The spinal column consists of a series of vertebrae (made of bone) attached to each other by discs (made of soft collagen) and stabilized by a complex arrangement of ligaments, muscles, and joints. In contrast to the lumbar spine (lower back portion of the spine), the cervical spine (neck portion of the spine) houses nerves that comprise the spinal cord.
If the spinal column is subject to sufficient trauma, the bony elements of the spinal column can fracture (break). The stability of the spine following the fracture largely depends upon on the severity of the fracture and the integrity of the stabilizing structures. Unstable spines can be associated with an increased risk of the neurologic (nerve) damage. An unstable cervical spine can be associated with an increased risk of the spinal cord damage and can lead to weakness and dysfunction of the arms and legs.
see also Fractures / Broken Bones