The portion of a spinal nerve in close proximity to its origin from the spinal cord.

The bony arch of the posterior aspect of a vertebra that surrounds the spinal cord, also referred to as the vertebral arch.

The surgical specialty involved in the treatment of disorders of the brain, spinal cord, and peripheral nerves.

Failure of the fragments of a fractured bone to heal or to obtain bony fusion following an arthrodesis.

The semi-gelatinous tissue in the center of an intervertebral disc. It is surrounded and contained by the annulus fibrosus which prevents this material from protruding outside the disc space.