Medical/Neurosurgical Glossary
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Magnetic Resonance Imaging (MRI) – A non-invasive procedure that produces a two-dimensional view of an internal organ or structure.

Maintenance Care – A subluxation-based program of periodic spinal examinations and "adjustments" alleged to help maintain the patient's health. This is a type of "preventive maintenance.”

Malabsorption Syndrome – Poor absorption of protein and other nutrients in the intestine or gut causes diarrhea, fatigue and other neurologic diseases.

Managed Care Plans -- Managed care plans are those where the insurance company makes treatment decisions for the patients.  They include HMO’s, PPO’s, and Kaiser plans.  The insurance companies limit your care in order to save them money.  These plans are usually much less expensive than indemnity insurance.

Manipulation Under Anesthesia (MUA) – A procedure in which an orthopedist or a chiropractor performs manipulation while an anesthesiologist keeps the patient asleep. This works well for some shoulder conditions but is very dangerous when used in the spine and can cause quadriplegia.  

Marcus Gunn Phenomenon – This is an involuntary closure of the eye when the jaw is moved due to an injury of the facial nerve. 

Marcus Gunn Pupillary Sign – Also known as the swinging light test, this identifies a poor visual response with an intact pupillary response as one sees in certain types of inflammation or multiple sclerosis.

Marfan Syndrome – This is a birth defect where connective tissue is abnormal.  Patients tend to be tall but have many blood vessel problems. 

Marie Ataxia, Marie Syndrome – An incoordination due to abnormalities of the cerebellum and the peduncles of the cerebellum.

Massage – A mechanical form of therapy in which the soft tissues are made more pliable with different techniques, promoting increased blood flow and subsequent healing.

Mastoid Process – The bump or prominence behind and below each ear supports the muscles that keep the head erect.

Maximal Medical Improvement - under Federal and some non-California systems, when improvement stops and impairment can be calculated.

McBurney Point – A spot half way from the navel to the pelvis on the right where one usually has pain from appendicitis.

Meckel Cave – This is the small cavity where the trigeminal nerve (facial sensation nerve) exits the skull.

Median Nerve – This is a large nerve, arising from segments of the cervical spine.  It is commonly entrapped in the carpal tunnel of the wrist.

Medical-Legal – A medical-legal evaluation is completed by a doctor for legal purposes (as opposed to treatment).  For example, a report may be ordered to resolve disputes regarding the nature or severity of an injury.  It may include a physical evaluation of the patient.  It may include a record review.  It may include both.  It does not include treatment.

Medically Necessary – This is a common phrase used in a peculiar way by medical insurance companies and which results in great confusion.  When an insurance company uses the word “necessary” they indicate that they are willing to pay.  If they say “not necessary” they mean that they will not pay.  It has nothing to do with a patient’s need for a treatment.  For example, an insurance denial form may use the abbreviation, “MED PROC NOT NEC” to indicate that they have decided that the procedure is “not necessary” for the patient, and that they do not wish to pay for any charges.

MED PROC NOT NEC – This is an abbreviation commonly used by medical insurance companies.  It means “medical procedure not necessary.”  A patient’s treatment may be needed in the opinion of the doctors and may even be an emergency.  If this abbreviation is used on an insurance form, however, it means that the insurance contract does not require that the insurance company pay for the care.

Medial – Situated closer to the midline of the body.  It is the opposite of lateral.

Ménière Disease, Ménière Syndrome – Vertigo due to damage of the inner ear device, this was first described in 1848.

Meniscus – A part of the cartilage in the knees and other joints.

Menkes Syndrome (Kinky-Hair Syndrome) – This is a birth defect with unusually curled hair among other anomalies.

Mercy Guidelines – The common name for the report issued following the chiropractic consensus conference held at the Mercy Conference Center in Burlingame, California, in January, 1992. The report is a step toward establishing parameters and guidelines for the profession. Many insurance companies use it as a guide to the appropriateness of chiropractic treatment.

Meric System – This is a chiropractic system that is based on the theory that specific spinal joints are associated with specific organs, requiring adjustment of certain vertebrae for certain diseases.

Microdiscectomy – An operation used to remove a portion of a damaged disc and correct a pinched nerve.  It is the current “gold standard” of treatment.  The incision is smaller and the tissue damage is less than with older techniques.  It does not rely on experimental tools and has been used successfully by thousands of doctors on millions of patients for at least 30 years. 

Millard-Gubler Syndrome – A paralysis affecting one side of the face and the opposite side of the body, this is similar the Brown-Sequard syndrome except it occurs in the brain stem instead of the spinal cord.

Miller Fisher Syndrome – A disturbance of gaze, the patient is unable to look in certain directions with this syndrome.

Minimal - under California law describes the severity of a pain as an annoyance; of "minimal," "slight," "moderate," and "severe."

Minimally Invasive Surgery – Surgery requiring one or more small incisions instead of a single large incision.  It is usually performed with endoscopic or microscopic instruments. The goal of minimally invasive surgery is to decrease pain, decrease hospital stays, and save costs.  The risks are often slightly greater than with conventional “open” surgery.

Mixer – a chiropractor who uses physical therapy and other natural treatment methods in addition to manual manipulation of the spine.

Monoclonal Antibodies – Substances that can locate and bind to cancer cells wherever they are in the body.

Mobilization – A method of manipulation, movement, or stretching to increase range of motion in muscles and joints that does not involve a high-velocity thrust.

Moderate - under California law describes the severity of a pain as causing a marked hindrance in performing an activity; of "minimal," "slight," "moderate," and "severe."

Moire Contour-graphic Analysis – This is a chiropractic procedure in which an angled light is passed through a grid to the surface of the patient's body to produce a pattern of shadows that is viewed on a screen and/or photographed. The resultant picture resembles a topographic map. This is also called a contour analysis.

Morlan Reflex – This is similar to a Babinski sign but is caused by scratching the big toe near the ball of the foot.

Morton's Neuroma – This is a painful condition of one of the digital branches of the plantar nerves in the foot.

Motion palpation – Useful chiropractic method of locating fixations and loss of mobility in the spine by feeling the motion of specific spinal segments as the patient moves.

MUA (Manipulation Under Anesthesia) – A procedure in which an orthopedist or a chiropractor performs manipulation while an anesthesiologist keeps the patient asleep. This works well for some shoulder conditions but is very dangerous when used in the spine and can cause quadriplegia.

Münchhausen Syndrome – A collection of symptoms that are either not real or are exaggerated by a person who seeks to get medical care or a disability payment that is not needed.

Musculoskeletal System – The complex system that includes the bones, joints, ligaments, tendons, muscles, and nerves are responsible for all movement.

Myelogram – A specific x-ray study that uses an injection of a dye or contrast material into the spinal canal to allow careful evaluation of the spinal canal and nerve roots.

Myasthenia Gravis Syndrome – The same as Lambert syndrome, a type of muscle damage that causes proximal weakness.  This is rare but very severe..

Myasthenic Syndrome – This type of muscle weakness is due to an immunologic reaction to the chemicals that cause muscles to contract.

Myoclonus – A jerking, involuntary movements of the arms and legs; may occur normally during sleep.

Myofascial Pain – The most common form of temporomandibular disorder; discomfort or pain in the muscles that control jaw function and the neck and shoulder muscles.

Myofascial Trigger Point - areas of focal muscle tenderness and spasm.

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.