There are 33 vertebrae in the spinal column divided into five sections: cervical, thoracic, lumbar, sacral and coccyx vertebrae. Each vertebra has a body, an arch and multiple spinal processes, according to Mayfield Clinic.
The spinal column protects the spinal cord and bears most of the weight and stress from a person’s daily activities. The main part of each vertebra is the vertebral body, which increases in size from the neck to the sacrum, according to Cedars-Sinai. Vertebral bodies provide attachment points for intervertebral discs and withstand compression in order to protect the spinal cord. Intervertebral discs are gel-filled cushions located between each vertebra that prevent the vertebrae from rubbing on one another. The annulus, or outer ring of each disc, absorbs fluid pushed out during the compression of daily activities.
The spinal arch is made up of two pedicles and two laminae, which together form the spinal canal, which is the tunnel in which the spinal cord and nerve roots lie, explains the Mayfield Clinic. Pedicles provide side protection for the spinal canal, and the laminae form the roof of the spinal canal. Spinous and transverse processes provide bony attachments for muscles. The spinous processes are attached to the processes above and below by ligaments, and back muscles attach to the spine via the transverse processes. Each vertebra makes a connection with the vertebra above and below it via a facet joint on the lateral sides, and facet joints are surrounded by a synovial capsule.