Arachnodactyly ("spider fingers") or achromachia,'s a condition in which the fingers are abnormally long and slender in comparison to the palm of the hand. It can be present at birth or develop in later life. It's also seen in some cases that all or a few fingers can be bent backwards of 180 degrees. Causes This feature can occur on its own, with no underlying health problems. However, it can also be associated with certain medical conditions. Examples include Marfan syndrome and homocystinuria… (More on Arachnodactyly)