Health Library

Arachnodactyly

Dolichostenomelia; Spider fingers; Achromachia

Arachnodactyly is a condition in which the fingers are long, slender, and curved. They look like the legs of a spider (arachnid).

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Considerations

Long, slender fingers can be normal and not associated with any medical problems. In some cases, however, "spider fingers" can be a sign of an underlying disorder.

Causes

Causes may include:

• Homocystinuria
• Marfan syndrome
• Other rare genetic disorders

When to Contact a Medical Professional

Some children are born with arachnodactyly. It may become more evident over time. Talk to your child's health care provider if your child has long, slender fingers and you are concerned that an underlying condition may exist.

What to Expect at Your Office Visit

The provider will perform a physical exam. You will be asked questions about the medical history. This includes:

• When did you first notice the fingers being shaped like this?
• Is there any family history of early death? Is there any family history of known hereditary disorders?
• What other symptoms are present? Have you noticed any other unusual things?

Diagnostic tests are most often not necessary unless a hereditary disorder is suspected.

References

Doyle JJ, Dietz HC. Marfan syndrome. In: Kliegman RM, St. Geme JW, Blum NJ, et al, eds. Nelson Textbook of Pediatrics. 22nd ed. Philadelphia, PA: Elsevier; 2025:chap 743.

Grahame R, Hakim AJ. Arachnodactyly--a key to diagnosing heritable disorders of connective tissue. Nat Rev Rheumatol. 2013;9(6):358-364. PMID: 23478494 pubmed.ncbi.nlm.nih.gov/23478494/.

Herring JA. Orthopaedic-related syndromes. In: Herring JA, ed. Tachdjian's Pediatric Orthopaedics. 6th ed. Philadelphia, PA: Elsevier; 2022:chap 37.

Review Date: 10/3/2025  

Reviewed By: Mary Terrell, MD, NABBLM-C, IBCLC, Neonatologist, Cape Fear Valley Medical Center, Fayetteville, NC. Review provided by VeriMed Healthcare Network. Also reviewed by David C. Dugdale, MD, Medical Director, Brenda Conaway, Editorial Director, and the A.D.A.M. Editorial team.

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