syndromes
Synonyms or Alternate Spellings:
  • achromachia

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