Intervertebral Disc: Any of the 23 plates of fibrocartilage found between the bodies of adjacent VERTEBRAE.Intervertebral Disc Degeneration: Degenerative changes in the INTERVERTEBRAL DISC due to aging or structural damage, especially to the vertebral end-plates.Intervertebral Disc Displacement: An INTERVERTEBRAL DISC in which the nucleus pulposus has protruded through surrounding fibrocartilage. This occurs most frequently in the lower lumbar region.Lumbar Vertebrae: VERTEBRAE in the region of the lower BACK below the THORACIC VERTEBRAE and above the SACRAL VERTEBRAE.Fibrocartilage: A type of CARTILAGE whose matrix contains large bundles of COLLAGEN TYPE I. Fibrocartilage is typically found in the INTERVERTEBRAL DISK; PUBIC SYMPHYSIS; TIBIAL MENISCI; and articular disks in synovial JOINTS. (From Ross et. al., Histology, 3rd ed., p132,136)Spinal DiseasesSpine: The spinal or vertebral column.Intervertebral Disc Chemolysis: The dissolving of the nucleus pulposus, the semi-gelatinous tissue of a displaced INTERVERTEBRAL DISC. It is usually achieved by the direct injection of a proteolytic enzyme, especially CHYMOPAPAIN, into the herniated disc.Aggrecans: Large HYALURONAN-containing proteoglycans found in articular cartilage (CARTILAGE, ARTICULAR). They form into aggregates that provide tissues with the capacity to resist high compressive and tensile forces.Diskectomy: Excision, in part or whole, of an INTERVERTEBRAL DISC. The most common indication is disk displacement or herniation. In addition to standard surgical removal, it can be performed by percutaneous diskectomy (DISKECTOMY, PERCUTANEOUS) or by laparoscopic diskectomy, the former being the more common.Compressive Strength: The maximum compression a material can withstand without failure. (From McGraw-Hill Dictionary of Scientific and Technical Terms, 5th ed, p427)Cervical Vertebrae: The first seven VERTEBRAE of the SPINAL COLUMN, which correspond to the VERTEBRAE of the NECK.Lumbosacral Region: Region of the back including the LUMBAR VERTEBRAE, SACRUM, and nearby structures.Notochord: A cartilaginous rod of mesodermal cells at the dorsal midline of all CHORDATE embryos. In lower vertebrates, notochord is the backbone of support. In the higher vertebrates, notochord is a transient structure, and segments of the vertebral column will develop around it. Notochord is also a source of midline signals that pattern surrounding tissues including the NEURAL TUBE development.Chymopapain: A cysteine endopeptidase isolated from papaya latex. Preferential cleavage at glutamic and aspartic acid residues. EC 3.4.22.6.Weight-Bearing: The physical state of supporting an applied load. This often refers to the weight-bearing bones or joints that support the body's weight, especially those in the spine, hip, knee, and foot.Spinal Osteophytosis: Outgrowth of immature bony processes or bone spurs (OSTEOPHYTE) from the VERTEBRAE, reflecting the presence of degenerative disease and calcification. It commonly occurs in cervical and lumbar SPONDYLOSIS.Thoracic Vertebrae: A group of twelve VERTEBRAE connected to the ribs that support the upper trunk region.Discitis: Inflammation of an INTERVERTEBRAL DISC or disk space which may lead to disk erosion. Until recently, discitis has been defined as a nonbacterial inflammation and has been attributed to aseptic processes (e.g., chemical reaction to an injected substance). However, recent studies provide evidence that infection may be the initial cause, but perhaps not the promoter, of most cases of discitis. Discitis has been diagnosed in patients following discography, myelography, lumbar puncture, paravertebral injection, and obstetrical epidural anesthesia. Discitis following chemonucleolysis (especially with chymopapain) is attributed to chemical reaction by some and to introduction of microorganisms by others.Collagen Type II: A fibrillar collagen found predominantly in CARTILAGE and vitreous humor. It consists of three identical alpha1(II) chains.Biomechanical Phenomena: The properties, processes, and behavior of biological systems under the action of mechanical forces.Low Back Pain: Acute or chronic pain in the lumbar or sacral regions, which may be associated with musculo-ligamentous SPRAINS AND STRAINS; INTERVERTEBRAL DISK DISPLACEMENT; and other conditions.Sciatica: A condition characterized by pain radiating from the back into the buttock and posterior/lateral aspects of the leg. Sciatica may be a manifestation of SCIATIC NEUROPATHY; RADICULOPATHY (involving the SPINAL NERVE ROOTS; L4, L5, S1, or S2, often associated with INTERVERTEBRAL DISK DISPLACEMENT); or lesions of the CAUDA EQUINA.Spinal Fusion: Operative immobilization or ankylosis of two or more vertebrae by fusion of the vertebral bodies with a short bone graft or often with diskectomy or laminectomy. (From Blauvelt & Nelson, A Manual of Orthopaedic Terminology, 5th ed, p236; Dorland, 28th ed)Sacrum: Five fused VERTEBRAE forming a triangle-shaped structure at the back of the PELVIS. It articulates superiorly with the LUMBAR VERTEBRAE, inferiorly with the COCCYX, and anteriorly with the ILIUM of the PELVIS. The sacrum strengthens and stabilizes the PELVIS.Myelography: X-ray visualization of the spinal cord following injection of contrast medium into the spinal arachnoid space.Proteoglycans: Glycoproteins which have a very high polysaccharide content.Radiculopathy: Disease involving a spinal nerve root (see SPINAL NERVE ROOTS) which may result from compression related to INTERVERTEBRAL DISK DISPLACEMENT; SPINAL CORD INJURIES; SPINAL DISEASES; and other conditions. Clinical manifestations include radicular pain, weakness, and sensory loss referable to structures innervated by the involved nerve root.Collagen Type IX: A fibril-associated collagen usually found crosslinked to the surface of COLLAGEN TYPE II fibrils. It is a heterotrimer containing alpha1(IX), alpha2(IX) and alpha3(IX) subunits.Glycosaminoglycans: Heteropolysaccharides which contain an N-acetylated hexosamine in a characteristic repeating disaccharide unit. The repeating structure of each disaccharide involves alternate 1,4- and 1,3-linkages consisting of either N-acetylglucosamine or N-acetylgalactosamine.Scoliosis: An appreciable lateral deviation in the normally straight vertical line of the spine. (Dorland, 27th ed)Diskectomy, Percutaneous: Percutaneous excision of a herniated or displaced INTERVERTEBRAL DISC by posterolateral approach, always remaining outside the spinal canal. Percutaneous nucleotomy was first described by Hijikata in Japan in 1975. In 1985 Onik introduced automated percutaneous nucleotomy which consists in percutaneous aspiration of the nucleus pulposus. It is carried out under local anesthesia, thus reducing the surgical insult and requiring brief hospitalization, often performed on an outpatient basis. It appears to be a well-tolerated alternative to surgical diskectomy and chymopapain nucleolysis.Spondylolisthesis: Forward displacement of a superior vertebral body over the vertebral body below.Spinal Stenosis: Narrowing of the spinal canal.Magnetic Resonance Imaging: Non-invasive method of demonstrating internal anatomy based on the principle that atomic nuclei in a strong magnetic field absorb pulses of radiofrequency energy and emit them as radiowaves which can be reconstructed into computerized images. The concept includes proton spin tomographic techniques.Laminectomy: A surgical procedure that entails removing all (laminectomy) or part (laminotomy) of selected vertebral lamina to relieve pressure on the SPINAL CORD and/or SPINAL NERVE ROOTS. Vertebral lamina is the thin flattened posterior wall of vertebral arch that forms the vertebral foramen through which pass the spinal cord and nerve roots.Cadaver: A dead body, usually a human body.Extracellular Matrix: A meshwork-like substance found within the extracellular space and in association with the basement membrane of the cell surface. It promotes cellular proliferation and provides a supporting structure to which cells or cell lysates in culture dishes adhere.Total Disc Replacement: The replacement of intervertebral discs in the spinal column with artificial devices. The procedure is done in the lumbar or cervical spine to relieve severe pain resulting from INTERVERTEBRAL DISC DEGENERATION.Extracellular Matrix Proteins: Macromolecular organic compounds that contain carbon, hydrogen, oxygen, nitrogen, and usually, sulfur. These macromolecules (proteins) form an intricate meshwork in which cells are embedded to construct tissues. Variations in the relative types of macromolecules and their organization determine the type of extracellular matrix, each adapted to the functional requirements of the tissue. The two main classes of macromolecules that form the extracellular matrix are: glycosaminoglycans, usually linked to proteins (proteoglycans), and fibrous proteins (e.g., COLLAGEN; ELASTIN; FIBRONECTINS; and LAMININ).Back Pain: Acute or chronic pain located in the posterior regions of the THORAX; LUMBOSACRAL REGION; or the adjacent regions.Spinal Canal: The cavity within the SPINAL COLUMN through which the SPINAL CORD passes.Polyradiculopathy: Disease or injury involving multiple SPINAL NERVE ROOTS. Polyradiculitis refers to inflammation of multiple spinal nerve roots.Stress, Mechanical: A purely physical condition which exists within any material because of strain or deformation by external forces or by non-uniform thermal expansion; expressed quantitatively in units of force per unit area.Chondrocytes: Polymorphic cells that form cartilage.Decompression, Surgical: A surgical operation for the relief of pressure in a body compartment or on a body part. (From Dorland, 28th ed)Biglycan: A small leucine-rich proteoglycan found in a variety of tissues including CAPILLARY ENDOTHELIUM; SKELETAL MUSCLE; CARTILAGE; BONE; and TENDONS. The protein contains two glycosaminoglycan chains and is similar in structure to DECORIN.Spinal Injuries: Injuries involving the vertebral column.Procollagen N-Endopeptidase: An extracellular endopeptidase which excises a block of peptides at the amino terminal, nonhelical region of the procollagen molecule with the formation of collagen. Absence or deficiency of the enzyme causes accumulation of procollagen which results in the inherited connective tissue disorder--dermatosparaxis. EC 3.4.24.14.Ligaments: Shiny, flexible bands of fibrous tissue connecting together articular extremities of bones. They are pliant, tough, and inextensile.Finite Element Analysis: A computer based method of simulating or analyzing the behavior of structures or components.Spondylitis: Inflammation of the SPINE. This includes both arthritic and non-arthritic conditions.Tartrazine: An anionic, hydrophilic azo dye with an orange-yellow color used in fabrics, foods and cosmetics, and as a biological stain.Keratan Sulfate: A sulfated mucopolysaccharide initially isolated from bovine cornea. At least two types are known. Type I, found mostly in the cornea, contains D-galactose and D-glucosamine-6-O-sulfate as the repeating unit; type II, found in skeletal tissues, contains D-galactose and D-galactosamine-6-O-sulfate as the repeating unit.Range of Motion, Articular: The distance and direction to which a bone joint can be extended. Range of motion is a function of the condition of the joints, muscles, and connective tissues involved. Joint flexibility can be improved through appropriate MUSCLE STRETCHING EXERCISES.Lordosis: The anterior concavity in the curvature of the lumbar and cervical spine as viewed from the side. The term usually refers to abnormally increased curvature (hollow back, saddle back, swayback). It does not include lordosis as normal mating posture in certain animals ( = POSTURE + SEX BEHAVIOR, ANIMAL).Internal Fixators: Internal devices used in osteosynthesis to hold the position of the fracture in proper alignment. By applying the principles of biomedical engineering, the surgeon uses metal plates, nails, rods, etc., for the correction of skeletal defects.SOX9 Transcription Factor: A SOXE transcription factor that plays a critical role in regulating CHONDROGENESIS; OSTEOGENESIS; and male sex determination. Loss of function of the SOX9 transcription factor due to genetic mutations is a cause of CAMPOMELIC DYSPLASIA.TailZygapophyseal Joint: The joint that occurs between facets of the interior and superior articular processes of adjacent VERTEBRAE.Regeneration: The physiological renewal, repair, or replacement of tissue.Dog Diseases: Diseases of the domestic dog (Canis familiaris). This term does not include diseases of wild dogs, WOLVES; FOXES; and other Canidae for which the heading CARNIVORA is used.Keratin-8: A type II keratin found associated with KERATIN-18 in simple, or predominately single layered, internal epithelia.Kyphosis: Deformities of the SPINE characterized by an exaggerated convexity of the vertebral column. The forward bending of the thoracic region usually is more than 40 degrees. This deformity sometimes is called round back or hunchback.Cartilage: A non-vascular form of connective tissue composed of CHONDROCYTES embedded in a matrix that includes CHONDROITIN SULFATE and various types of FIBRILLAR COLLAGEN. There are three major types: HYALINE CARTILAGE; FIBROCARTILAGE; and ELASTIC CARTILAGE.Epidural Space: Space between the dura mater and the walls of the vertebral canal.Cattle: Domesticated bovine animals of the genus Bos, usually kept on a farm or ranch and used for the production of meat or dairy products or for heavy labor.Spondylolysis: Deficient development or degeneration of a portion of the VERTEBRA, usually in the pars interarticularis (the bone bridge between the superior and inferior facet joints of the LUMBAR VERTEBRAE) leading to SPONDYLOLISTHESIS.Immunohistochemistry: Histochemical localization of immunoreactive substances using labeled antibodies as reagents.Spondylosis: A degenerative spinal disease that can involve any part of the VERTEBRA, the INTERVERTEBRAL DISK, and the surrounding soft tissue.Aging: The gradual irreversible changes in structure and function of an organism that occur as a result of the passage of time.Spinal Cord Compression: Acute and chronic conditions characterized by external mechanical compression of the SPINAL CORD due to extramedullary neoplasm; EPIDURAL ABSCESS; SPINAL FRACTURES; bony deformities of the vertebral bodies; and other conditions. Clinical manifestations vary with the anatomic site of the lesion and may include localized pain, weakness, sensory loss, incontinence, and impotence.Laryngeal Cartilages: The nine cartilages of the larynx, including the cricoid, thyroid and epiglottic, and two each of arytenoid, corniculate and cuneiform.Tissue Engineering: Generating tissue in vitro for clinical applications, such as replacing wounded tissues or impaired organs. The use of TISSUE SCAFFOLDING enables the generation of complex multi-layered tissues and tissue structures.Prostheses and Implants: Artificial substitutes for body parts, and materials inserted into tissue for functional, cosmetic, or therapeutic purposes. Prostheses can be functional, as in the case of artificial arms and legs, or cosmetic, as in the case of an artificial eye. Implants, all surgically inserted or grafted into the body, tend to be used therapeutically. IMPLANTS, EXPERIMENTAL is available for those used experimentally.Spinal Nerve Roots: Paired bundles of NERVE FIBERS entering and leaving the SPINAL CORD at each segment. The dorsal and ventral nerve roots join to form the mixed segmental spinal nerves. The dorsal roots are generally afferent, formed by the central projections of the spinal (dorsal root) ganglia sensory cells, and the ventral roots are efferent, comprising the axons of spinal motor and PREGANGLIONIC AUTONOMIC FIBERS.Osteoarthritis, Spine: A degenerative joint disease involving the SPINE. It is characterized by progressive deterioration of the spinal articular cartilage (CARTILAGE, ARTICULAR), usually with hardening of the subchondral bone and outgrowth of bone spurs (OSTEOPHYTE).Collagen: A polypeptide substance comprising about one third of the total protein in mammalian organisms. It is the main constituent of SKIN; CONNECTIVE TISSUE; and the organic substance of bones (BONE AND BONES) and teeth (TOOTH).Hexuronic Acids: Term used to designate tetrahydroxy aldehydic acids obtained by oxidation of hexose sugars, i.e. glucuronic acid, galacturonic acid, etc. Historically, the name hexuronic acid was originally given to ascorbic acid.Cellular Microenvironment: Local surroundings with which cells interact by processing various chemical and physical signals, and by contributing their own effects to this environment.Calcium Pyrophosphate: An inorganic pyrophosphate which affects calcium metabolism in mammals. Abnormalities in its metabolism occur in some human diseases, notably HYPOPHOSPHATASIA and pseudogout (CHONDROCALCINOSIS).Collagen Type X: A non-fibrillar collagen found primarily in terminally differentiated hypertrophic CHONDROCYTES. It is a homotrimer of three identical alpha1(X) subunits.Radiography: Examination of any part of the body for diagnostic purposes by means of X-RAYS or GAMMA RAYS, recording the image on a sensitized surface (such as photographic film).Prosthesis Implantation: Surgical insertion of a prosthesis.Traction: The pull on a limb or a part thereof. Skin traction (indirect traction) is applied by using a bandage to pull on the skin and fascia where light traction is required. Skeletal traction (direct traction), however, uses pins or wires inserted through bone and is attached to weights, pulleys, and ropes. (From Blauvelt & Nelson, A Manual of Orthopaedic Terminology, 5th ed)Hyaline Cartilage: A type of CARTILAGE characterized by a homogenous amorphous matrix containing predominately TYPE II COLLAGEN and ground substance. Hyaline cartilage is found in ARTICULAR CARTILAGE; COSTAL CARTILAGE; LARYNGEAL CARTILAGES; and the NASAL SEPTUM.Collagen Type I: The most common form of fibrillar collagen. It is a major constituent of bone (BONE AND BONES) and SKIN and consists of a heterotrimer of two alpha1(I) and one alpha2(I) chains.Cell Transplantation: Transference of cells within an individual, between individuals of the same species, or between individuals of different species.Cells, Cultured: Cells propagated in vitro in special media conducive to their growth. Cultured cells are used to study developmental, morphologic, metabolic, physiologic, and genetic processes, among others.Disease Models, Animal: Naturally occurring or experimentally induced animal diseases with pathological processes sufficiently similar to those of human diseases. They are used as study models for human diseases.Temporomandibular Joint Disc: A plate of fibrous tissue that divides the temporomandibular joint into an upper and lower cavity. The disc is attached to the articular capsule and moves forward with the condyle in free opening and protrusion. (Boucher's Clinical Dental Terminology, 4th ed, p92)Growth Differentiation Factor 5: A growth differentiation factor that plays a role in early CHONDROGENESIS and joint formation.Decorin: A small leucine-rich proteoglycan that interacts with FIBRILLAR COLLAGENS and modifies the EXTRACELLULAR MATRIX structure of CONNECTIVE TISSUE. Decorin has also been shown to play additional roles in the regulation of cellular responses to GROWTH FACTORS. The protein contains a single glycosaminoglycan chain and is similar in structure to BIGLYCAN.