A skeletal disorder where the patient has unusually long, thin bones, especially noticeable in the fingers and toes: The extreme length and slenderness of the fingers and toes are seen in arachnodactyly or in certain dysplasias, such as the Marfan syndrome.

The Marfan syndrome is a heritable condition that affects the connective tissue.

The primary purpose of connective tissue is to hold the body together and to provide a framework for growth and development. In the Marfan syndrome, the connective tissue is defective and does not act as it should.

Because connective tissue is found throughout the body, the Marfan syndrome can affect many body systems, including the skeleton, eyes, heart and blood vessels, nervous system, skin, fingers and toes, and the lungs.