The vertebral column is what classifies all vertebrates as such, and acts to support the skeleton as part of the axial skeleton further including the rib cage and the skull. It protects the spinal cord contained within, which is one part of the central nervous system, carrying nerves to the whole body.
As the name suggests, the column is composed of 33 vertebrae (in humans), which are the individual bones that line the column from top to bottom. The top 24 vertebrae are spaced by intervertebral discs made of fibrous cartilage, while the bottom 9 are fused e.g. the tailbone.
Furthermore, the vertebral column is split into multiple sections: cervical (vertebrae C1-C7), thoracic (vertebrae T1-T12), lumbar (vertebrae L1-L5), the sacrum and coccyx.
The spine has two inward curvatures (lordotic curves) and two outward curvatures (kypothic curves). The inward ones are at the neck and lower back (cervical and lumbar curves) while the outward ones are the thoracic and sacral curves.
The differences in the vertebrae at the different locations on the column are related to their functions. Not all vertebrae are the same size and shape. Each vertebra has a vertebral foramen where the spinal cord passes through, a vertebral body which forms the part where vertebrae stack onto each other, and multiple processes. Processes such as the spinous process and the transverse process are the outgrowths that give the vertebrae their characteristic appearance.
Cervical, thoracic and lumbar vertebrae are different because they fulfil different functions such as rotation ability, weight carrying capacity and extent of curvature.
Cervical vertebrae are relatively small and delicate. Their flexibility and the flexion and extension at the joints enable extensive head and neck mobility.
Thoracic vertebrae must be connected to the rib cage, therefore the have facets where this link is made. They are sturdier with a thicker laminae which protect the spinal cord running through the vertebrae.
Lumbar vertebrae must support more weight as they are lower down, in addition to allowing some movement, so they have the strongest body, and lack the facets of their thoracic counterparts, as well as the foramen transversarium of their cervical counterparts. The foramen transversarium is for the vertebral artery and vein to pass through in the cervical vertebra.
There are many kinds of deformities of the spine that can be caused through a multitude of ways such as congenital deformities that occur during development, a result of other conditions such as osteoporosis or arthritis, uneven vertebral growth during childhood (Scheuermann’s disease) or due to unknown reasons.
The most common type is scoliosis which means growth to the side. Hunching deformation of the spine is called kyphosis while the opposite curving is called lordosis.
Depending on individual circumstances, treatment can involve watchful waiting of the condition to ensure it doesn’t progress; wearing a brace to correct it if severe and occurring in teenagers who are in a growth spurt; exercise and physiotherapy to help with general health; and surgery to insert metal implants that can redress the curvature.