Spinal Cord Injuries: Penetrating and non-penetrating injuries to the spinal cord resulting from traumatic external forces (e.g., WOUNDS, GUNSHOT; WHIPLASH INJURIES; etc.).Spinal Cord: A cylindrical column of tissue that lies within the vertebral canal. It is composed of WHITE MATTER and GRAY MATTER.Paraplegia: Severe or complete loss of motor function in the lower extremities and lower portions of the trunk. This condition is most often associated with SPINAL CORD DISEASES, although BRAIN DISEASES; PERIPHERAL NERVOUS SYSTEM DISEASES; NEUROMUSCULAR DISEASES; and MUSCULAR DISEASES may also cause bilateral leg weakness.Quadriplegia: Severe or complete loss of motor function in all four limbs which may result from BRAIN DISEASES; SPINAL CORD DISEASES; PERIPHERAL NERVOUS SYSTEM DISEASES; NEUROMUSCULAR DISEASES; or rarely MUSCULAR DISEASES. The locked-in syndrome is characterized by quadriplegia in combination with cranial muscle paralysis. Consciousness is spared and the only retained voluntary motor activity may be limited eye movements. This condition is usually caused by a lesion in the upper BRAIN STEM which injures the descending cortico-spinal and cortico-bulbar tracts.Spinal Cord Diseases: Pathologic conditions which feature SPINAL CORD damage or dysfunction, including disorders involving the meninges and perimeningeal spaces surrounding the spinal cord. Traumatic injuries, vascular diseases, infections, and inflammatory/autoimmune processes may affect the spinal cord.Recovery of Function: A partial or complete return to the normal or proper physiologic activity of an organ or part following disease or trauma.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.Cervical Vertebrae: The first seven VERTEBRAE of the SPINAL COLUMN, which correspond to the VERTEBRAE of the NECK.Nerve Regeneration: Renewal or physiological repair of damaged nerve tissue.Wounds and Injuries: Damage inflicted on the body as the direct or indirect result of an external force, with or without disruption of structural continuity.Autonomic Dysreflexia: A syndrome associated with damage to the spinal cord above the mid thoracic level (see SPINAL CORD INJURIES) characterized by a marked increase in the sympathetic response to minor stimuli such as bladder or rectal distention. Manifestations include HYPERTENSION; TACHYCARDIA (or reflex bradycardia); FEVER; FLUSHING; and HYPERHIDROSIS. Extreme hypertension may be associated with a STROKE. (From Adams et al., Principles of Neurology, 6th ed, pp538 and 1232; J Spinal Cord Med 1997;20(3):355-60)Spinal Cord Neoplasms: Benign and malignant neoplasms which occur within the substance of the spinal cord (intramedullary neoplasms) or in the space between the dura and spinal cord (intradural extramedullary neoplasms). The majority of intramedullary spinal tumors are primary CNS neoplasms including ASTROCYTOMA; EPENDYMOMA; and LIPOMA. Intramedullary neoplasms are often associated with SYRINGOMYELIA. The most frequent histologic types of intradural-extramedullary tumors are MENINGIOMA and NEUROFIBROMA.Spinal Cord Regeneration: Repair of the damaged neuron function after SPINAL CORD INJURY or SPINAL CORD DISEASES.Urinary Bladder, Neurogenic: Dysfunction of the URINARY BLADDER due to disease of the central or peripheral nervous system pathways involved in the control of URINATION. This is often associated with SPINAL CORD DISEASES, but may also be caused by BRAIN DISEASES or PERIPHERAL NERVE DISEASES.Spinal Cord Ischemia: Reduced blood flow to the spinal cord which is supplied by the anterior spinal artery and the paired posterior spinal arteries. This condition may be associated with ARTERIOSCLEROSIS, trauma, emboli, diseases of the aorta, and other disorders. Prolonged ischemia may lead to INFARCTION of spinal cord tissue.Thoracic Vertebrae: A group of twelve VERTEBRAE connected to the ribs that support the upper trunk region.Paralysis: A general term most often used to describe severe or complete loss of muscle strength due to motor system disease from the level of the cerebral cortex to the muscle fiber. This term may also occasionally refer to a loss of sensory function. (From Adams et al., Principles of Neurology, 6th ed, p45)Wheelchairs: Chairs mounted on wheels and designed to be propelled by the occupant.Locomotion: Movement or the ability to move from one place or another. It can refer to humans, vertebrate or invertebrate animals, and microorganisms.Contusions: Injuries resulting in hemorrhage, usually manifested in the skin.Injections, Spinal: Introduction of therapeutic agents into the spinal region using a needle and syringe.Spinal Injuries: Injuries involving the vertebral column.Rats, Sprague-Dawley: A strain of albino rat used widely for experimental purposes because of its calmness and ease of handling. It was developed by the Sprague-Dawley Animal Company.Electric Stimulation Therapy: Application of electric current in treatment without the generation of perceptible heat. It includes electric stimulation of nerves or muscles, passage of current into the body, or use of interrupted current of low intensity to raise the threshold of the skin to pain.Motor Neurons: Neurons which activate MUSCLE CELLS.Brain Injuries: Acute and chronic (see also BRAIN INJURIES, CHRONIC) injuries to the brain, including the cerebral hemispheres, CEREBELLUM, and BRAIN STEM. Clinical manifestations depend on the nature of injury. Diffuse trauma to the brain is frequently associated with DIFFUSE AXONAL INJURY or COMA, POST-TRAUMATIC. Localized injuries may be associated with NEUROBEHAVIORAL MANIFESTATIONS; HEMIPARESIS, or other focal neurologic deficits.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.Axons: Nerve fibers that are capable of rapidly conducting impulses away from the neuron cell body.Injury Severity Score: An anatomic severity scale based on the Abbreviated Injury Scale (AIS) and developed specifically to score multiple traumatic injuries. It has been used as a predictor of mortality.Pressure Ulcer: An ulceration caused by prolonged pressure on the SKIN and TISSUES when one stays in one position for a long period of time, such as lying in bed. The bony areas of the body are the most frequently affected sites which become ischemic (ISCHEMIA) under sustained and constant pressure.Muscle Spasticity: A form of muscle hypertonia associated with upper MOTOR NEURON DISEASE. Resistance to passive stretch of a spastic muscle results in minimal initial resistance (a "free interval") followed by an incremental increase in muscle tone. Tone increases in proportion to the velocity of stretch. Spasticity is usually accompanied by HYPERREFLEXIA and variable degrees of MUSCLE WEAKNESS. (From Adams et al., Principles of Neurology, 6th ed, p54)Myelitis: Inflammation of the spinal cord. Relatively common etiologies include infections; AUTOIMMUNE DISEASES; SPINAL CORD; and ischemia (see also SPINAL CORD VASCULAR DISEASES). Clinical features generally include weakness, sensory loss, localized pain, incontinence, and other signs of autonomic dysfunction.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.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.Athletic Injuries: Injuries incurred during participation in competitive or non-competitive sports.Motor Activity: The physical activity of a human or an animal as a behavioral phenomenon.Spinal Nerves: The 31 paired peripheral nerves formed by the union of the dorsal and ventral spinal roots from each spinal cord segment. The spinal nerve plexuses and the spinal roots are also included.Time Factors: Elements of limited time intervals, contributing to particular results or situations.Neuralgia: Intense or aching pain that occurs along the course or distribution of a peripheral or cranial nerve.Electromyography: Recording of the changes in electric potential of muscle by means of surface or needle electrodes.Pyramidal Tracts: Fibers that arise from cells within the cerebral cortex, pass through the medullary pyramid, and descend in the spinal cord. Many authorities say the pyramidal tracts include both the corticospinal and corticobulbar tracts.Cordotomy: Any operation on the spinal cord. (Stedman, 26th ed)Chondroitin ABC Lyase: An enzyme that catalyzes the eliminative degradation of polysaccharides containing 1,4-beta-D-hexosaminyl and 1,3-beta-D-glucuronosyl or 1,3-alpha-L-iduronosyl linkages to disaccharides containing 4-deoxy-beta-D-gluc-4-enuronosyl groups. (Enzyme Nomenclature, 1992)Pain: An unpleasant sensation induced by noxious stimuli which are detected by NERVE ENDINGS of NOCICEPTIVE NEURONS.Reperfusion Injury: Adverse functional, metabolic, or structural changes in ischemic tissues resulting from the restoration of blood flow to the tissue (REPERFUSION), including swelling; HEMORRHAGE; NECROSIS; and damage from FREE RADICALS. The most common instance is MYOCARDIAL REPERFUSION INJURY.Lumbosacral Region: Region of the back including the LUMBAR VERTEBRAE, SACRUM, and nearby structures.Spasm: An involuntary contraction of a muscle or group of muscles. Spasms may involve SKELETAL MUSCLE or SMOOTH MUSCLE.Reflex: An involuntary movement or exercise of function in a part, excited in response to a stimulus applied to the periphery and transmitted to the brain or spinal cord.Urinary Catheterization: Passage of a CATHETER into the URINARY BLADDER or kidney.Posterior Horn Cells: Neurons in the SPINAL CORD DORSAL HORN whose cell bodies and processes are confined entirely to the CENTRAL NERVOUS SYSTEM. They receive collateral or direct terminations of dorsal root fibers. They send their axons either directly to ANTERIOR HORN CELLS or to the WHITE MATTER ascending and descending longitudinal fibers.Anterior Horn Cells: MOTOR NEURONS in the anterior (ventral) horn of the SPINAL CORD which project to SKELETAL MUSCLES.Neck Injuries: General or unspecified injuries to the neck. It includes injuries to the skin, muscles, and other soft tissues of the neck.Neurons: The basic cellular units of nervous tissue. Each neuron consists of a body, an axon, and dendrites. Their purpose is to receive, conduct, and transmit impulses in the NERVOUS SYSTEM.Hindlimb: Either of two extremities of four-footed non-primate land animals. It usually consists of a FEMUR; TIBIA; and FIBULA; tarsals; METATARSALS; and TOES. (From Storer et al., General Zoology, 6th ed, p73)Gait Disorders, Neurologic: Gait abnormalities that are a manifestation of nervous system dysfunction. These conditions may be caused by a wide variety of disorders which affect motor control, sensory feedback, and muscle strength including: CENTRAL NERVOUS SYSTEM DISEASES; PERIPHERAL NERVOUS SYSTEM DISEASES; NEUROMUSCULAR DISEASES; or MUSCULAR DISEASES.Ganglia, Spinal: Sensory ganglia located on the dorsal spinal roots within the vertebral column. The spinal ganglion cells are pseudounipolar. The single primary branch bifurcates sending a peripheral process to carry sensory information from the periphery and a central branch which relays that information to the spinal cord or brain.Spinal Canal: The cavity within the SPINAL COLUMN through which the SPINAL CORD passes.Myelin Sheath: The lipid-rich sheath surrounding AXONS in both the CENTRAL NERVOUS SYSTEMS and PERIPHERAL NERVOUS SYSTEM. The myelin sheath is an electrical insulator and allows faster and more energetically efficient conduction of impulses. The sheath is formed by the cell membranes of glial cells (SCHWANN CELLS in the peripheral and OLIGODENDROGLIA in the central nervous system). Deterioration of the sheath in DEMYELINATING DISEASES is a serious clinical problem.Spinal NeoplasmsOligodendroglia: A class of large neuroglial (macroglial) cells in the central nervous system. Oligodendroglia may be called interfascicular, perivascular, or perineuronal (not the same as SATELLITE CELLS, PERINEURONAL of GANGLIA) according to their location. They form the insulating MYELIN SHEATH of axons in the central nervous system.Neuronal Plasticity: The capacity of the NERVOUS SYSTEM to change its reactivity as the result of successive activations.Anesthesia, Spinal: Procedure in which an anesthetic is injected directly into the spinal cord.Evoked Potentials, Somatosensory: The electric response evoked in the CEREBRAL CORTEX by stimulation along AFFERENT PATHWAYS from PERIPHERAL NERVES to CEREBRUM.Neuroprotective Agents: Drugs intended to prevent damage to the brain or spinal cord from ischemia, stroke, convulsions, or trauma. Some must be administered before the event, but others may be effective for some time after. They act by a variety of mechanisms, but often directly or indirectly minimize the damage produced by endogenous excitatory amino acids.Electric Stimulation: Use of electric potential or currents to elicit biological responses.Respiratory Paralysis: Complete or severe weakness of the muscles of respiration. This condition may be associated with MOTOR NEURON DISEASES; PERIPHERAL NERVE DISEASES; NEUROMUSCULAR JUNCTION DISEASES; SPINAL CORD DISEASES; injury to the PHRENIC NERVE; and other disorders.Hyperalgesia: An increased sensation of pain or discomfort produced by mimimally noxious stimuli due to damage to soft tissue containing NOCICEPTORS or injury to a peripheral nerve.Neuroglia: The non-neuronal cells of the nervous system. They not only provide physical support, but also respond to injury, regulate the ionic and chemical composition of the extracellular milieu, participate in the BLOOD-BRAIN BARRIER and BLOOD-RETINAL BARRIER, form the myelin insulation of nervous pathways, guide neuronal migration during development, and exchange metabolites with neurons. Neuroglia have high-affinity transmitter uptake systems, voltage-dependent and transmitter-gated ion channels, and can release transmitters, but their role in signaling (as in many other functions) is unclear.Spinal DiseasesAstrocytes: A class of large neuroglial (macroglial) cells in the central nervous system - the largest and most numerous neuroglial cells in the brain and spinal cord. Astrocytes (from "star" cells) are irregularly shaped with many long processes, including those with "end feet" which form the glial (limiting) membrane and directly and indirectly contribute to the BLOOD-BRAIN BARRIER. They regulate the extracellular ionic and chemical environment, and "reactive astrocytes" (along with MICROGLIA) respond to injury.Glial Fibrillary Acidic Protein: An intermediate filament protein found only in glial cells or cells of glial origin. MW 51,000.Urinary Bladder: A musculomembranous sac along the URINARY TRACT. URINE flows from the KIDNEYS into the bladder via the ureters (URETER), and is held there until URINATION.Umbilical Cord: The flexible rope-like structure that connects a developing FETUS to the PLACENTA in mammals. The cord contains blood vessels which carry oxygen and nutrients from the mother to the fetus and waste products away from the fetus.Walking: An activity in which the body advances at a slow to moderate pace by moving the feet in a coordinated fashion. This includes recreational walking, walking for fitness, and competitive race-walking.Neurologic Examination: Assessment of sensory and motor responses and reflexes that is used to determine impairment of the nervous system.Myelography: X-ray visualization of the spinal cord following injection of contrast medium into the spinal arachnoid space.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)Rehabilitation Centers: Facilities which provide programs for rehabilitating the mentally or physically disabled individuals.Pain Measurement: Scales, questionnaires, tests, and other methods used to assess pain severity and duration in patients or experimental animals to aid in diagnosis, therapy, and physiological studies.Spinal Stenosis: Narrowing of the spinal canal.Ossification, Heterotopic: The development of bony substance in normally soft structures.Muscle, Skeletal: A subtype of striated muscle, attached by TENDONS to the SKELETON. Skeletal muscles are innervated and their movement can be consciously controlled. They are also called voluntary muscles.Immunohistochemistry: Histochemical localization of immunoreactive substances using labeled antibodies as reagents.Gliosis: The production of a dense fibrous network of neuroglia; includes astrocytosis, which is a proliferation of astrocytes in the area of a degenerative lesion.Physical Stimulation: Act of eliciting a response from a person or organism through physical contact.Analysis of Variance: A statistical technique that isolates and assesses the contributions of categorical independent variables to variation in the mean of a continuous dependent variable.Urodynamics: The mechanical laws of fluid dynamics as they apply to urine transport.Afferent Pathways: Nerve structures through which impulses are conducted from a peripheral part toward a nerve center.Trauma Severity Indices: Systems for assessing, classifying, and coding injuries. These systems are used in medical records, surveillance systems, and state and national registries to aid in the collection and reporting of trauma.Reflex, Abnormal: An abnormal response to a stimulus applied to the sensory components of the nervous system. This may take the form of increased, decreased, or absent reflexes.Sensation: The process in which specialized SENSORY RECEPTOR CELLS transduce peripheral stimuli (physical or chemical) into NERVE IMPULSES which are then transmitted to the various sensory centers in the CENTRAL NERVOUS SYSTEM.Treatment Outcome: Evaluation undertaken to assess the results or consequences of management and procedures used in combating disease in order to determine the efficacy, effectiveness, safety, and practicability of these interventions in individual cases or series.Microglia: The third type of glial cell, along with astrocytes and oligodendrocytes (which together form the macroglia). Microglia vary in appearance depending on developmental stage, functional state, and anatomical location; subtype terms include ramified, perivascular, ameboid, resting, and activated. Microglia clearly are capable of phagocytosis and play an important role in a wide spectrum of neuropathologies. They have also been suggested to act in several other roles including in secretion (e.g., of cytokines and neural growth factors), in immunological processing (e.g., antigen presentation), and in central nervous system development and remodeling.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.Cicatrix: The fibrous tissue that replaces normal tissue during the process of WOUND HEALING.Forelimb: A front limb of a quadruped. (The Random House College Dictionary, 1980)Hematoma, Epidural, Spinal: A rare epidural hematoma in the spinal epidural space, usually due to a vascular malformation (CENTRAL NERVOUS SYSTEM VASCULAR MALFORMATIONS) or TRAUMA. Spontaneous spinal epidural hematoma is a neurologic emergency due to a rapidly evolving compressive MYELOPATHY.Epidural Space: Space between the dura mater and the walls of the vertebral canal.H-Reflex: A monosynaptic reflex elicited by stimulating a nerve, particularly the tibial nerve, with an electric shock.Rats, Wistar: A strain of albino rat developed at the Wistar Institute that has spread widely at other institutions. This has markedly diluted the original strain.Leg Injuries: General or unspecified injuries involving the leg.Efferent Pathways: Nerve structures through which impulses are conducted from a nerve center toward a peripheral site. Such impulses are conducted via efferent neurons (NEURONS, EFFERENT), such as MOTOR NEURONS, autonomic neurons, and hypophyseal neurons.Spinal Cord Stimulation: Application of electric current to the spine for treatment of a variety of conditions involving innervation from the spinal cord.Urethra: A tube that transports URINE from the URINARY BLADDER to the outside of the body in both the sexes. It also has a reproductive function in the male by providing a passage for SPERM.Chronic Disease: Diseases which have one or more of the following characteristics: they are permanent, leave residual disability, are caused by nonreversible pathological alteration, require special training of the patient for rehabilitation, or may be expected to require a long period of supervision, observation, or care. (Dictionary of Health Services Management, 2d ed)Accidents, Traffic: Accidents on streets, roads, and highways involving drivers, passengers, pedestrians, or vehicles. Traffic accidents refer to AUTOMOBILES (passenger cars, buses, and trucks), BICYCLING, and MOTORCYCLES but not OFF-ROAD MOTOR VEHICLES; RAILROADS nor snowmobiles.Urination: Discharge of URINE, liquid waste processed by the KIDNEY, from the body.Lumbar Vertebrae: VERTEBRAE in the region of the lower BACK below the THORACIC VERTEBRAE and above the SACRAL VERTEBRAE.Lung Injury: Damage to any compartment of the lung caused by physical, chemical, or biological agents which characteristically elicit inflammatory reaction. These inflammatory reactions can either be acute and dominated by NEUTROPHILS, or chronic and dominated by LYMPHOCYTES and MACROPHAGES.Spine: The spinal or vertebral column.Peripheral Nerve Injuries: Injuries to the PERIPHERAL NERVES.Evoked Potentials, Motor: The electrical response evoked in a muscle or motor nerve by electrical or magnetic stimulation. Common methods of stimulation are by transcranial electrical and TRANSCRANIAL MAGNETIC STIMULATION. It is often used for monitoring during neurosurgery.Mice, Inbred C57BLPhrenic Nerve: The motor nerve of the diaphragm. The phrenic nerve fibers originate in the cervical spinal column (mostly C4) and travel through the cervical plexus to the diaphragm.Exercise Therapy: A regimen or plan of physical activities designed and prescribed for specific therapeutic goals. Its purpose is to restore normal musculoskeletal function or to reduce pain caused by diseases or injuries.Disability Evaluation: Determination of the degree of a physical, mental, or emotional handicap. The diagnosis is applied to legal qualification for benefits and income under disability insurance and to eligibility for Social Security and workmen's compensation benefits.Myelin Proteins: MYELIN-specific proteins that play a structural or regulatory role in the genesis and maintenance of the lamellar MYELIN SHEATH structure.Behavior, Animal: The observable response an animal makes to any situation.Neurons, Afferent: Neurons which conduct NERVE IMPULSES to the CENTRAL NERVOUS SYSTEM.Ejaculation: The emission of SEMEN to the exterior, resulting from the contraction of muscles surrounding the male internal urogenital ducts.Activities of Daily Living: The performance of the basic activities of self care, such as dressing, ambulation, or eating.Syringomyelia: Longitudinal cavities in the spinal cord, most often in the cervical region, which may extend for multiple spinal levels. The cavities are lined by dense, gliogenous tissue and may be associated with SPINAL CORD NEOPLASMS; spinal cord traumatic injuries; and vascular malformations. Syringomyelia is marked clinically by pain and PARESTHESIA, muscular atrophy of the hands, and analgesia with thermoanesthesia of the hands and arms, but with the tactile sense preserved (sensory dissociation). Lower extremity spasticity and incontinence may also develop. (From Adams et al., Principles of Neurology, 6th ed, p1269)Muscle Relaxants, Central: A heterogeneous group of drugs used to produce muscle relaxation, excepting the neuromuscular blocking agents. They have their primary clinical and therapeutic uses in the treatment of muscle spasm and immobility associated with strains, sprains, and injuries of the back and, to a lesser degree, injuries to the neck. They have been used also for the treatment of a variety of clinical conditions that have in common only the presence of skeletal muscle hyperactivity, for example, the muscle spasms that can occur in MULTIPLE SCLEROSIS. (From Smith and Reynard, Textbook of Pharmacology, 1991, p358)Physical Therapy Modalities: Therapeutic modalities frequently used in PHYSICAL THERAPY SPECIALTY by PHYSICAL THERAPISTS or physiotherapists to promote, maintain, or restore the physical and physiological well-being of an individual.Wounds, Stab: Penetrating wounds caused by a pointed object.Movement: The act, process, or result of passing from one place or position to another. It differs from LOCOMOTION in that locomotion is restricted to the passing of the whole body from one place to another, while movement encompasses both locomotion but also a change of the position of the whole body or any of its parts. Movement may be used with reference to humans, vertebrate and invertebrate animals, and microorganisms. Differentiate also from MOTOR ACTIVITY, movement associated with behavior.Tibial Nerve: The medial terminal branch of the sciatic nerve. The tibial nerve fibers originate in lumbar and sacral spinal segments (L4 to S2). They supply motor and sensory innervation to parts of the calf and foot.Orthotic Devices: Apparatus used to support, align, prevent, or correct deformities or to improve the function of movable parts of the body.Nerve Fibers, Myelinated: A class of nerve fibers as defined by their structure, specifically the nerve sheath arrangement. The AXONS of the myelinated nerve fibers are completely encased in a MYELIN SHEATH. They are fibers of relatively large and varied diameters. Their NEURAL CONDUCTION rates are faster than those of the unmyelinated nerve fibers (NERVE FIBERS, UNMYELINATED). Myelinated nerve fibers are present in somatic and autonomic nerves.Decompression, Surgical: A surgical operation for the relief of pressure in a body compartment or on a body part. (From Dorland, 28th ed)Nociceptors: Peripheral AFFERENT NEURONS which are sensitive to injuries or pain, usually caused by extreme thermal exposures, mechanical forces, or other noxious stimuli. Their cell bodies reside in the DORSAL ROOT GANGLIA. Their peripheral terminals (NERVE ENDINGS) innervate target tissues and transduce noxious stimuli via axons to the CENTRAL NERVOUS SYSTEM.Gait: Manner or style of walking.Peripheral Nerves: The nerves outside of the brain and spinal cord, including the autonomic, cranial, and spinal nerves. Peripheral nerves contain non-neuronal cells and connective tissue as well as axons. The connective tissue layers include, from the outside to the inside, the epineurium, the perineurium, and the endoneurium.Retrospective Studies: Studies used to test etiologic hypotheses in which inferences about an exposure to putative causal factors are derived from data relating to characteristics of persons under study or to events or experiences in their past. The essential feature is that some of the persons under study have the disease or outcome of interest and their characteristics are compared with those of unaffected persons.Ergometry: Any method of measuring the amount of work done by an organism, usually during PHYSICAL EXERTION. Ergometry also includes measures of power. Some instruments used in these determinations include the hand crank and the bicycle ergometer.Pain Threshold: Amount of stimulation required before the sensation of pain is experienced.Posture: The position or attitude of the body.Cats: The domestic cat, Felis catus, of the carnivore family FELIDAE, comprising over 30 different breeds. The domestic cat is descended primarily from the wild cat of Africa and extreme southwestern Asia. Though probably present in towns in Palestine as long ago as 7000 years, actual domestication occurred in Egypt about 4000 years ago. (From Walker's Mammals of the World, 6th ed, p801)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.Eye Injuries: Damage or trauma inflicted to the eye by external means. The concept includes both surface injuries and intraocular injuries.Muscular Atrophy, Spinal: A group of disorders marked by progressive degeneration of motor neurons in the spinal cord resulting in weakness and muscular atrophy, usually without evidence of injury to the corticospinal tracts. Diseases in this category include Werdnig-Hoffmann disease and later onset SPINAL MUSCULAR ATROPHIES OF CHILDHOOD, most of which are hereditary. (Adams et al., Principles of Neurology, 6th ed, p1089)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.Methylprednisolone: A PREDNISOLONE derivative with similar anti-inflammatory action.Central Nervous System: The main information-processing organs of the nervous system, consisting of the brain, spinal cord, and meninges.Robotics: The application of electronic, computerized control systems to mechanical devices designed to perform human functions. Formerly restricted to industry, but nowadays applied to artificial organs controlled by bionic (bioelectronic) devices, like automated insulin pumps and other prostheses.Biomechanical Phenomena: The properties, processes, and behavior of biological systems under the action of mechanical forces.Cell Transplantation: Transference of cells within an individual, between individuals of the same species, or between individuals of different species.Thoracic Injuries: General or unspecified injuries to the chest area.Movement Disorders: Syndromes which feature DYSKINESIAS as a cardinal manifestation of the disease process. Included in this category are degenerative, hereditary, post-infectious, medication-induced, post-inflammatory, and post-traumatic conditions.Urinary Bladder Diseases: Pathological processes of the URINARY BLADDER.Stem Cell Transplantation: The transfer of STEM CELLS from one individual to another within the same species (TRANSPLANTATION, HOMOLOGOUS) or between species (XENOTRANSPLANTATION), or transfer within the same individual (TRANSPLANTATION, AUTOLOGOUS). The source and location of the stem cells determines their potency or pluripotency to differentiate into various cell types.Sciatic Nerve: A nerve which originates in the lumbar and sacral spinal cord (L4 to S3) and supplies motor and sensory innervation to the lower extremity. The sciatic nerve, which is the main continuation of the sacral plexus, is the largest nerve in the body. It has two major branches, the TIBIAL NERVE and the PERONEAL NERVE.Spinal Fractures: Broken bones in the vertebral column.Acute Lung Injury: A condition of lung damage that is characterized by bilateral pulmonary infiltrates (PULMONARY EDEMA) rich in NEUTROPHILS, and in the absence of clinical HEART FAILURE. This can represent a spectrum of pulmonary lesions, endothelial and epithelial, due to numerous factors (physical, chemical, or biological).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.Wallerian Degeneration: Degeneration of distal aspects of a nerve axon following injury to the cell body or proximal portion of the axon. The process is characterized by fragmentation of the axon and its MYELIN SHEATH.Electrodes, Implanted: Surgically placed electric conductors through which ELECTRIC STIMULATION is delivered to or electrical activity is recorded from a specific point inside the body.Interneurons: Most generally any NEURONS which are not motor or sensory. Interneurons may also refer to neurons whose AXONS remain within a particular brain region in contrast to projection neurons, which have axons projecting to other brain regions.Functional Laterality: Behavioral manifestations of cerebral dominance in which there is preferential use and superior functioning of either the left or the right side, as in the preferred use of the right hand or right foot.Ependyma: A thin membrane that lines the CEREBRAL VENTRICLES and the central canal of the SPINAL CORD.Craniocerebral Trauma: Traumatic injuries involving the cranium and intracranial structures (i.e., BRAIN; CRANIAL NERVES; MENINGES; and other structures). Injuries may be classified by whether or not the skull is penetrated (i.e., penetrating vs. nonpenetrating) or whether there is an associated hemorrhage.Veterans: Former members of the armed services.Leg: The inferior part of the lower extremity between the KNEE and the ANKLE.Neural Stem Cells: Self-renewing cells that generate the main phenotypes of the nervous system in both the embryo and adult. Neural stem cells are precursors to both NEURONS and NEUROGLIA.Nerve Tissue ProteinsNeural Conduction: The propagation of the NERVE IMPULSE along the nerve away from the site of an excitation stimulus.Ischium: One of three bones that make up the coxal bone of the pelvic girdle. In tetrapods, it is the part of the pelvis that projects backward on the ventral side, and in primates, it bears the weight of the sitting animal.Pain, Intractable: Persistent pain that is refractory to some or all forms of treatment.Neural Pathways: Neural tracts connecting one part of the nervous system with another.Methylprednisolone Hemisuccinate: A water-soluble ester of METHYLPREDNISOLONE used for cardiac, allergic, and hypoxic emergencies.Animals, Newborn: Refers to animals in the period of time just after birth.Nerve Degeneration: Loss of functional activity and trophic degeneration of nerve axons and their terminal arborizations following the destruction of their cells of origin or interruption of their continuity with these cells. The pathology is characteristic of neurodegenerative diseases. Often the process of nerve degeneration is studied in research on neuroanatomical localization and correlation of the neurophysiology of neural pathways.Neural Prostheses: Medical devices which substitute for a nervous system function by electrically stimulating the nerves directly and monitoring the response to the electrical stimulation.Abdominal Injuries: General or unspecified injuries involving organs in the abdominal cavity.Analgesics: Compounds capable of relieving pain without the loss of CONSCIOUSNESS.Stilbamidines: STILBENES with AMIDINES attached.Wounds, Nonpenetrating: Injuries caused by impact with a blunt object where there is no penetration of the skin.DislocationsAccidentsHyperesthesia: Increased sensitivity to cutaneous stimulation due to a diminished threshold or an increased response to stimuli.Cauda Equina: The lower part of the SPINAL CORD consisting of the lumbar, sacral, and coccygeal nerve roots.Acute Kidney Injury: Abrupt reduction in kidney function. Acute kidney injury encompasses the entire spectrum of the syndrome including acute kidney failure; ACUTE KIDNEY TUBULAR NECROSIS; and other less severe conditions.Man-Machine Systems: A system in which the functions of the man and the machine are interrelated and necessary for the operation of the system.Arm Injuries: General or unspecified injuries involving the arm.Neurotrophin 3: A neurotrophic factor involved in regulating the survival of visceral and proprioceptive sensory neurons. It is closely homologous to nerve growth factor beta and BRAIN-DERIVED NEUROTROPHIC FACTOR.GAP-43 Protein: A nervous tissue specific protein which is highly expressed in NEURONS during development and NERVE REGENERATION. It has been implicated in neurite outgrowth, long-term potentiation, SIGNAL TRANSDUCTION, and NEUROTRANSMITTER release. (From Neurotoxicology 1994;15(1):41-7) It is also a substrate of PROTEIN KINASE C.Cell Count: The number of CELLS of a specific kind, usually measured per unit volume or area of sample.Urinary Bladder Calculi: Stones in the URINARY BLADDER; also known as vesical calculi, bladder stones, or cystoliths.Schwann Cells: Neuroglial cells of the peripheral nervous system which form the insulating myelin sheaths of peripheral axons.Evoked Potentials: Electrical responses recorded from nerve, muscle, SENSORY RECEPTOR, or area of the CENTRAL NERVOUS SYSTEM following stimulation. They range from less than a microvolt to several microvolts. The evoked potential can be auditory (EVOKED POTENTIALS, AUDITORY), somatosensory (EVOKED POTENTIALS, SOMATOSENSORY), visual (EVOKED POTENTIALS, VISUAL), or motor (EVOKED POTENTIALS, MOTOR), or other modalities that have been reported.