Medical/Neurosurgical Glossary
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Dandy Operation – A surgical operation for facial pain, the glossopharyngeal nerve is cut within the skull.

David Disease – Also known as Pott disease, this is from damage to a vertebral bone from tuberculosis.

Debridement – The surgical removal of foreign material or dead, damaged, or infected tissue from a wound or burn.

Decompression Sickness – Also known as caisson disease, this involves the development of small bubbles in the arteries and veins.  It is seen in SCUBA divers who ascend too rapidly after a deep or long dive.  It was first reported in bridge workers who used pressurized caissons, or boxes, to build the bridge supports.

Deductible – Patients are often required to pay a certain amount of money each year for medical services before the insurance policy will pay for any treatments. This amount is called the deductible. For example, a patient may have to pay the first $500 of costs.

Deep – A structure that is below another, or closer to the center of the body, is said to be deeper.

Defendant – An insurance company or an employer defending itself against a claim brought by a plaintiff or an applicant.

Delayed Union – When a spinal fusion is performed during a surgical procedure, the goal is to establish a solid bone union. A delayed union refers to slower than expected healing between levels of the spine. If the spinal levels that have been fused never heal into solid bone, the result is called a pseudarthrosis or non-union. 

Deletion Syndrome – Any of a number of genetic problems, or birth defects, where a portion of the DNA is lost.  The syndromes are titled with the number of the damaged chromosome and the letter p or q, to indicate the loss of the long end of the chromosome or the short end respectively.

Dens – This bone is part of the second spinal vertebra (C2), the axis. It is a small bone peg that protrudes upward from C2.

De Quervain Disease – Inflammation of the tendon sheath (between the tendons of the abductor pollicis longus and the extensor pollicis brevis) behind the thumb causes pain with certain movements.  This is a very painful problem caused by overuse but is easily treated with injections, anti-inflammatory medications or surgery.

Derifield leg check – Test to detect pelvic dysfunction by measuring leg length in a prone (face-down) position. Measurements are obtained with the legs straight and with the knees bent. Leg checks are used by chiropractic activator practitioners and others who correct pelvic "imbalances."

DEU 100 form - One of two forms needed with every QME report (click here for the form).

DEU 101 form - The other of the two forms needed with every QME report (click here for the form).

Disability Evaluation Unit (DEU) - a California state office which calculates disability ratings based upon medical reports.

Diagnosis – Commonly abbreviated as “Dx,” this is the process of identifying a disease by its signs, symptoms, and laboratory findings.

Diabetes Insipidus – This is an uncommon disease where there is an abnormality of a hormone called anti-diuretic hormone (ADH).  Too much urine is produced and the blood sodium can become dangerously high.  It is associated with head injuries and other brain diseases.

Diabetes Mellitus (Sugar Diabetes) – A common disease where there is too much sugar in the blood.  This can be treated with diet, pills or insulin shots.  Untreated it causes permanent damage to the blood vessels and nerves.  Untreated it causes heart attacks and strokes.

Diabetic Foot Syndrome – Vascular and neurologic problems caused by diabetes frequently damage the foot and occasionally result in the death of the foot.  Amputation of the foot in a diabetic is not uncommon.

Dilate – To relax or expand a structure. 

Dimple Sign – Habitual crossing of the legs can cause a dimple or dent in the area around the knee.  This is associated with damage to the peroneal nerve and weakness of the foot.

Directional non-force technique (DNFT) – Method of diagnosing and correcting subluxations by applying thumb pressure to the spine and checking leg length, which supposedly changes when correction is made.

Disability Insurance – This is an insurance policy that pays a person when they are unable to work and which replaces some of the lost income.

Disability Rating - a numeric percentage (from 1% to 100%) that reflects an injured worker's loss of ability to compete in the labor market; the percent of jobs he/she can no longer do; applies only to the California state system.

Disc – This refers to any flat, round structure.

Disc (Intervertebral) – Intervertebral discs are soft tissue structures that are between the vertebral bones of the spine. They act as cushions but are easily damaged.

Disc Degeneration – This is the loss of the structural and functional integrity of the disc.  It is a wear and tear process.  Discs tend to degenerate more with each passing year.

Disc Disease – This is any problem which affects the intervertebral disc.  It may be due to an injury or to wear and tear (arthritis).

Disc Herniation, Prolapse or Slip – These are a group of terms that mean that a disc has become damaged and is moved out of its normal position.  It may, when damaged, pinch a nerve.  The disc damage can cause back pain and the nerve damage can cause arm or leg pain.

Discectomy – The surgical removal of part or all of an intervertebral disc.

Dispute - any disagreement between the insurance company and the injured worker in a workers' compensation case.

Disseminated Intravascular Coagulation Syndrome (DIC) – In serious diseases and following severe injuries, the blood can clot excessively or not enough.  This is an ominous sign and is often fatal.

Distal –This describes the position of one body part compared to another, the more distal part is farther away from the center of the body.

Distraction – Excessive space between structures such as vertebral bones.  It is usually due to interposed tissue or stretching forces.

Doctor's First Report of Injury - a form completed by a doctor after your first visit; describes the cause of injury, treatment advice, etc. (click here for the form).

Doll’s Eye Sign (Cantelli Sign) – Normally the eyes move with the head.  This sign is present when the eyes move in an opposite direction to the head.  In an unconscious patient, turning the head to the left, for example, will cause the eyes to go to the right.

Doll’s Head Phenomenon – An abnormal muscle sign where the eyes go down as the head is tilted backward.

Dorsal – Refers to the back surface of the body.  This is the opposite of ventral.

Dorsiflexion - To bend the foot upward at the ankle, toward the dorsum (or top) of the foot.

Down Syndrome – A birth defect which is also called mongolism or trisomy-21, this causes multiple problems including developmental delay.

Duchenne Disease – This is an uncommon condition caused by degeneration of portions of the spinal cord.

Duchenne Muscular Dystrophy – Also called infantile muscular atrophy, this birth defect causes severe weakness, delayed walking and other problems.  It occurs only in boys.

Duchenne Sign – Depression of the epigastric region on inspiration which occurs in patients with a paralyzed diaphragm.

Duchenne Syndrome (Duchenne-Erb Syndrome) – This is a damage to the upper roots of the brachial plexus and usually results from an injury.

Duplication Syndrome – Any of a large number of birth defects where there is an extra piece of chromosomal DNA, these are identified by the number of the chromosome and the letter p or q, depending on whether the short or long part of the chromosome is affected.

Dupuytren Operation – This is one type of amputation.

Dupuytren Sign – A crunching sound when moving a damaged joint.

Dura – Layers of tissue covering the brain, the spinal cord, and nerve roots.  Cerebrospinal fluid (CSF) is contained within the dura. The dura can be injured in number of ways (this can cause what is called a CSF leak) and is rarely involved in diseases.

Durable Power of Attorney – A legal document denoting a friend or family member as your legal guardian in case you are unable to make medical decisions for yourself.

Dysequilibrium – Refers to any disturbance of balance or equilibrium.

Disfluency – A disruption in the smooth flow or expression of speech.

DWC-1 - a form completed by a patient to report an injury to an employer (click here for the form).

Dyke-Davidoff-Masson Syndrome – Hemiatrophy of one side of the head and brain causing an asymmetry and unusual facial appearance.

Dynamic Thrust – Chiropractic adjustment delivered suddenly and forcefully to move vertebrae, often resulting in a popping sound.

Dysgeusia – A distortion or absence of the sense of taste.

Dyskinesia – An involuntary movement including athetosis and chorea.

Dysosmia – Distortion or absence of the sense of smell.

If you are aware of any useful spine and neuromusculoskeletal terms which are not included in this list, or if you have suggestions for better definitions,  your help would be greatly appreciated.  Please send me any upgrades and I will update the web site appropriately.  Click here to send a comment.


The information in this site briefly describes issues related to medical treatments, and has been licensed by from Northern California Neurosurgery Medical Group, Inc., who is solely responsible for said content.  This web site is not a substitute for good medical care or for a consultation with a spine specialist. It should not be used to plan your treatment. The well considered advice of a specialist who has personally examined you is always superior to even the best internet pages.

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Last modified: 07/27/08