The 5 Finger Hand

The 5 Finger Hand is a rare congenital hand difference which I have written about in this blog once before, HERE..  It is, as it sounds, the presence of 5 fingers, all in the same plane, instead of 4 fingers and a shorter (2 phalanx), palmarly placed thumb.   The challenges of the 5 Finger Hand include
- a lack of a full first web space which is so important for large object grasp
- a finger with its extra length instead of the thumb
- a notable appearance difference

These images show a 5 Finger Hand with a small extra thumb.

The 5 Finger Hand with a small extra thumb

The 5 Finger Hand with a small extra thumb

When I consider the 5 Finger Hand, two other diagnoses come to mind.  First is the mirror hand as I have written about HERE.  This diagnosis is clearly different but the extra finger and the general hand appearance and the surgical strategies for reconstruction all make me consider the two diagnoses in a similar fashion.  And second, the thumb in the plane of the hand.  I have previously shared my thoughts in this blog specifically around ulnar deficiency and the thumb in the plane of the hand/ fingers HERE.  We have also shared our experience in the medical literature HERE.

The treatment for the 5 Finger Hand is surgical reconstruction for functional reasons and also for appearance considerations.  We typically prefer a pollicization for our reconstruction.  Most commonly, when we discuss pollicization- as we have in these Pollicization links, we do so for treatment of radial deficiency and the hypoplastic thumb.  This is clearly a different surgical indication but the surgery itself is quite similar.  In the child demonstrated above with a 5 Finger Hand, we excised the small extra thumb and pollicized the 1st finger.

Charles A. Goldfarb, MD

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congenitalhand@wustl.edu