What it looks like
In Poland anomaly, the ribs on the affected side — typically ribs 2 through 5 — may be underdeveloped, shortened, or partially absent. This creates a visible depression or deformity of the chest wall that goes beyond the missing pectoral muscle. In some cases, there is a soft or movable area of the chest where a firm rib cage would normally be. The chest on the affected side may appear significantly smaller or more concave than the other side.
Rib involvement is less common than chest muscle absence alone. It represents a more significant degree of vascular disruption during embryonic development and is associated with more pronounced chest wall asymmetry.
Why it happens in Poland anomaly
The same arterial disruption that prevents the pectoral muscle from developing can, in more significant cases, also impair development of the cartilaginous and bony ribs on that side. The extent of rib involvement depends on the severity and timing of the vascular disruption. In milder cases, only the muscle is absent; in more significant cases, the ribs and underlying chest wall are also affected.
Is it dangerous?
In most cases of Poland anomaly with rib involvement, breathing and cardiac function are not significantly impaired. The remaining chest wall and the diaphragm compensate, and the lung on the affected side is typically present and functional. Most children with Poland anomaly and rib involvement lead fully active lives without respiratory problems.
In the most severe cases — where a significant portion of the rib cage is absent — there may be paradoxical chest wall movement (the chest wall moving inward during inhalation rather than expanding), which can occasionally cause symptoms. These severe cases are uncommon and are typically identified and monitored by a thoracic surgeon alongside the plastic surgery team.
Other conditions to consider
- Pectus excavatum or carinatum — These affect the sternum and central chest wall, typically on both sides, and do not involve muscle absence.
- Scoliosis with rib deformity — Severe spinal curvature can cause rib cage deformity, but the pectoral muscles are present and the pattern differs from Poland anomaly.
- Chest wall tumors or prior surgery — Can cause focal chest wall deformity, but these have a different history and presentation.
Treatment
Chest wall reconstruction for Poland anomaly with significant rib involvement is available and may be recommended when there is notable chest wall instability, functional impairment, or significant cosmetic asymmetry. Options include rib grafts, synthetic or biologic mesh, and custom-fabricated implants shaped to the individual's chest. This is specialized surgery performed at major children's hospitals with chest wall reconstruction programs.
For children with mild rib hypoplasia and no functional symptoms, monitoring during growth is often the initial approach, with reconstruction considered once the chest has matured.
When to see a doctor — and which specialist
If your child has noticeable chest wall depression, asymmetry, or a soft/movable area of the chest on one side, seek evaluation with a pediatric plastic surgeon or pediatric thoracic surgeon at a children's hospital. Both may be involved in evaluation and treatment planning when rib involvement is significant.
Find experienced providers in our specialist directory.