arachnodactyly

[ə-răk′nō-dăktə-lē]
n.
  1. A condition in which the hands and fingers, and often the feet and toes, are abnormally long and slender, characteristic of Marfan syndrome.
The American Heritage® Stedman's Medical Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Published by Houghton Mifflin Company.