Symphalangism is one type of finger stiffness; I previously written about it here. I wanted to share a few more thoughts. In addition to the classification noted in my other post, I often think of symphalangism in terms of whether or not the fingers are short. Whether the fingers are short or not, symphalangism is quite rare.
Flatt and Wood reported on symphalangism and divided it into 3 types (a long time ago- 1975, in the journal Hand)
– Symphalangism with normal length fingers (i.e. True Symphalangism)
– Symphalangism with short fingers (symbrachydactyly)
– Symphalangism with another syndrome like Aperts
The clinical examination is notable for the lack of motion of one or more of the interphalangeal joints- typically the proximal interphalangeal joint. It can be one finger or it can be many fingers. Importantly, the normal creases of the fingers are not there in symphalangism.
|The arrow is pointing to the top of the PIP joint of the pointer (index) finger. Note the normal creases which demonstrate that the finger has been moving.|
|Symphalangism. This is the child attempting to make a full fist. The PIP joints do not flex (bend) much.|
|The other hand in Symphalangism. This is the child attempting to make a full fist. The PIP joints do not flex (bend) much.
Also note the lack of creases on the tops of the fingers.
|Careful review of the x- rays show that the PIP joints have not developed in symphalangism.|
|Lateral view (side view) of the hand and fingers. The PIP joints have not developed in symphalangism. The arrow marks the PIP joint of the long finger (middle finger).
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