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


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 may include:

Note: Having long, slender fingers may be normal.

When to Contact a Medical Professional

Some children are born with arachnodactyly. It may become more noticeable over time. Talk to your health care provider during a routine exam 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 and ask questions about the person's medical history, including:

  • 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.

Alternative Names

Dolichostenomelia (refers to a long, slender body, not just fingers); Spider fingers; Achromacria


Doyle Al, Doyle JJ, Dietz HC. Marfan syndrome. In: Kliegman RM, Stanton BF, St Geme JW, Schor NF, eds. Nelson Textbook of Pediatrics. 20th ed. Philadelphia, PA: Elsevier; 2016:chap 702.

Herring JA. Orthopaedic-related syndromes. In: Herring JA, ed. Tachdjian's Pediatric Orthopaedics. 5th ed. Philadelphia, PA: Elsevier Saunders; 2014:chap 41.

Review Date 11/3/2015

Updated by: Kimberly G. Lee, MD, MSc, IBCLC, Associate Professor of Pediatrics, Division of Neonatology, Medical University of South Carolina, Charleston, SC. Review provided by VeriMed Healthcare Network. Also reviewed by David Zieve, MD, MHA, Isla Ogilvie, PhD, and the A.D.A.M. Editorial team.

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