1. Chest X-ray revealed right hemithorax opacity.

2. Results. Expansion thoracoplasty of the constricted left hemithorax improved scoliosis but increased left lung volumes only moderately compared with Disease rabbits.

3. A chest x-ray revealed opacity of the left hemithorax suggesting massive pleural effusion.

4. Summary of Background Data. In children with thoracic insufficiency syndrome, expansion thoracoplasty of the constricted hemithorax improves respiratory function and controls scoliosis.

5. Postoperative lung function was better than predicted, attributable to the therapeutic benefit of deflation of the hemithorax.

6. The diagnosis was confirmed on chest X-ray which showed herniation of abdominal organs into the left hemithorax and mediastinal shift to the right.

7. These were compared with Disease rabbits allowed to grow with a constricted left hemithorax and Normal rabbits.