What it looks like
In Poland anomaly, the hand on the affected side may be noticeably smaller overall, or the fingers — particularly the middle three (index, middle, and ring) — may be shorter or less developed than on the other hand. The difference can be subtle or quite pronounced. Some children have mildly shorter fingers with otherwise normal function; others have more significantly underdeveloped finger bones or a markedly smaller hand.
This presentation is sometimes called symbrachydactyly (short, underdeveloped fingers, sometimes with soft tissue webbing) or brachydactyly (short fingers). It often occurs alongside webbed fingers, though either can appear independently.
Why it happens in Poland anomaly
The same vascular disruption that prevents the pectoral muscle from developing can also impair blood supply to the developing hand on the same side. The degree of hand involvement varies based on how far down the arterial disruption extended and when it occurred. In mild cases, only the chest is affected; in more significant cases, the hand and fingers are also involved.
As with all features of Poland anomaly, hand differences are always on the same side as the chest involvement and never bilateral.
Other causes to be aware of
- Isolated brachydactyly — Short fingers can run in families as an isolated trait, unrelated to Poland anomaly.
- Turner syndrome or other chromosomal conditions — Some genetic conditions affect hand size and finger length; a geneticist can evaluate.
- Amniotic band syndrome — Constriction from amniotic bands can cause digit shortening, usually in an irregular pattern.
When one hand is consistently smaller and the same-side chest also appears different, Poland anomaly should be near the top of the differential.
Function and treatment
Many children with mild hand differences in Poland anomaly adapt well and develop excellent hand function through normal childhood use and development. Hand therapy (occupational therapy) in early childhood can help maximize function and dexterity.
For more significant hand differences, surgical options may be considered by a pediatric hand surgeon — including procedures to lengthen fingers, deepen the web spaces, or improve grip. Each case is individual, and the decision about whether and when to pursue surgery depends on the specific anatomy and the family's goals.
When to see a doctor — and which specialist
If one hand is noticeably smaller or the fingers on one hand are significantly shorter, especially alongside chest asymmetry on the same side, seek an evaluation with a pediatric hand surgeon or pediatric plastic surgeon. Early evaluation — even if surgery is not immediately planned — establishes a baseline and ensures the right specialists are involved as the child grows.
Find experienced providers in our specialist directory.