Glossary

Facet - A posterior structure of a vertebra which articulates with a facet of an adjacent vertebra to form a facet joint that allows motion in the spinal column. Each vertebra has two superior and two inferior facets.

Facetectomy - Excision of a facet.

Fatigue Fracture - A fracture that occurs in bone or in other materials, including metal, as a result of repeated stress as opposed to a single injury.

Fibrosis - The replacement of normal tissue with scar tissue.

Fissure of anulus -Separations between anular fibers, avulsion of fibers from their vertebral body insertions, or breaks through fibers that extend radially, transversely, or concentrically, involving one or more layers of the anular lamellae. Syn: tear of anulus, torn anulus.

Focal protrusion - Protrusion of disc material so that the base of the displaced material is less than 25% (90 degrees) of the circumference of the disc.

Foramen - A natural opening or passage in bone.

Foraminal zone - The zone between planes passing through the medial and lateral edges of the pedicles.

Fracture - A disruption of the normal continuity of bone.

Fusion - Union or healing of bone.