Normal Spinal Anatomy

The series of bones and discs that surround and support the spinal cord in the back are collectively referred to as the spinal column. The spinal column is made up of 33 vertebrae that are named in groups according to the anatomical regions they occupy: cervical, thoracic, lumbar, sacral, and coccygeal. There are seven cervical vertebrae (C1-C7), twelve thoracic (T1-T12), five lumber (L1-L5), five sacral (S1-S5), and four coccygeal. The vertebrae from the cervical, thoracic and lumbar regions are separated by cartilaginous disks, while those of the sacral and coccygeal regions are fused together and do not contain disks.

The typical vertebra consists of two parts: an anterior segment called the body and a posterior segment comprised of a central spinous process and two laterally projecting transverse processes. Between these segments is a space referred to as the spinal canal. The spinal cord lies within the spaces of the spinal canal and is protected by the boney structures of the surrounding vertebrae.