M
MAGNETIC RESONANCE ANGIOGRAPHY (MRA) - A noninvasive study which is conducted in a Magnetic Resonance Imager (MRI). The magnetic images are assembled by a computer to provide an image of the arteries in the head and neck. No contrast material is needed, but some patients may experience claustrophobia in the imager.
MAGNETIC RESONANCE IMAGING (MRI) - Diagnostic test that produces three-dimensional images of body structures using powerful magnets and computer technology rather than x-rays.
MEDIAL - Situated closer to the midline of the body.
MEDIAN NERVE - The nerve formed from the brachial plexus that supplies muscles in the anterior forearm and thumb, as well as, sensation of the hand. It may be compressed or trapped at the wrist in carpal tunnel syndrome.
MEDICAL DEVICE REPORT (MDR) - The required reporting of medical device complaints involving a patient death, serious injury, or device malfunction.
MEDULLA OBLONGATA - The lower portion of the brain stem.
MEDULLOBLASTOMA - Tumor composed of medulloblasts, which are cells that develop in the roof of the fourth ventricle (medullary velum).
MENINGES - The three membranes covering the spinal cord and brain termed dura mater, arachnoid mater, and pia mater.
MENINGIOMA - A firm, often vascular, tumor arising from the coverings of the brain.
MENINGITIS - An infection or inflammation of the membranes covering the brain and spinal cord.
MENINGOCELE - A protrusion of the coverings of the spinal cord or brain through a defect in the skull or vertebral column.
MENINGOENCEPHALITIS - An inflammation or infection of the brain and meninges.
MENINGOENCEPHALOCELE - A protrusion of both the meninges and brain tissue through a skull defect.
MRA - See magnetic resonance angiography.
MRI - See magnetic resonance imaging.
MESENCEPHALIC - Relating to that part of the brain stem known as the mesencephalon.
MINIMALLY INVASIVE SURGERY - Surgery requiring small incision(s), usually performed with endoscopic visualization.
MYELIN - The fat-like substance which surrounds the axon of nerve fibers and forms an insulating material.
MYELOCELE - Protrusion of the spinal cord in spina bifida.
MYELOGRAM - An x-ray of the spinal canal following injection of a contrast material into the surrounding cerebrospinal fluid spaces.
MYELOMENINGOCELE - A protrusion of the spinal cord and its coverings through a defect in the vertebral column.
MYELOPATHY - Any functional or pathologic disturbance in the spinal cord.
MYOPATHY - Any disease of muscle.
N
NEOPLASM - Any new or abnormal growth, specifically a new growth of tissue in which the growth is uncontrolled.
NERVE ROOT - The portion of a spinal nerve in close proximity to its origin from the spinal cord.
NEURAL ARCH - The bony arch of the posterior aspect of a vertebra that surrounds the spinal cord. Also referred to as the vertebral arch.
NEURALGIA - A paroxysmal pain extending along the course of one or more nerves.
NEURECTOMY - Excision of part of a nerve.
NEURITIS - Inflammation of a nerve. May also be used to denote non-inflammatory nerve lesions of the peripheral nervous system.
NEUROBLASTOMA - Tumor of sympathetic nervous system origin. Found mostly in infants and children.
NEUROFIBROMA - A tumor of the peripheral nerves due to an abnormal collection of fibrous and insulating cells.
NEUROFIBROMATOSIS - A familial condition characterized by developmental changes in the nervous system, muscles and skin, marked by numerous tumors affecting this organ system.
NEUROHYPOPHYSIS - The posterior lobe of the pituitary gland.
NEUROLYSIS - Removal of scar or reactive tissue from a nerve or nerve root.
NEUROMA - A tumor or new growth largely made up of nerve fibers and connective tissue.
NEUROPATHY - Any functional or pathologic disturbance in the peripheral nervous system.
NEUROSTIMULATOR - A device for electrical excitation of the central or peripheral nervous system.
NEUROSURGERY - The surgical specialty involved in the treatment of disorders of the brain, spinal cord, and peripheral nerves.
NONUNION- Failure of the fragments of a fractured bone to heal or to obtain bony fusion following an arthrodesis.
NUCLEUS PULPOSUS - The semi-gelatinous tissue in the center of an intervertebral disc. It is surrounded and contained by the annulus fibrosus which prevents this material from protruding outside the disc space.
NYSTAGMUS - Involuntary rapid movement of the eyes in the horizontal, vertical, or rotary planes of the eyeball.
O
OCCIPUT - The back part of the head.
OLIGODENDROGLIA - Non-nerve cells forming part of the supporting structure of the central nervous system. See glia.
OLIGODENDROGLIOMA - A growth of new cells derived from the oligodendroglia.
OPHTHALMOPLEGIA - Paralysis of one or more of the eye muscles.
ORTHOPAEDIC IMPLANTS - Medical devices used to replace or provide fixation of bone or to replace articulating surfaces of a joint.
ORTHOPAEDICS - The medical specialty involved in the preservation and restoration of function of the musculoskeletal system that includes treatment of spinal disorders and peripheral nerve lesions. Also known as orthopedics.
OSSIFICATION - The process of forming bone in the body.
OSTEOMA - A benign tumor of bone.
OSTEOMYELITIS - Inflammation of bone due to infection, which may be localized or generalized.
OSTEOPOROSIS - A disorder in which bone is abnormally brittle, less dense, and is the result of a number of different diseases and abnormalities.