Malformations and anomalies

Vertebral column
It is usual for 24 vertebrae to be formed: 7 cervical, 12 thoracic and 5 lumbar vertebrae. However, the actual number of vertebrae can vary from 23 to 25. These variations mostly occur at the junction between the lumbar and the sacral column. The last lumbar vertebra may be incorporated into the sacrum (sacralization). Conversely, the first sacral vertebra may remain free (lumbarization).
In scoliosis, the vertebral column deviates laterally. The congenital form of scoliosis is due to half and wedge-shaped vertebrae. Locally, the segmentation into vertebrae may fail on one side which may lead to a bending of the column.
Klippel-Feil syndrome is the failure of segmentation of two or more cervical vertebrae. The neck is short and limited in mobility.
The neural arches of lumbar and sacral vertebrae are not yet closed in 95% of children aged two years. If closure and ossification fail, the result will be a spina bifida occulta.