D
DEEP BRAIN STIMULATION - A tremor control therapy for patients with Parkinson's Disease or essential tremors who do not respond effectively to medications. It is a surgical reversible procedure that involves implanting a device to deliver mild electrical stimulation to block the brain signals that cause tremors.
DEMINERALIZED BONE - Bone tissue which has been depleted of its minerals; e.g., calcium and phosphorous.
DENDRITE - A nerve cell process that transmits impulses toward the cell body.
DEPRESSED SKULL FRACTURE - A break in the bones of the head in which some bone is pushed inward, possibly pushing on or cutting into the brain.
DIABETES INSIPIDUS - Excretion of large amounts of urine of low specific gravity. The inability to concentrate urine.
DIFFUSE AXONAL INJURY - Damage to the axons of many nerve cells that lie in different parts of the brain.
DIFFUSE BRAIN INJURY - Damage to the brain that can affect many parts of the brain, often in a subtle fashion; examples include diffused axonal injury and inadequate blood flow.
DIPHENYLHYDANTOIN - Dilantin; a medication used to control seizures.
DIPLOPIA - Double vision usually due to weakness or paralysis of one or more of the extraocular muscles.
DISC - The intervertebral disc; cartilaginous cushion found between the vertebrae of the spinal column. It may bulge beyond the vertebral body and compress the nearby nerve root causing pain. The terms "slipped disc," "ruptured disc," and "herniated disc" are often used interchangeably even though there are subtle differences.
DISC DEGENERATION - The loss of the structural and functional integrity of the disc.
DISCECTOMY - Surgical removal of part or all of an intervertebral disc.
DISTAL - Situated away from the center of the body.
DOME - The round balloon-like portion of the aneurysm which usually arises from the artery from a smaller portion called the neck of the aneurysm.
DOPPLER - A noninvasive study which uses sound waves to show the flow in a blood vessel and can be used to determine the degree of narrowing (percent stenosis) of the vessel. A wand is placed on the skin over the vessel to be imaged. This study has no risks and is not painful.
DURA - See dura mater below.
DURA MATER - A tough fibrous membrane which covers the brain and spinal cord, but is separated from them by a small space.
DURAL - Pertaining to the dura.
DYSESTHESIA - A condition in which a disagreeable sensation is produced by ordinary touch, temperature, or movement.
DYSPHASIA - Difficulty in the use of language due to a brain lesion without mental impairment.
DYSTONIA MUSCULORM DEFORMANS - An affliction occurring, especially in children, marked by muscular contractions producing distortions of the spin and hips.
E
EDEMA - An excessive accumulation of fluid, generally in the extracellular area.
ELECTROENCEPHALOGRAPHY (EEG) - The study of the electrical currents set up by brain actions; the record made is called an electroencephalogram.
ELECTROMYOGRAPHY (EMG) - A method of recording the electrical currents generated in a muscle during its contraction.
ENCEPHALOCELE - Protrusion of the brain through a cranial fissure.
ENDARTERECTOMY - Removal of fatty or cholesterol plaques and calcified deposits from the internal wall of an artery.
ENDOCRINE GLAND - A gland which furnishes an internal secretion, usually having an effect on another organ.
ENDOCRINOPATHY - Any disease due to abnormality of quantity or quality in one or more of the internal glandular secretions.
ENDOGENOUS - Arising within or derived from the body.
ENDOSCOPE - A medical device for viewing internal portions of the body. It is usually comprised of fiber optic tubes and video display instruments.
ENDOSCOPY - Inspection of internal body structures or cavities using an endoscope.
EPENDYMA - The membrane lining the cerebral ventricles of the brain and central canal of the spinal cord.
EPENDYMOMA - A growth in the brain or spinal cord arising from ependymal tissue.
EPIDURAL - Immediately outside the dura mater. Same as extradural.
EPIDURAL HEMATOMA - A blood clot between the dura mater and the inside of the skull.
EPILEPSY - Disorder characterized by abnormal electrical discharges in the brain, causing abnormal sensation, movement, or level of consciousness.
EXCISION - Removal by cutting away material.
EXTRADURAL - On the outer side of the dura mater.
EXOGENOUS - Originating outside of the body.
F
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.
FALX (CEREBRI) - An extension of dura between the right and left hemispheres of the brain.
FATIGUE FRACTURE - A fracture that occurs in bone or in other materials as a result of repeated stress as opposed to a single injury.
FENESTRATION OF CYST - Surgical creation of window-like opening.
FIBROSIS - The replacement of normal tissue with scar tissue.
FISSURE - A groove or natural division; deep furrow in the brain.
FONTANELLE - Normal openings in the skull of infants; the largest of these is the anterior fontanel or "soft spot" in the middle of the head.
FOOD AND DRUG ADMINISTRATION (FDA) - The federal government agency that has regulatory authority over the manufacture, distribution, and labeling of drugs, medical devices, and foods.
FORAMEN - A natural opening or passage in bone.
FORAMINOTOMY - Surgical opening or enlargement of the bony opening traversed by a nerve root as it leaves the spinal canal.
FRACTURE - A disruption of the normal continuity of bone.
FUNCTIONAL STEREOTACTIC NEUROSURGERY - Surgery intended to improve the function of the central nervous system. A stereotactic head frame is used along with imaging techniques to map the brain and localize the surgical target.
FUSIFORM ANEURYSM - A sausage-like enlargement of the vessel.
FUSION - Union or healing of bone. See arthrodesis.