Final answer:
The vertebral column consists of five regions: the cervical vertebrae (C1-C7), thoracic vertebrae (T1-T12), lumbar vertebrae (L1-L5), sacrum, and coccyx. The sacrum and coccyx are formed from the fusion of vertebrae, which begins after age 20 and completes in middle age. The vertebral column has 33 vertebrae at birth, which eventually reduces to 24 in adults.
Step-by-step explanation:
Regions of the Vertebral Column
The vertebral column, also known as the spinal column, is structured into five regions. The neck hosts seven cervical vertebrae (C1-C7), connected superiorly to the skull and successively to each other. Following these are the 12 thoracic vertebrae (T1-T12) associated with the chest. In the lower back, we find the five lumbar vertebrae (L1-L5). The sacrum, located within the pelvis, is formed by the fusion of five sacral vertebrae in adults, while the coccyx, or tailbone, is created by the fusion of four small coccygeal vertebrae. These latter fusions do not complete until middle age, beginning after 20 years old.
The vertebral column goes through changes from infancy to adulthood. Initially comprised of 33 vertebrae, this number reduces to 24 as we grow, due to the fusion of several vertebrae to form the sacrum and coccyx. The vertebral column also presents four curvatures which add to its strength and flexibility: the cervical, thoracic, lumbar, and sacrococcygeal curves.