Glossary

Click here for the anatomy and function of the spine.

Allograft - A tissue or organ that is transplanted from another human donor.
Anklyosing Spondylitis - Rheumatoid arthritis of the spine.
Annulus Fibrosus - A ring of fibrocartilaginous tissue that surrounds the intervertebral disc.
Anomaly - Malformation; a deviation from normal, usually referring to a congenital or hereditary defect.
Anterior - Situated toward the front of the body.
Anterior Longitudinal Ligament - Begins at the anterior aspect of the base of the occipital bone and is attached to the atlas and anterior surface of all vertebrae including part of the sacrum.
Aorta - The large arterial trunk that carries blood from the heart to be distributed by branch arteries through the body.
Apical Vertebra - The most rotated vertebra in a curve; the most deviated vertebra from the vertical axis of the patient.
Arachnoid - Thin membrane of the spinal cord that lies between the dura mater and the pia mater.
Arthrodesis - The surgical immobilization of a joint so that the bones grow solidly together (joint fusion).
Arthroplasty - Cervical and/or lumbar disc replacement utilizing artificial materials.
Articular Process - Either of two processes on each side of a vertebra that articulate with adjoining vertebra.
Articulate - To unite by means of a joint.
Aseptic - Free of bacterial or fungal contamination.
Atlas - First cervical vertebra.
Atrophy - Wasting away of tissue, usually refers to muscle tissue.
Autograft - A tissue or organ that is transplanted from one part to another part of the same body.
Avascular - Absence of adequate blood supply.
Axis - Second cervical vertebra.
Bifurcation - Site at which any given structure divides in two.
Body Alignment, Balance, and Compensation - The alignment of the midpoint of the occiput over the sacrum in the same vertical plane as the shoulders over hips. In roentgenology (x-ray), when the sum of the angular deviations of the spine in one direction is equal to that in the opposite direction.
Bone Marrow - A network of connective tissue filled with blood vessels that form and develop blood corpuscles, found in the cancellous bone of vertebral bodies.
Brachial Plexus - A complete network of nerves that is formed chiefly by the lower four cervical nerves and the first thoracic nerve, and supplies nerves to the chest, shoulder and arm.
Cancellous - Type of bone with a spongy structure made up of intersecting plates and bars that form small cavities or cells.
Capsule - The general fibrous and ligamentous tissues that act as encasements and enclose the immediate joint area.
Cauda Equina - The roots of the upper sacral nerves that extend beyond the termination of the spinal cord of the first lumbar vertebrae in the form of a bundle of filaments within the spinal canal resembling a horse's tail.
Cauda Equina Syndrome - Sufficient pressure on the nerves in the low back to produce multiple nerve root irritation and commonly loss of bowel and bladder control.
Caudal - Toward the tail, inferior to or bottom point of reference, away from head.
Cephalad - Toward the head or cranial end, uppermost point of reference.
Cervical - Of or relating to the neck. There are seven cervical vertebrae in the spine.
Cervical Plexus - A plexus formed by the anterior division of the four upper cervical nerves.
Chance Fracture - Involves vertebra with horizontal splitting of spinous process and neural arch with disruption through vertebral body; an unstable fracture.
Clavicle - Bone of the pectoral girdle that links the scapula and sternum and is situated just above the first rib on either side of the neck; also called the collarbone.
Cobb Method (of curve measurement) - Select upper and lower end vertebrae. Erect perpendiculars to their transverse axes. They intersect to form the angle of the curve. If the vertebral end plates are poorly visualized, a line through the bottom or top of the pedicles may be used.
Coccyx - The end of the spinal column beyond the sacrum; also referred to as the tailbone.
Comuninuted - More than two fragments.
Computerized Tomography (CT) - System that composes a two dimensional, cross-sectional image (formerly CAT scan ­­- computerized axial tomography).
Compensatory Curve - A curve, which can be structural, above or below a major curve that tends to maintain normal body alignment.
Compression Fracture - Crumbling or smashing of cancellous bone by forces acting parallel to the long axis of bone; applied particularly to vertebral body fractures.
Concave - rounded, depressed surface.
Condyle - Bony projection at the end of a long bone.
Convex - rounded, elevated surface.
Congenital - Existing at or dating from birth.
Conus Medullaris - A tapering lower part of the spinal cord at the level of the first lumbar segment.
Cortical - the dense outer layer of bone.
Corpectomy - Excision of vertebral body with interposition of bone graft.
Creeping Subsituation - Process by which devascularized segment of bone in situ undergoes repair beginning with vascular invasion, followed by bone resorption and new bone formation.
Decompression - Procedure to relieve pressure on spinal cord and nerve roots.
Degenerative Disc Disease - Gradual or rapid deterioration of the chemical composition and physical properties of the disc space.
Dermatome - Refers to the distribution of sensory nerves near the skin that are responsible for pain, tingling and other sensations (or lack of). The afferent nerve fibers (leading to the spinal cord) and cutaneous branches arise from a single posterior spinal nerve root and contain sensory fibers. Loss of sensation in a dermatomal distribution may indicate damage to a nerve root that is caused by a disc prolapse.
Diskectomy - Surgical removal of an intervertebral disc.
Distal - Furthest from the point of reference.
Dorsal - Being located near or toward the back.
Dura Mater - tough outer membrane of the spinal cord.
Edema - Excessive accumulations of fluid in soft tissue causing swelling.
End Vertebrae - The most cephalic vertebra of a curve, whose superior surface tilts maximally toward the concavity of the curve; the most caudal vertebra whose inferior surface tilts maximally toward the concavity of the curve.
Epiphyseal Plate - The cartilage that contains an epiphysis, unites it with the shaft and is the site of longitudinal growth of the bone.
Epidural - a local anesthetic injected into the space between the outer membrane covering the spinal cord and the overlying bones of the spine.
Esophagus - Portion of the gut between the mouth and stomach encountered in anterior neck fusion (food tube).
Extension - Bending the back posteriorly.
Facet - A smooth flat or nearly flat surface covered with hyaline cartilage.
Failure of Segmentation - Failure of a portion or all of two or more adjoining vertebrae to separate into normal units.
Flexion - To bend from join (anterior or lateral).
Foramen - A small opening, perforation or orifice.
Foramen Magnum - The opening of in the skull through which the spinal cord passes to become the medulla oblongata.
Foraminotomy - Removes some overlying bone to enlarge the foramen.
Frankel Classification - A classification system for neurological deficit:

• Grade A - Complete motor and sensory involvement
• Grade B - Complete motor, some sensory
• Grade C - functionally useless motor
• Grade D - functional motor
• Grade E - No neurological involvement

Frontal Plane - A longitudinal plane at right angles to the sagital plane; splits the body into anterior and posterior.
Fusion - The surgical immobilization of a joint.
Graft - A piece of living tissue used to join two parts together.
Gibbus - A sharply angular kyphos.
Herniated Disc - A disc that is protruding outside of its normal area.
Herniated nucleus pulposus - Fibrous extrusion of semi fluid nucleus pulposus through a ruptured intervertebral disc; damage results from pressure on the spinal cord or nerve roots, causing pain and disability.
Hernivertebra - Missing lateral portion of vertebral body, resulting in a wedge shape; the net result of a hernivertebra is an abnormal curve.
Hyperkyphosis - An abnormal backward curvature of the spine - hunchback.
Iatrogenic - Induced inadvertently by the medical treatment or procedures of a physician.
Iliac Crest - The most superior crest of the Ilium.
Ilium - The dorsal, upper and largest of the three bones composing either lateral half of the pelvis.
Inclinometer - An instrument used to measure the angle of thoracic inclination or rib hump.
Inferior - situated below or closer to the feet than another part.
In Situ - Natural or original position.
Interbody Fusion - The surgical immobilization of...
Internal Fixation -
Interspinous Ligament - Any of the thin membranous ligaments that connect the spinous processes of contiguous vertebrae.
Intervertebral Disc - Any of the tough elastic discs that are interposed between the centrum of adjoining vertebrae and that consist of an outer annulus fibrous enclosing an inner nucleus pulposus.
Intervertabral foramen - Any of the openings that give passage to the spinal nerves from the spinal canal and are formed by the juxtaposition of superior and inferior notches in the pedicles of contiguous vertebrae.
In Vivo - In the living body of a plant or animal or in a real-life situation.
Kyphosis - Normal curvature of the thoracic spine; the concavity of the curve is anterior.
Lamina - The part of the neural arch of a vertebra extending from the pedicle to the median line.
Laminectomy - Surgical removal of the lamina.
Laminotomy - Surgical removal of part of the lamina.
Lateral - Of or relating to the side.
Lateral Mass - The lateral expansion of the spinal ring in the cervical spine, where there is a specific place through which the vertebral artery travels.
Lesion - An abnormal change in structure of an organ or part due to injury or disease.
Ligament - A tough band of tissue that serves to connect the articular extremities of bones.
Ligamentum Flava - A series of ligaments connecting the lamina of adjacent vertebrae from the axis to the sacrum.
Ligamentotaxis - Use of the ligaments to reduce fractures.
Load sharing - Structural support through grafts and/or implants both posteriorly and anteriorly.
Lordosis - Curvature of the spine found in the cervical and lumbar regions; the concavity of the curve is posterior.
Lumbar - Of or relating to the vertebrae between the thoracic vertebrae - located in the chest area - and the sacrum - the bone at the base of the spine.
Lumbar Plexus - A plexus formed by the anterior of ventral division of the four upper lumbar nerves, of which the first is usually supplemented by a communication from the twelfth thoracic nerve.
Magnetic Resonance Imaging (MRI) - Allows observation of anatomic detail in soft tissue and bone that is not apparent on radiographs.
Malunion - Incomplete or faulty union as of the fragments of a fractured bone.
Manipulate - To treat or operate with the hands or by mechanical means especially in a skillful manner.
Medial - Lying or extending in the middle or toward the median axis or midline of the body.
Medulla Oblongata - Brain Stem.
Meninges - The three membranes that envelope the brain and spinal cord.
Meningitis - Inflammation of the meninges of the brain or spinal cord caused by infectious agents such as bacteria, fungi or viruses.
Myelography - Radiographic exam with air or contrast medium injected into the subarachnoid space under fluoroscopy to examine the spinal cord and canal for possible disc protrusions or lesion; mycelogram.
Myelopathy - Functional disturbance and pathological (uncontrollable, relating to disease) changes in the spinal cord.
Necrosis - Death of tissue or group of cells in tissue from trauma or disease.
Non-structural Curve - A curve that has no structural component and that corrects or overcorrects on recumbent side-bending reoetgenograms.
Nuchal Ligament - A ligament that runs along the posterior midline of the occipital bone and extends through the trough of the cervical curvature of the posterior neck; this ligament helps resist passive flexion of the head.
Nucleus Pulposus - An elastic pulpy mass lying in the center of each intervertebral disc.
Occiput - The back part of the head or skull.
Odontoid Process - A toothlike process that projects from the anterior end of the centrum on the axis (C2) in the spinal column; serves as a pivot on which the atlas (C1) rotates; also known as the dens.
Orthopedic - Relating to disorders of the bones, joints, ligaments or muscles.
Ossification - Process of forming bone.
Osteoblast - Bone-forming cell.
Osteoclast - Bone cell.
Osteoconduction - Function of bone graft to act as a scaffolding for new bone.
Osteoinduction - Stimulate new bone formation.
Osteophyte - Bony outgrowth, usually found around joint area of bone.
Osteoporosis - A condition that is characterized by a decrease in bone mass with decreased density and enlargement of bone spaces producing porosity and fragility.
Paraplegia - Paralysis of the lower half of the body with involvement of both legs usually due to disease of, or injury to, the spinal cord.
Paresis - Incomplete loss of voluntary muscle function.
Paresthesia - Abnormal sensations such as numbness, burning, tingling and crawling due to central or peripheral nerve lesions such as multiple sclerosis or locomotor ataxia.
Pedicle - The basal part of each side of the neural arch of a vertebra connecting the lamina with the vertebral body.
Pelvic Obliquity - Deviation of the pelvis from the horizontal in the frontal plane; fixed pelvic obliquities can be attributable to contractures either above or below the pelvis.
Percutaneous - Effected or performed through the skin.
Peritoneum - The smooth transparent serous membrane that lines the cavity of the abdomen.
Pia Mater - The delicate and highly vascular membrane of connective tissue around the brain and spinal cord lying internal to the arachnoid and dura mater.
Plexus - A network of anastomotic or interlacing blood vessels or nerves.
Posterior - Situated behind or toward the back.
Posterior Longitudinal Ligament - Arises from the posterior aspect of the base of the occipital bone, covers the dens and runs over the posterior surface of all vertebral bodies down to the coccyx.
Primary Curve - The first or earliest of several scoliotic curves to appear, if identifiable.
Process - A part of the mass of an organism or organic structure that projects outward from the main mass.
Prone -Lying face down.
Proximal - Situated closest to the point of reference.
Pseudoarthrosis - Abnormal union between points of bone; also referred to as a false joint.
Quadriplegia - Paralysis of both arms and both legs.
Rhizotomy - Surgery in which spinal nerves are cut in order to relieve pain or high blood pressure.
Radiculopathy - Any pathological condition of the nerve roots.
Radiolucent - Permitting free passage of radiant energy (x-ray) throughout an area, with dark appearance on exposed film.
Radiopaque - Preventing passage of radiant energy (x-ray) thus allowing the representative area to appear light or white on exposed film.
Reduction - The replacement or realignment of a body part in normal position or restoration of a bodily condition to normal.
Retraction - A pulling back of tissue, whether done mechanically at the time of surgery or by scar formation.
Rib Hump - The prominence of the ribs on the convexity of a spinal curvature, usually due to vertebral rotation, best exhibited on forward bending.
Risser Sign - For skeletal maturity, the degree of capping of the apophysis from beginning (Grade 1) to completion (Grade 4).
Roentgenogram - A photograph made with x-rays.
Rongeur - To cut into bone with a sharp biting instrument called a Rongent, usually to remove bone that is diseased or obstructing visualization of deeper structures.
Sacral Ala - The wing-like anatomic process of the sacrum where it articulates with the ilium.
Sacral Crest (Median) - A crest of tubercle on the midline of the dorsal surface of the sacrum.
Sacral Plexus - A nerve plexus that lies against the posterior and lateral walls of the pelvis, is formed by the union of the lumbosacral trunk and the first, second and third sacral nerves and continues into the thigh as the sciatic nerve.
Sacral Promontory - The inwardly projecting anterior part of the body of the first sacral vertebra.
Sacrum - the part of the spinal column that forms a part of the pelvis and consists of five united vertebrae.
Sagital Plane - Divides the body into right and left parts; these parts are not necessarily equal.
Schmorl Node - Developmental change resulting in inferior or superior extension of the intervertebral disc into the vertebral bodies.
Sciatica - Pain along the course of the sciatic nerve located at the back of the hip.
Sciatic Nerve - Either of the pair of largest nerves in the body that arise on each side from the sacral plexus and that pass out of the pelvis through the greater sciatic foramen and down the back of the thigh to its lower third where division into the tibial and common peroneal nerves occur.
Sacroiliac - Relating to the sacrum and the upper portion of the hipbone or to the joint between the sacrum (bone at the base of the spine) and the hipbone.
Scoliosis - A three-dimensional deformity of the spine which involves loss of the normal thoracic kyphosis, side shifting of the apical vertebra and rotation of the apical vertebra along the longitudinal axis of the spine.

Adolescent Scoliosis
Spinal curvature presenting at or about the onset of puberty and before maturity.
Adult Scoliosis
Spinal curvature existing after skeletal maturity.
Congenital Scoliosis
Scoliosis due to congenitally anomalous vertebral development.
Double Major Scoliosis
A scoliosis with two structural curves.
Double Thoracic Curves
Two structural scoliotic curves within the thoracic spine.
Idiopathic Scoliosis
A structural spinal curvature for which no cause is established.
Infantile Scoliosis
Spinal curvature developing during the first three years of life.
Juvenile Scoliosis
Spinal curvature developing between skeletal age of three years and the onset of puberty.
Major Curve
Term used to designate the largest structural curve in scoliosis.
Minor Curve
Term used to refer to the smallest curve which is always more flexible than the major curve in scoliosis.

Scotty Dog Sign - For spondylolysis, the oblique radiograph reveals what looks like a Scotty dog; the "eye" is a pedicle seen end on; the nose, the transverse process; the collar, the lysis (split); the body the lamina; the tail, the posterior spinous process; the ears, the superior facet; and the forefoot, the inferior facet.
Sepsis - Denotes the presence of infection caused by bacteria.
Slough - Spontaneous separation of devitalized tissue from living tissue.
SNRB (Selective Nerve Root Block) -
Spina bifida - Congenital defect common in the low back (lumbosacral region) of infants in which part of a vertebra (and in severe cases, nerve tissue) does not fully develop leaving a portion of the spinal cord exposed.
Spinal Canal - The space between the vertebral body anteriorly and the lamina and spinal process posteriorly. The spinal cord and nerve roots extend to the level of the second lumbar segment in adults and the second sacral segment in infants. Below this level are numerous nerve roots from the spinal cord.
Spinal Cord - The thick longitudinal cord of nervous tissue that extends along the back, dorsal to the bodies of the vertebrae and is enclosed in the spinal canal formed by their neural arches, gives off at intervals pairs of spinal nerves to the various parts of the trunk and limbs, serves not only as a pathway for nervous impulses to and from the brain but also as a center for carrying out and coordinating many reflex actions independently of the brain.
Spinal Fusion - Surgical fusion of two or more vertebrae for remedial immobilization of the spine.
Spinous Process - The median spine-like or plate-like dorsal process of the neural arch of a vertebra.
Spondylitis - Inflammation of the vertebrae.
Spondylolisthesis - Forward displacement of a lumbar vertebra on the one below it.
Spondylolysis - Disintegration or dissolution of a vertebra; acute disassociation of the par interarticularis.
Spondylosis - Bony replacement of ligaments around disc space of the spine, associated with decreased mobility and eventual fusion.
Stenosis - A narrowing or constriction off the diameter of a bodily passage.
Subchondral Bone - Named for the bone immediately next to the joint cartilage.
Subdural - Situated, occurring or performed under the dura mater or between the dura mater and the arachnoid.
Subluxation - Partial dislocation.
Superior - Situated toward the head or above another part.
Supraspinous Ligament - Joins the tips of the spinous processes from the seventh cervical vertebra to the sacrum.
Supine - Lying on back, face up.
Synoviun - Inner lining of a joint cavity that is a one- or two-layer cell membrane (synovial membrane) on a bed of fat. The synovial membrane normally produces and absorbs a clear synovial fluid, which lubricates and feeds cartilage surfaces.
Thoracic Vertebrae - Any of the twelve vertebrae dorsal to the thoracic region and characterized by articulation with the ribs.
Thoracotomy - Surgical incision of the chest wall.
Trabecular Pattern - Refers to arrangement of trabecular bone that, when seen on radiographs or in cross-section, shows a pattern of arches or other designs providing the structural needs of the bone.
Trachea - The windpipe.
Traction - The pulling force exerted on a skeletal structure by means of a special device or apparatus.
Transverse - Made at right angles to the anterior-posterior axis of the body.
Umbilicus - Navel.
Uncinate Process - The superior surface of each vertebral body in the lower cervical spine is concave and has two projecting lips, which form the uncovertebral joint with the vertebra above. These two joints provide stability for lateral flexion and extension.
Unsegmented Bar - Fusion on one side or the other of the vertebrae, which may involve the posterior elements or vertebral bodies; may occur at multiple levels and skip vertebral segments and may result in severe curves.
Vertebrae - A bone of the spinal column.

• Are you a study candidate for artificial disc replacement?

• What every patient should know

• Privacy