Glossary

Paracentral - In the right or left central zone of the vertebral canal. See central zone. Note: The terms right central or left central are preferable when speaking of a single site when the side can be specified, as when reporting the findings of imaging procedures. Paracentral is appropriate if the side is not significant or when speaking of mixed sites.

Pathology - The study of disease states.

Pedicle - The part of each side of the neural arch of a vertebra. It connects the lamina with the vertebral body.

Pedicular level - The level between axial planes through the upper and lower edges of the pedicle. Note: The pedicular level may be further designated with reference to the disc in question as "pedicular level above" or "pedicular level below."

Peridural membrane - A delicate, translucent membrane that attaches to the undersurface of the deep layer of the posterior longitudinal ligament, and extends laterally and posteriorly, encircling the bony spinal canal outside the dura. The veins of Batson's plexus lie on the dorsal surface of the peridural membrane and pierce it ventrally

Periosteum - A fibrous membrane that covers the surface of bone except at the end of the bones where it is covered with cartilage as part of a joint. In children, periosteum is involved in forming new bone and molding the configuration of bone; and in the adult, the periosteum forms new bone secondary to injury or infection.

Physical Therapy - The treatment consisting of exercising specific parts of the body such as the legs, arms, hands or neck, in an effort to strengthen, regain range of motion, relearn movement and/or rehabilitate the musculoskeletal system to improve function.

Physiology - The science of the functioning of living organisms, and of their component systems or parts.

Posterior - Located behind a structure, such as relating to the back side of the human body.

Prolapsed disc - A herniated disc in which disc tissue has protruded or extruded at the level of the disc and below into the supra-pedicular level.

Prosthesis - An artificial body part such as an artificial leg or arm. The term prosthesis is also used to describe some of the implants used in the body such as a hip or knee replacement device.

Protruded disc - A herniated disc in which the greatest distance, in any plane, between the edges of the disc material beyond the disc space is less than the distance between the edges of the base in the same plane.

Proximal - Nearest the center of the body.

Pseudoarthrosis (also Pseudarthrosis) - A form of a non-union in which there is the formation of a false joint with some cartilage covering the ends of the bones and a cavity containing fluid that resembles a normal joint.