Glossary – M
magnetic resonance imaging: A way of visualizing the interior of the body using magnetic and radiofrequency fields.
marrow: Tissue within bone that helps form new blood cells.
medial: Towards the midline or the opposite of lateral.
median nerve: A nerve that starts in the shoulder area and then runs into the hand. It carries sensory fibers to the thumb and first two fingers and motor nerves to the upper arm and to the base of the thumb to enable flexion of the fingers.
Medicare: Health care financing provided for individuals over 65 and for those who are disabled, under supervision of the Federal Government – also Health Care Financing Administration (HCFA) and Centers for Medicare and Medicaid Services (CMS).
meninges: The various membranes that line the spinal cord and brain.
meningioma: A tumor that derives from the membranes around the spinal cord or brain.
meningitis: An infection in the spinal fluid and in the membranes around the spinal cord and brain.
metastatic: A tumor that spreads to various locations within the body.
microdiscectomy: The removal of lumbar disc material under microscope magnification.
microplates: Small titanium plates, used to hold the bones in position after repair, closure or fusion.
modalities: Different types of physical therapy treatment such as ultrasound, stretching and strengthening.
modulus of elasticity: The degree to which a structure can be bent and returned to its previous shape.
motor evoked potentials: Activation of the movement system, which is induced with magnetic fields applied over the surface of the brain.
motor neurons: Nerve cells in the spinal cord that operate muscles.
motor units: Groups of muscle cells operated by the branches of a single motor nerve cell.
MR Angiography: An image of the blood vessels, obtained using MRI scanning without any requirement for injection of contrast into the blood system.
MR Neurography: A method for imaging nerves with specialized MRI scanning.
multidisciplinary pain management: An approach to pain management that involves psychology, psychiatry, anesthesia, and nursing as a multi-specialty team.
muscle spasm: Abnormal, prolonged tension in a muscle group, typically causing pain.
musculocutaneous nerve: A nerve originating in the shoulder that activates the biceps muscle.
musculoskeletal: Anything pertaining to the bones, muscles, tendons and ligaments.
myelin: A fatty material that surrounds and insulates the nerve cells and allows them to conduct their electrical signals optimally.
myelogram: An X-ray and CT image of the spinal cord and nerve roots, produced by injecting contrast dye into the spinal fluid. Magnetic Resonance (MR) Myelograms do not require any injections
myelomeningocele: A birth defect affecting the spine, in which the spinal cord may be exposed through the skin.
myelopathy: Symptoms that arise when the spinal cord is compressed.