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- Discussion:
   - local failure of paraxial mesoderm to segment accounts for fused vertebrae;
   - Unilateral Bar:
         - partial failure of segmentation laterally results in unsegmented bar formation;
         - affected side of vertebra involved fails to grow, & growth of vertebrae on side opposite bar may produce scoliosis;
   - congenital kyphosis:
         - partial failure of segmentation anteriorly results in anterior fusion of vertebral bodies;
         - continued growth of the posterior portions of the partially fused vertebrae result in kyphosis;
   - hemivertebrae:
         - unilateral failure of formation of a sclerotome, failure of medial migration of sclerotomal cells, or failure of differentiation of sclerotomal 
                cells may result in wedge-shaped hemivertebra & scoliosis;

- Associated Conditions:
     - renal anomalies:
            - relatively high incidence of renal anomalies is related to the fact that kidney develops from mesoderm adjacent to Somites;
     - pulmonary dysfunction;
     - cor pulmonale
     - back pain;
     - kyphosis may result in paralysis from stretched spinal cord.