A brief post with lots of pictures and videos on two conditions that may cause less than five fingers. As I have previously written, there are 5 common causes. Parents have given permission.
Diagnosis 1. Symbrachydactyly. This patient has a great thumb and nubbins past the metacarpals. However function is excellent. The child will likely favor the normal opposite extremity.
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| Symbrachydactyly with great thumb |
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| Palm view of symbrachydactyly with great thumb |
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| Effective grasp in patient with symbrachydactyly |
Diagnosis 2. Cleft hand. This patient has severe cleft hand (and cleft feet) but functions amazingly well. Both hands are the same.
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| Bilateral severe cleft hand, single digit |
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| Cleft hand patient demonstrating function |
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| Radiograph of severe cleft hand, single digit. |
These videos are excellent in showing function. The first video shows finger motion and the second shows writing without aids. The others show the benefits of adaptive devices.
Saturday, October 31, 2020
2 Common Types of an Uncommon Condition- Symbrachydactyly
When I consider all of the different patients with a birth anomalies that I have the privilege to evaluate and treat, there is no question that symbrachydactyly is the diagnosis most often misnamed or unnamed. Amniotic constriction band is perhaps most commonly given as the incorrect diagnosis for the patients.
Symbrachydactyly literally means short, webbed fingers. And that certainly can be how patients with symbrachydactyly present as I have previously shared here- Previous Post. While there are 7 types (depending on your favorite classification), in my mind there are two types which are most common. All seven seem to be related to the same issue, and not a genetic one. We believe that a lack of blood supply to the developing limb is most likely the cause of symbrachydactyly and the timing determines the severity, the type.
The short finger type of symbrachydactyly is really the type that best fits with the name. The fingers are shortened due to a short or absent middle phalanx and the fingers are also commonly webbed. The other common type is the “cleft” type symbrachydactyly in which the thumb and little finger are normal or close to normal and the index, middle, and ring fingers are notably short and may be only a nubbin.
Here are two great examples of these two types of symbrachydactyly. First, the short finger type. This patient had surgery to separate the fingers at about 18 months of age and is functioning at a high level and is satisfied with appearance.
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| Short finger symbrachydactyly. Note the middle phalanx is abnormal. |
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| Short finger symbrachydactyly. Close examination shows the surgical scars from web deepening. |
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| Short finger symbrachydactyly. |
The other common type of symbrachydactyly is the cleft type. The painted fingernails help visualization. And the nubbins are small bones (distal phalanx) with nails that develop from the ectoderm after the vascular insult affects the mesoderm in the developing arm.
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| Cleft type symbrachydactyly. Note the three nubbins in the cleft. |
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| Cleft type symbrachydactyly. Note the thumb is normal and the little finger is more, but not normally developed as the middle phalanx is absent. |
Thanks for reading,
email: congenitalhand@wustl.edu
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This is interesting to know that I'm not the only person who has missing digits. I'm 52 and was born with three fingers on each hand as well as webbed. I too was a patient at Shriners Hospital in Greenville, SC. Thank you for sharing the article.
Can congenital finger and toe deformities be caused by illegal drug abuse by the expectant mother?
Thank you for the question. Most birth differences are genetic (either a known family history or a new genetic issue). Our advancing ability to identify genetic problems will continue to help our understanding.
There are certainly environmental risk factors and these include alcohol, smoking, and other drug use.