Glossary

Iatrogenic - Occurring without known cause. Self-originated.

Iliac Bone - A part of the pelvic bone that is above the hip joint and from which autogenous bone grafts are frequently obtained.

Iliac Crest - The large, prominent portion of the pelvic bone at the belt line of the body.

Immobilization - Limitation of motion or fixation of a body part usually to promote healing.

In vitro - Describing biological phenomena that are made to occur outside the living body (traditionally in a test tube). In vitro is Latin for in glass.

In vivo - Within a living body. In vivo is Latin for in life.

Inferior - Situated below or directed downward.

Infra-pedicular level - The level between the axial planes of the inferior edge of the pedicle craniad to the disc in question and the inferior end-plate of the vertebral body above. Syn: superior vertebral notch.

Internal Fixation - The immobilization of bone fragments or joints with implants in order to promote healing or fusion.

Intervertebral Disc - See Disc.

Intervertebral osteochondrosis - Degenerative process of the spine involving the vertebral body end-plates, the nucleus pulposus, and the anulus fibrosus, which is characterized by disc space narrowing, vacuum phenomenon, and vertebral body reactive changes.

Intra-anular displacement - Displacement of central, predominantly nuclear, tissue to a more peripheral site within the disc space, usually into a fissure in the anulus.