Diagnosing Congenital Hand Deformities

Doctors often diagnose hand deformities during a prenatal ultrasound, a test that uses sound waves to create images of an unborn child during pregnancy. NYU Langone doctors also diagnose hand deformities by examining a baby immediately after birth.

A baby’s arms and hands form between the fourth and eighth week of pregnancy. Any disruption of this process can lead to a congenital hand deformity. Sometimes a body part, such as the hand or part of the arm bone, stops developing. Other times, parts of the hand, such as the bones and tissues, fail to separate in the womb, leading to syndactyly.

Most of the time the exact cause is unknown, and so the deformities are not preventable.

Treatment cannot begin before a baby is born, but an early diagnosis allows parents to prepare for it after the baby’s arrival. Our doctors offer prenatal consultations, during which they help you and your family plan for treatment. Treatment usually begins in the early years of life.

Physical Examination

To evaluate a hand deformity, an orthopaedist assesses the shape and position of the infant’s hand during a physical examination. He or she evaluates the mobility and stability of the fingers, wrist, and forearm and identifies how well each part works.

The opposite hand, legs, and spine are often examined for any associated deformities. Some hand deformities are related to abnormalities of internal organs, so a pediatric specialist might be needed for further examination.


An X-ray, which uses electromagnetic radiation to create images of bones and organs, can tell a doctor if any bones in the hand or arm are missing, if the bones are short or there are too many of them, and if they are fused.

X-rays of the opposite hand are often taken for comparison. Imaging of the legs and spine may be necessary in conditions where associated abnormalities are common.

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