CONGENITAL HAND DIFFERENCES

Congenital Hand Differences
What are congenital hand
differences?

Babies born with hands that are different than
the normal hand have a congenital hand
difference.



What causes
congenital hand differences?

The upper limb is formed between four and eight
weeks after the sperm and egg unite to form an
embryo. The embryo develops an arm bud at four
weeks. The tip of the arm bud sends messages to
each cell as the upper limb forms. Millions of
steps are followed to form a normal arm. Failure
of any of these steps to occur can result in a
congenital hand difference. Research continues
into further understanding of this embryonic
process. Some congenital hand differences may
occur due to a genetic cause. Many congenital
hand differences just occur without an apparent
cause.
What are different types of
congenital hand differences?

One in twenty children is born with some
difference from normal, either major or minor.
The different groups of congenital hand
differences include missing parts of the arm
(failure of formation), webbed or fused parts of
the hand (failures of separation), extra parts
present in the hand (duplication), undergrowth
or overgrowth of parts of the hand, or
constriction band syndrome.
What are common congenital
hand differences?

The most common congenital hand difference in
the Caucasian population is webbed fingers (syndactyly
- see Figure 1).
The most common congenital hand difference in
the black population is an extra, sixth digit on
the little finger side (post-axial polydactyly -
see Figure 2). The
most common congenital hand difference in the
Asian population is an extra thumb (thumb
polydactyly - see
Figure 3).
Which congenital hand
difference does my child have?

Because there are so many different congenital
hand differences, it is important that your
child be evaluated by a hand surgery specialist
to help determine if any treatment is needed.
Some congenital hand differences are associated
with genetic disorders or other medical
problems. Your hand specialist may request
further genetic evaluation by a geneticist, or
may request further medical testing by your
pediatrician or family physician.
How do parents feel if their
child has congenital hand differences?

Immediately after the birth of a child with a a
congenital abnormality, the patents may feel
shock, anger and guilt. These are normal
emotions. All the dreams of a perfect baby did
not take place. Each family member must cope
with their feelings. Rarely is there anything
parents or doctors could have done differently.
Your newborn doesn’t realize that he or she
is different. The baby has all the normal needs
of any newborn. The way the baby has formed is
normal for him or her, without pain and without
a sense of loss. Talk to your physician about
support groups or professional help.
Can congenital hand
differences be treated?

All babies born with congenital hand differences
should be evaluated by a hand specialist to make
an individual assessment of the type. Depending
on the type of congenital hand difference,
treatment may be recommended. For example,
webbed fingers are surgically separated. Extra
digits can be surgically removed with
reconstruction of the remaining digit if
necessary. Hand function can be improved if the
functions of thumb pinch or finger grasp is
compromised. Some congenital hand differences
may need therapy to help improve hand

function. In some cases, no intervention is
necessary.

Figure 1:  Syndactyly between long
and ring fingers



















Figure 2:  Polydactyly, with an
extra little finger

Figure 3:  Thumb polydactyly,
with duplication of the thumb

© portions 2006
American Society for Surgery of the
Hand and modified altered adapted and
appended by
www.handctr.com May 2009

Useful Links and Resources
LimbDifferences.org
Polands-syndrome.com
Helping Hands Foundation
Failure to Form

AmnioticBandSyndrome.com
Super Hands Network
Congenital Differences from ASSH (PDF)
On the Other Hand
Little Fins Limb Difference Group
Reach (UK)

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