Glossary: M

macrodactyly

a congenital problem in which there is an abnormal growth of a finger.

macrosomia

term meaning "large body;" refers to a baby that is considered larger than normal; a condition that occurs when the mother's blood sugar levels have been higher than normal during the pregnancy; a preventable complication of gestational diabetes.

macula

the portion of the eye that allows us to see fine details clearly.

macular degeneration

degeneration in the macular region of the retina that results in decreased central vision and sometimes, in blindness.

macular stains (also called angel's kisses or stork bites)

faint, red marks that appear in the skin at birth. Angel's kisses are marks on the forehead and eyelids. Stork bites are marks on the back of the neck.

macule

the smaller version of a patch

mad cow disease

scientifically known as bovine spongiform encephalopathy (BSE), this disease in cattle is related to a disease in humans called new variant Creutzfeldt-Jakob disease (nvCJD).

magnetic resonance imaging (MRI)

a diagnostic procedure that uses a combination of large magnets, radiofrequencies, and a computer to produce detailed images of organs and structures within the body.

major depression (also known as clinical depression.)

classified as a type of affective disorder or mood disorder that goes beyond the day's ordinary ups and downs, becoming a serious medical condition and important health concern in this country.

malabsorption syndromes

conditions that happen when the small intestine cannot absorb nutrients from foods.

malaria

a disease caused by a parasite that is transmitted person-to-person by the bite of an infected Anopheles mosquito. These mosquitoes are present in the tropics and subtropics in almost all countries. Malaria is the most deadly of all tropical parasitic diseases.

malignant

cancerous cells that can invade other parts of the body.

malignant melanoma

a rare, but sometimes deadly, skin cancer that begins as a mole that turns cancerous.

malignant tumor

a mass of cancer cells that may invade surrounding tissues or spread to distant areas of the body.

malnutrition

condition caused by not eating enough food or not eating a balanced diet.

malocclusion

an orthodontic problem that means "bad bite," including crowded, missing, or crooked teeth, extra teeth, or a misaligned jaw.

mammogram

an x-ray of the breast used to detect and diagnose breast disease.

mania

a mood disorder which may be characterized by extreme elation, impulsivity, irritability, rapid speech, nervousness, distractibility, and/or poor judgment.

manic depression (also known as bipolar disorder)

classified as a type of affective disorder or mood disorder that goes beyond the day's ordinary ups and downs. Manic depression is characterized by periodic episodes of extreme elation, elevated mood, or irritability (also called mania) countered by periodic, classic depressive symptoms.

manometry

tests that measure muscle pressure and movements in the GI tract.

Mantoux test

A skin test used to identify most people with M. tuberculosis within six to eight weeks after initial exposure.

manual therapy

passive movement techniques.

massage

mechanical form of therapy in which the soft tissues are made more pliable, promoting increased blood flow and healing.

mast cells

cells, which synthesize and store histamines, found in most body tissues, particularly just below the epithelial surfaces, serous cavities and around blood vessels. In an allergic response, an allergen stimulates the release of antibodies, which attach themselves to mast cells.

mastalgia

pain in the breast that is generally classified as either cyclical (associated with menstrual periods) or noncyclical.

mastectomy

surgery to remove portions or all of the breast.

mastitis

an inflammation of the breast tissue.

mastoid

back portion of the temporal bone behind the ear.

mastoid surgery

surgical procedure to remove infection from the mastoid bone.

maxillofacial

pertaining to the jaws and face.

meal plan

a guide to help people get the proper amount of calories, carbohydrates, proteins, fats, vitamins, minerals, and fiber in their diet.

mean blood pressure

average blood pressure, taking account of the rise and fall that occurs with each heartbeat. It is often estimated by multiplying the diastolic pressure by two, adding the systolic pressure, and then dividing this sum by three.

measles

a very contagious viral illness characterized by a distinct rash and a fever; spread through airborne droplets of nasal secretions.

Meckel's diverticulum

birth defect in which a small sac forms in the ileum.

meconium

a sticky, greenish-black substance that forms in the intestines during fetal development and is the first bowel movement of a newborn.

medial collateral ligament (MCL)

the ligament that gives stability to the inner knee.

median nerve

large nerve, comprising segments from the cervical spine, that is involved in nerve function of the upper limb; commonly compressed in the carpal tunnel of the wrist.

Medicaid

federally and state-funded health care program for low-income individuals.

Medicare

federally funded health care program for individuals over age 65.

megacolon

huge, swollen colon; results from severe constipation.

megaloblastic (pernicious) anemia

a rare blood disorder in which the body does not absorb enough vitamin B12 from the digestive tract, resulting in an inadequate amount of red blood cells produced.

Meige syndrome

a movement disorder that can involve excessive eye blinking (blepharospasm) with involuntary movements of the jaw muscles, lips, and tongue (oromandibular dystonia).

melanin

a substance that gives the skin its color (also called pigment).

melanoma

the most serious, life-threatening form of skin cancer.

memelasma

dark, brown symmetrical patches of pigment on the face.

melena

blood in the stool.

menarche

a young woman's first menstrual period.

meninges

the thin layers of tissue that cover the brain. The three layers are the dura mater, the arachnoid, and the pia mater.

meningitis

inflammation of the meninges, the membranes that envelop the brain and the spinal cord; may cause hearing loss or deafness.

menisci

two crescent-shaped discs of connective tissue between the bones of the knees that act as shock absorbers to cushion the lower part of the leg from the weight of the rest of the body.

menorrhagia

the most common type of abnormal uterine bleeding (also called dysfunctional uterine bleeding) characterized by heavy and prolonged menstrual bleeding. In some cases, bleeding may be so severe and relentless that daily activities become interrupted.

menses

menstrual flow.

menstruation

a monthly process (except during pregnancy) that involves a discharge of bloody fluid from the uterus through the vagina; the discharge contains tissue shed from the endometrium (the lining of a woman's uterus) during the reproductive cycle.

mercury poisoning

an abnormal condition caused by breathing or swallowing a mercury substance.

metabolism

the chemical activity that occurs in cells, releasing energy from nutrients or using energy to create other substances, such as proteins.

metaplasia

the phenomenon by which one type of tissue is replaced by another type.

metastasis

the spread of cancer cells to distant areas of the body by way of the lymph system or blood stream.

metastasize

when cancer cells spread to other parts of the body.

methyl-tert-butyl ether

a solution injected into the gallbladder to dissolve gallstones.

metrorrhagia

any irregular, acyclic non-menstrual bleeding from the uterus; bleeding between menstrual periods.

micrographia

a change in handwriting with the script becoming smaller and more cramped.

microsurgical fertilization

a procedure used to facilitate sperm penetration into the oocyte, and fertilization takes place under the microscope.

middle ear

part of the ear that includes the eardrum and three tiny bones of the middle ear, ending at the round window that leads to the inner ear.

milia

tiny, white, hard spots that look like pimples on a newborn's nose.

minimally invasive surgery

any technique involved in surgery that does not require a large incision. (See also endoscopy, abdominoscopy, or laparoscopy.)

miosis

constriction of the pupil.

misarticulation

inaccurately produced speech sound (phoneme) or sounds.

miscarriage

spontaneous termination of a pregnancy before the fetus has developed enough to survive outside the uterus.

mitral valve

the valve that controls blood flow between the left atrium and left ventricle in the heart.

mitral valve prolapse

a bulge in the valve between the left atrium and left ventricle of the heart that causes backward flow of blood into the atrium.

mobility

movement.

modified radical mastectomy

the removal of the entire breast (including the nipple, the areola, and the overlying skin), some of the lymph nodes under the arm (also called the axillary lymph glands), and the lining over the chest muscles. In some cases, part of the chest wall muscles is also removed.

mold

a microscopic fungus that grows and lives on plant or animal matter or on non-organic objects. Most molds are made up of filaments and reproduce through the production of spores, which spread by air, water, or insects.

moles

small skin marks caused by pigment-producing cells in the skin.

Mongolian spots

bluish-black marks on the lower back and buttocks; affects mainly African-American or Asian children.

monoamine oxidase (MAO)

an enzyme that breaks down dopamine. There are two types of MAO "A" and "B." In Parkinson's disease, it is beneficial to block the activity of MAO B.

monoclonal antibodies

substances that can locate and bind to cancer cells wherever they are in the body.

monounsaturated fats

dietary fats, such as olive oil or canola oil, that do not seem to have any affect on blood cholesterol.

mood disorder (also known as affective disorder)

a category of mental health problems which includes depressive disorders.

morning-after pills

hormonal medications to prevent pregnancy taken within 72 hours of having unprotected intercourse.

Moro reflex

Movement of arms and legs that occurs when a newborn is startled by a loud sound or movement.

Morton's neuroma

A pinched nerve that usually causes pain between the third and fourth toes.

motility

motility.

motion sickness

dizziness, sweating, nausea, vomiting, and generalized discomfort experienced when an individual is in motion.

motor speech disorders

group of disorders caused by the inability to accurately produce speech sounds (phonemes).

moulding

elongation of the shape of a baby's head due to delivery through the birth canal.

moxibustion

the burning of herbal leaves on or near the body.

mucosal lining

lining of GI tract organs that makes mucus.

mucosal protective drugs

medications that protect the stomach lining from acid.

mucus

a thick, jelly-like substance made by the intestines and other organs of the body (such as the nose), that helps coat and protect the lining of the organ. Mucus also helps stool pass through the large intestine and rectum more easily.

multifidus

deep lumbar spine muscle that stabilizes the lumbar spine.

multiple chemical sensitivity

a diagnostic label for people who suffer multi-system illnesses as a result of contact with, or proximity to, a variety of airborne agents and other substances.

multiple sclerosis (MS)

a disease of the central nervous system that is an unpredictable condition that can be relatively benign, disabling, or devastating, leaving the patient unable to speak, walk, or write.

multiple semen analysis

at least two semen examples are collected on separate days to examine the semen and sperm for various factors, such as semen volume, consistency, and pH, and the sperm count, motility, and morphology (shape).

mumps

an acute and highly contagious viral disease that usually occurs in childhood. Spread by airborne droplets from the upper respiratory tract, the disease usually takes two to three weeks to appear.

murmur

a blowing or rasping sound heard while listening to the heart that may or may not indicate problems within the heart or circulatory system.

muscular dystrophy (MD)

a broad term that describes a genetic (inherited) disorder of the muscles. MD causes the muscles in the body to become very weak. The muscles break down and are replaced with fatty deposits over time. The most common form of MD is called Duchenne muscular dystrophy (DMD).

musculoskeletal system

the complex system involving the body's muscles and skeleton, and including the joints, ligaments, tendons, and nerves.

mycoplasma

very common sexually transmitted disease or urinary tract infection caused by a bacteria-like organism in the urethra and reproductive system.

mycosis fungoides

cutaneous T-cell lymphoma skin tumors.

mydriasis

dilation of the pupil.

myelogenous leukemia

a type of leukemia in which the cancer develops in the granulocytes or monocytes (myeloid cells).

myelogram

involves the injection of a dye or contrast material into the spinal canal; a specific x-ray study that also allows careful evaluation of the spinal canal and nerve roots.

myeloproliferative disorders

diseases in which the bone marrow produces too many of one of the three types of blood cells: red blood cells, which carry oxygen to all the tissues in the body; white blood cells, which fight infection; and platelets, which makes blood clot.

myocardial infarction (also called heart attack)

occurs when one of more regions of the heart muscle experience a severe or prolonged decrease in oxygen supply caused by a blocked blood flow to the heart muscle.

myocardial ischemia

insufficient blood flow to part of the heart.

myocardium

the muscle wall of the heart.

myoclonus

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

myofascial pain

an aching pain in muscles that tends to be associated with poor posture; patients can become sore in different parts of the body, such as the neck and arms, and often report they have difficulty sleeping or feeling restored from sleep.

myofascial trigger point

areas of focal muscle tenderness and spasm.

myomectomy

surgical procedure done to remove fibroids from the uterus and leaving the uterus intact.

myopia

nearsightedness.

myringotomy

a surgical opening of the eardrum to release pressure on the middle ear.

Ménétrier's disease (also called giant hypertrophic gastritis)

Long-term disorder that causes large, coiled folds in the stomach.

Ménière's disease

An inner ear disorder that can affect both hearing and balance; can cause vertigo, hearing loss, tinnitus, and the sensation of fullness in the ear.

Ménière's disease

An inner ear disorder that can affect both hearing and balance; can cause vertigo, hearing loss, tinnitus, and the sensation of fullness in the ear.

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