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Congenital Hand Differences



Congenital hand differences are abnormalities present at birth. They occur before birth when an embryo is developing the upper extremity. Congenital hand differences are caused by genetic, environmental, and unknown reasons. A variety of hand conditions may occur. 

A hand surgeon and hand therapist should evaluate all babies born with a hand difference. Some conditions do not need treatment. For others, treatment during the first few years of life allows children to best adapt to their hands. Treatments may include splinting, hand therapy, or surgery. 


Your upper limb (arm) develops before you are born. An embryo develops an arm bud at four weeks. The tip of the arm bud sends genetic signals to cells to direct limb formation. The upper limb is formed when an embryo is between four to eight weeks old in the womb. The arm develops first at the shoulder and progresses to the fingers. The development of a limb is a complex process involving millions of steps guided by genetics, your inherited blueprint for growth. Your upper extremity is composed of many bones that provide structure for your wrist and fingers. The bones are connected with strong ligament tissues. Tendons are strong fibers that attach your muscles to your bones and allow movement. Your hand also contains nerves, blood vessels, and fat. The skin that covers your hand protects it from the environment.


Congenital hand differences are abnormalities present at birth. Congenital hand differences occur when an embryo is developing the upper limb. Some conditions may develop due to genetic problems and passed from generation to generation. Other congenital hand differences develop because of environmental factors or for no known reason.


There are several different types of congenital hand differences. Variances can range from major to minor. Some congenital hand differences are associated with other medical or genetic problems. Congenital hand differences are categorized by type including failure of formation, failure of separation, duplication, undergrowth or overgrowth, and constriction band syndrome. Failure of formation describes upper arms, forearms, wrists, hands, or fingers that do not form completely or at all. Failure of separation includes finger webbing. Finger webbing can involve only the skin or can include the finger bones, extra bones, or fingernails. The two bones that make up the forearm, the ulna and radius can also be joined together. Duplication is another type of congenital hand difference. It most commonly involves an extra thumb or little finger, although duplication of any portion of the hand can occur. Overgrowth or undergrowth causes a section of the hand or arm to be too large or too small. This can affect joint structure and function. Constriction band syndrome causes tight bands of tissue to form around the arm, forearm, wrist or fingers. The constrictions can range from mild to severe. Severe constrictions can result in the loss of a portion of the hand.


A hand specialist should evaluate all babies born with a hand difference. The doctor can diagnose a congenital hand difference by reviewing your child’s medical history and conducting an examination. X-rays will identify the location and position of affected bones. If necessary, your doctor may refer you to a geneticist or specialist for diagnosis and treatment of associated medical conditions.


Treatment for congenital hand differences depends on the type and extent of the condition. Some people may not require any treatment. Splinting and hand therapy may be used to improve hand structure and function. Hand therapists can recommend assistive devices to make everyday activities such as handwriting, grooming tasks, and feeding easier.


Surgery can help severe hand differences. Surgeons are able to separate webbed fingers and remove extra fingers. The hand and fingers can be surgically reconstructed to improve function and appearance. There are many methods that may be used and your hand surgeon will discuss the most appropriate options for your child with you. As this type of surgery is specialized even within the realm of hand surgery, you may be referred to a hand specialist with expertise in congenital hand differences.


Recovery from hand surgery may include splinting and hand therapy. Surgery performed in the first few years of life provides children with the greatest opportunity to adapt to their reconstructed hand. Hand therapy and possibly additional hand surgery may be necessary as a child grows and develops.


There is no way to prevent congenital hand differences that occur during pregnancy. It is important for babies with the condition to receive prompt diagnosis from a hand specialist and receive early treatment, if necessary.



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This information is intended for educational and informational purposes only. It should not be used in place of an individual consultation or examination or replace the advice of your health care professional and should not be relied upon to determine diagnosis or course of treatment.

The iHealthSpot patient education library was written collaboratively by the iHealthSpot editorial team which includes Senior Medical Authors Dr. Mary Car-Blanchard, OTD/OTR/L and Valerie K. Clark, and the following editorial advisors: Steve Meadows, MD, Ernie F. Soto, DDS, Ronald J. Glatzer, MD, Jonathan Rosenberg, MD, Christopher M. Nolte, MD, David Applebaum, MD, Jonathan M. Tarrash, MD, and Paula Soto, RN/BSN. This content complies with the HONcode standard for trustworthy health information. The library commenced development on September 1, 2005 with the latest update/addition on April 13th, 2016. For information on iHealthSpot’s other services including medical website design, visit

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