Answer
The vertebral column is made up of 33 or 34 vertebrae in infancy and child hood but by the age of 30 (26-30) some of these have fused leaving the adult with 26 separate bones in the vertebral column.
In a child there are five groups of separate vertebral bones; they are numbered from superior to inferior (upper tp lower). The five classes are related to regions of the body neck (cervical), chest (thoracic), lower back (lumbar), sacral, and coccygeal.
1. Cervical vertebrae: there are seven cervical vertebrae (the atlas and the axis are atypical in shape. (7).
2. Thoracic vertebrae: there are 12 thoracic vertebrae (12)
3. Lumbar vertebrae: there are 5 lumbar vertebrae (5)
4, Sacral vertebrae: there are 5 sacral vertebrae (5)
5. Coccygeal vertebrae there are 4 small coccygeal vertebrae (4)
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Total = 33
Work Step by Step
In infants and in children, the number of separate vertebral bones is 33 or 34-- typically 33. However, the 5 sacral bones (separate in infants and young children), fuse to from a single bone --the sacrum-- by the age of 26 (16-26). The 4 or 5 coccygeal vertebrae also fuse to form a single bone--the coccyx--by the age of 30 (20-30). Therefore, in the adult, the vertebral column typically consists of 26 bones .
The vertebrae in the different regions or curvatures of the vertebral column--cervical, thoracic, lumbar, sacral, coccygeal--are named for those curvatures. They are numbered within each region/curvature from superior to inferior positions (from top to bottom). The vertebrae in the cervical (neck) region/curvature are named C 1-C7; those in the chest region or thoracic curve are named T1-T12; those in the lumbar region are named L1-L5; sacral vertebrae, before fusion, are S1-S5, and the small coccygeal vertebrae , before fusion, are Co1-Co 4.
There are individual variations fro person to person in what group the last lumbar vertebra choses to join--lumbar or sacral; also, in some cases the first sacral vertebra may fuse with the lumbar group in preference to the sacral.
