Missing digits Ulnar Deficiency

Hand Limitations in Ulnar Longitudinal Deficiency

My mentor, Paul Manske, clarified years ago that the hand is often the greatest limitation for children with ulnar longitudinal deficiency in this classic ARTICLE.  And, as I have previous blogged HERE, the hand limitations can manifest in many different ways.  There are many different ways this presents in ulnar longitudinal deficiency including: thumb and index finger webspace tightness, syndactyly, absent digits, as well as other findings.  And as noted in previous posts, there may be surgeries which can help the function of the hand affected by ulnar longitudinal deficiency by addressing these limitations.   If surgery is considered in ulnar longitudinal deficiency, the goals of this surgery must be clear and obtainable.

But, many times, function is just fine in ulnar longitudinal deficiency without thinking about a surgery.  Kids with one normal hand can do almost all of life’s activities and if the other hand has at least one digit, function is certainly improved.  Here is one child with ulnar longitudinal deficiency and really, really good overall function.  Like many parents, early in the patient’s life, surgery was of interest.  But, as the patient has grown and her excellent abilities have become clear, surgery is becoming of less interest.  She has great elbow, forearm, and wrist motion.  The index finger is a bit stiff but functional.  The thumb does not really help functionally.  If surgery were to ever be considered, making the thumb a bit stiff might provide a functional improvement.

A patient with ulnar longitudinal deficiency and one good finger.

A patient with ulnar longitudinal deficiency and one good finger.

X-ray of a patient with ulnar longitudinal deficiency and one good finger.

Charles A. Goldfarb, MD
My Bio at Washington University


  1. Hello , we have a healthy 5 month year old baby girl born with just 2 fingers on her left hand (belived to be index and middle finger) and they are webbed together. Missing thumb, ring and little finger .She has good dexterity in her left hand and growing just fine. Her right hand is completely 'normal'. No other conditions. Having met with our local hand surgeon she advised us to have an x-ray at 9 months old with surgery to follow at 12 months old. Our local surgeon diagnosed this as 2 digit Syndactyly. Babys left wrist is slightly thinner than her right, we are unsure if all carpal bones are present and unsure how many metacarpal bones are present. We will know more post x-ray. Do you know why a child is born with only 2 fingers? what causes this condition or do you have theory on what may have caused this?.
    Many thanks

  2. Mr Brown,
    Thanks for the question. I do believe this is most likely ulnar deficiency and not 'only' a syndactyly. This is likely caused by a cell signaling issue during development and is rarely genetic. Unfortunately, we do not have many answers on why as we are only just starting to understand the signaling and the proteins involved.

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