Back Pain Definitions

Asthma: A common disorder in which chronic inflammation of the bronchial tubes (bronchi) makes them swell, narrowing the airways. Asthma involves only the bronchial tubes and does not affect the air sacs (alveoli) or the lung tissue (the parenchyma of the lung) itself.

Back pain: Pain felt in the low or upper back. There are many causes of back pain.

Bladder: Any pouch or other flexible enclosure that can hold liquids or gases but usually refers to the hollow organ in the lower abdomen that stores urine -- the urinary bladder. The kidneys filter waste from the blood and produce urine, which enters the bladder through two tubes called ureters. Urine leaves the bladder through another tube, the urethra. In women, the urethra is a short tube that opens just in front of the vagina. In men, it is longer, passing through the prostate gland and then the penis. Infection of the bladder is called cystitis.

Blood clots: Blood that has been converted from a liquid to a solid state. Also called a thrombus.

Blood count: The calculated number of white or red blood cells (WBCs or RBCs) in a cubic millimeter of blood.

Bowel: Another name for the intestine. The small bowel and the large bowel are the small intestine and large intestine, respectively.

C-reactive protein: A plasma protein that rises in the blood with the inflammation from certain conditions.

Cancer: An abnormal growth of cells which tend to proliferate in an uncontrolled way and, in some cases, to metastasize (spread).

Cauda equina: A bundle of spinal nerve roots that arise from the bottom end of the spinal cord. The cauda equina comprises the roots of all the spinal nerve roots below the level of the first lumbar (L1) vertebra, namely the sacral and coccygeal nerves. So named because it resembles the tail (Latin, cauda) of a horse (Latin, equus).

Cauda equina syndrome: Impairment of the nerves in the cauda equina, the bundle of spinal nerve roots that arise from the lower end of the spinal cord. The syndrome is characterized by dull pain in the lower back and upper buttocks and lack of feeling (analgesia) in the buttocks, genitalia and thigh, together with disturbances of bowel and bladder function.

CBC: A commonly used abbreviation in medicine that stands for complete blood count, a set values of the cellular (formed elements) of blood. These measurements are generally determined by specially designed machines that analyze the different components of blood in less than a minute.

Chest: The area of the body located between the neck and the abdomen. The chest contains the lungs, the heart and part of the aorta. The walls of the chest are supported by the dorsal vertebrae, the ribs, and the sternum.

Chiropractic: A system of diagnosis and treatment based on the concept that the nervous system coordinates all of the body's functions, and that disease results from a lack of normal nerve function. Chiropractic employs manipulation and adjustment of body structures, such as the spinal column, so that pressure on nerves coming from the spinal cord due to displacement (subluxation) of a vertebral body may be relieved. Practitioners believe that misalignment and nerve pressure can cause problems not only in the local area, but also at some distance from it. Chiropractic treatment appears to be effective for muscle spasms of the back and neck, tension headaches, and some sorts of leg pain. It may or may not be useful for other ailments.

Chronic: This important term in medicine comes from the Greek chronos, time and means lasting a long time.

Chronic pain: Pain (an unpleasant sense of discomfort) that persists or progresses over a long period of time. In contrast to acute pain that arises suddenly in response to a specific injury and is usually treatable, chronic pain persists over time and is often resistant to medical treatments.

Common cold: A viral upper respiratory tract infection. This contagious illness can be caused by many different types of viruses, and the body can never build up resistance to all of them. For this reason, colds are a frequent and recurring problem. In fact kindergarten children average 12 colds per year, while adolescents and adults have around seven colds per year.

Complete blood count: A set values of the cellular (formed elements) of blood. These measurements are generally determined by specially designed machines that analyze the different components of blood in less than a minute.

Compression: 1. The act of pressing together. As in a compression fracture, nerve compression, or spinal cord compression.
2. To shorten in time. In embryology, there may be compression of development with some stages even omitted.

Constipation: Infrequent (and frequently incomplete) bowel movements. The opposite of diarrhea, constipation is commonly caused by irritable bowel syndrome, diverticulosis, and medications (constipation can paradoxically be caused by overuse of laxatives). Colon cancer can narrow the colon and thereby cause constipation. The large bowel (colon) can be visualized by barium enema x-rays, sigmoidoscopy, and colonoscopy. Barring a condition such as cancer, high-fiber diets can frequently relieve the constipation.

COPD: Chronic obstructive pulmonary disease. Any disorder that persistently obstructs bronchial airflow. COPD mainly involves two related diseases -- chronic bronchitis and emphysema. Both cause chronic obstruction of air flowing through the airways and in and out of the lungs. The obstruction is generally permanent and progresses (becomes worse) over time.

Cox-2: Cyclooxygenase-2, a protein acts as an enzyme and specifically catalyzes (speeds) the production of certain chemical messengers called prostaglandins. Some of these messengers are responsible for promoting inflammation. When Cox-2 activity is blocked, inflammation is reduced. Unlike cox-1, cox-2 is active only at the site of inflammation, not in the stomach.

CT scan: Computerized tomography scan. Pictures of structures within the body created by a computer that takes the data from multiple X-ray images and turns them into pictures on a screen. CT stands for computerized tomography.

Depression: An illness that involves the body, mood, and thoughts, that affects the way a person eats and sleeps, the way one feels about oneself, and the way one thinks about things. A depressive disorder is not the same as a passing blue mood. It is not a sign of personal weakness or a condition that can be wished away. People with a depressive disease cannot merely "pull themselves together" and get better. Without treatment, symptoms can last for weeks, months, or years. Appropriate treatment, however, can help most people with depression.

Diagnosis: 1 The nature of a disease; the identification of an illness. 2 A conclusion or decision reached by diagnosis. The diagnosis is rabies. 3 The identification of any problem. The diagnosis was a plugged IV.

Disc: Shortened terminology for an intervertebral disc, a disk-shaped piece of specialized tissue that separates the bones of the spinal column.

Discharge: 1.The flow of fluid from part of the body, such as from the nose or vagina.
2. The passing of an action potential, such as through a nerve or muscle fiber.
3. The release of a patient from a course of care. The doctor may then dictate a discharge summary.

Dysfunction: Difficult function or abnormal function.

Electromyogram: A test used to record the electrical activity of muscles. When muscles are active, they produce an electrical current that is usually proportional to the level of muscle activity. An electromyogram (EMG) is also called a myogram.

Emergency department: The department of a hospital responsible for the provision of medical and surgical care to patients arriving at the hospital in need of immediate care. Emergency department personnel may also respond to certain situations within the hospital such cardiac arrests.

Epidural: Outside the dura, the outermost, toughest, and most fibrous of the three membranes (meninges) covering the brain and the spinal cord. An epidural hematoma is a collection of blood beneath the skull but outside the dura.

Essential: 1. Something that cannot be done without.
2. Required in the diet, because the body cannot make it. As in an essential amino acid or an essential fatty acid.
3. Idiopathic. As in essential hypertension. "Essential" is a hallowed term meaning "We don't know the cause."

Fatigue: A condition characterized by a lessened capacity for work and reduced efficiency of accomplishment, usually accompanied by a feeling of weariness and tiredness. Fatigue can be acute and come on suddenly or chronic and persist.

Fibromyalgia: A syndrome characterized by chronic pain, stiffness, and tenderness of muscles, tendons, and joints without detectable inflammation. Fibromyalgia does not cause body damage or deformity. However, undue fatigue plagues the large majority of patients with fibromyalgia and sleep disorders are common in fibromyalgia.

Fracture: A break in bone or cartilage. Although usually the result of trauma, a fracture can be caused by an acquired disease of bone such as osteoporosis or by abnormal formation of bone in a disease such as osteogenesis imperfecta ("brittle bone disease"). Fractures are classified according to their character and location as, for example, a greenstick fracture of the radius.

Gastric: Having to do with the stomach.

Gastrointestinal: Adjective referring collectively to the stomach and small and large intestines.

Gastrointestinal tract: The tube that extends from the mouth to the anus in which the movement of muscles and release of hormones and enzymes digest food. The gastrointestinal tract starts with the mouth and proceeds to the esophagus, stomach, duodenum, small intestine, large intestine (colon), rectum and, finally, the anus. Also called the alimentary canal, digestive tract and, perhaps most often in conversation, the GI tract.

Headache: A pain in the head with the pain being above the eyes or the ears, behind the head (occipital), or in the back of the upper neck. Headache, like chest pain or back ache, has many causes.

Heart: The muscle that pumps blood received from veins into arteries throughout the body. It is positioned in the chest behind the sternum (breastbone; in front of the trachea, esophagus, and aorta; and above the diaphragm muscle that separates the chest and abdominal cavities. The normal heart is about the size of a closed fist, and weighs about 10.5 ounces. It is cone-shaped, with the point of the cone pointing down to the left. Two-thirds of the heart lies in the left side of the chest with the balance in the right chest.

Heart attack: The death of heart muscle due to the loss of blood supply. The loss of blood supply is usually caused by a complete blockage of a coronary artery, one of the arteries that supplies blood to the heart muscle. Death of the heart muscle, in turn, causes chest pain and electrical instability of the heart muscle tissue.

Herniated disc: Rupturing of the tissue that separates the vertebral bones of the spinal column.

Herniation: Abnormal protrusion of tissue through an opening. For example, a intervertebral disk (one situated between the vertebral bodies) can protrude and impinge on a nerve root.

Herpes: A family of viruses. Herpes also refers to infection with one of the human herpesviruses, especially herpes simplex types 1 and 2.

Herpes zoster: Also called shingles, zona, and zoster. The culprit is the varicella-zoster virus. Primary infection with this virus causes chickenpox (varicella). At this time the virus infects nerves (namely, the dorsal root ganglia) where it remains latent (lies low) for years. It can then be reactivated to cause shingles with blisters over the distribution of the affected nerve accompanied by often intense pain and itching.

Hip fracture: Broken bone in the hip, a key health problem among the elderly, usually due to a fall or other kind of trauma involving direct impact to the hip bone which has been weakened by osteoporosis. The part of the hip most often broken is the greater trochanter (the knobby end) of the femur (the thigh bone).

Ibuprofen: A non-steroidal anti-inflammatory drug (NSAID) commonly used to treat pain, swelling, and fever. Common brand names for Ibuprofen include Advil, Motrin, and Nuprin.

Incidence: The frequency with which something, such as a disease, appears in a particular population or area. In disease epidemiology, the incidence is the number of newly diagnosed cases during a specific time period. The incidence is distinct from the prevalence which refers to the number of cases alive on a certain date.

Incontinence: Inability to control excretions. Urinary incontinence is inability to keep urine in the bladder. Fecal incontinence is inability to retain feces in the rectum.

Indicate: In medicine, to make a treatment or procedure advisable because of a particular condition or circumstance. For example, certain medications are indicated for the treatment of hypertension during pregnancy while others are contraindicated.

Indication: 1. In medicine, a condition which makes a particular treatment or procedure advisable. CML (chronic myeloid leukemia) is an indication for the use of Gleevec (imatinib mesylate). 2. A sign or a circumstance which points to or shows the cause, pathology, treatment, or outcome of an attack of disease. The presence of the Philadelphia chromosome in peripheral blood cells is an indication of a relapse in CML.

Infection: The growth of a parasitic organism within the body. (A parasitic organism is one that lives on or in another organism and draws its nourishment therefrom.) A person with an infection has another organism (a "germ") growing within him, drawing its nourishment from the person.

Inflammation: A basic way in which the body reacts to infection, irritation or other injury, the key feature being redness, warmth, swelling and pain. Inflammation is now recognized as a type of nonspecific immune response.

Injury: Harm or hurt. The term "injury" may be applied in medicine to damage inflicted upon oneself as in a hamstring injury or by an external agent on as in a cold injury. The injury may be accidental or deliberate, as with a needlestick injury. The term "injury" may be synonymous (depending on the context) with a wound or with trauma.

Joint: A joint is the area where two bones are attached for the purpose of motion of body parts. A joint is usually formed of fibrous connective tissue and cartilage. An articulation or an arthrosis is the same as a joint.

Kidney: One of a pair of organs located in the right and left side of the abdomen which clear "poisons" from the blood, regulate acid concentration and maintain water balance in the body by excreting urine. The kidneys are part of the urinary tract. The urine then passes through connecting tubes called "ureters" into the bladder. The bladder stores the urine until it is released during urination.

Knee: The knee is a joint which has three parts. The thigh bone (the femur) meets the large shin bone (the tibia) to form the main knee joint. This joint has an inner (medial) and an outer (lateral) compartment. The kneecap (the patella) joins the femur to form a third joint, called the patellofemoral joint. The patella protects the front of the knee joint.

Leg: In popular usage, the leg extends from the top of the thigh down to the foot. However, in medical terminology, the leg refers to the portion of the lower extremity from the knee to the ankle.

Low back pain: Pain in the lower back area that can relate to problems with the lumbar spine, the discs between the vertebrae, the ligaments around the spine and discs, the spinal cord and nerves, muscles of the low back, internal organs of the pelvis and abdomen, or the skin covering the lumbar area.

Lumbar: Referring to the 5 lumbar vertebrae which are situated below the thoracic vertebrae and above the sacral vertebrae in the spinal column. The 5 lumbar vertebrae are represented by the symbols L1 through L5. There are correspondingly 5 lumbar nerves.

Magnetic resonance imaging: A special radiology technique designed to image internal structures of the body using magnetism, radio waves, and a computer to produce the images of body structures. In magnetic resonance imaging (MRI), the scanner is a tube surrounded by a giant circular magnet. The patient is placed on a moveable bed that is inserted into the magnet. The magnet creates a strong magnetic field that aligns the protons of hydrogen atoms, which are then exposed to a beam of radio waves. This spins the various protons of the body, and they produce a faint signal that is detected by the receiver portion of the MRI scanner. A computer processes the receiver information, and an image is produced. The image and resolution is quite detailed and can detect tiny changes of structures within the body, particularly in the soft tissue, brain and spinal cord, abdomen and joints.

Malignant: 1. Tending to be severe and become progressively worse, as in malignant hypertension. 2. In regard to a tumor, having the properties of a malignancy that can invade and destroy nearby tissue and that may spread (metastasize) to other parts of the body.

Medical history: 1. In clinical medicine, the patient's past and present which may contain clues bearing on their health past, present, and future. The medical history, being an account of all medical events and problems a person has experienced, including psychiatric illness, is especially helpful when a differential diagnosis is needed.
2. The history of medicine.

Motor: In medicine, having to do with the movement of a part of the body. Something that produces motion or refers to motion. For example, a motor neuron is a nerve cell that conveys an impulse to a muscle causing it to contract. The term "motor" today is also applied to a nerve that signals a gland to secrete. Motor is as opposed to sensory.

MRI: Abbreviation  for magnetic resonance imaging.

Muscle: Muscle is the tissue of the body which primarily functions as a source of power. There are three types of muscle in the body. Muscle which is responsible for moving extremities and external areas of the body is called "skeletal muscle." Heart muscle is called "cardiac muscle." Muscle that is in the walls of arteries and bowel is called "smooth muscle."

Myelogram: An x-ray of the spinal cord and the bones of the spine. During a myelogram, a contrast material that is injected into the spinal canal is used to visualize the structures of the spinal cord and nerve roots.

Naproxen: A non-steroidal anti-inflammatory drug (NSAID) used for the management of mild to moderate pain, fever, and inflammation. Naproxen blocks the enzyme cyclooxygenase that makes prostaglandins, resulting in lower concentrations of prostaglandins. As a consequence, inflammation, pain and fever are reduced. Brand names for naproxen include Anaprox, Naprelan, Naprosyn, and Aleve.

Nausea: Nausea, is the urge to vomit. It can be brought by many causes including, systemic illnesses, such as influenza, medications, pain, and inner ear disease. When nausea and/or vomiting are persistent, or when they are accompanied by other severe symptoms such as abdominal pain, jaundice, fever, or bleeding, a physician should be consulted.

Nerve: A bundle of fibers that uses chemical and electrical signals to transmit sensory and motor information from one body part to another.

NSAID: Nonsteroidal anti-inflammatory drug. NSAIDs are commonly prescribed for the inflammation of arthritis and other body tissues, such as in tendinitis and bursitis. Examples of NSAIDs include aspirin, indomethacin (Indocin), ibuprofen (Motrin), naproxen (Naprosyn), piroxicam (Feldene), and nabumetone (Relafen).

Onset: In medicine, the first appearance of the signs or symptoms of an illness as, for example, the onset of rheumatoid arthritis. There is always an onset to a disease but never to the return to good health. The default setting is good health.

Opioid: 1. A synthetic narcotic that resembles the naturally occurring opiates. 2. Any substance that binds to or otherwise affects the opiate receptors on the surface of the cell.

Osteomyelitis: Inflammation of the bone due to infection, for example by the bacteria salmonella or staphylococcus. Osteomyelitis is sometimes a complication of surgery or injury, although infection can also reach bone tissue through the bloodstream. Both the bone and the bone marrow may be infected. Symptoms include deep pain and muscle spasms in the area of inflammation, and fever. Treatment is by bed rest, antibiotics (usually injected locally), and sometimes surgery to remove dead bone tissue.

Osteoporosis: Thinning of the bones with reduction in bone mass due to depletion of calcium and bone protein. Osteoporosis predisposes a person to fractures, which are often slow to heal and heal poorly. It is more common in older adults, particularly post-menopausal women; in patients on steroids; and in those who take steroidal drugs. Unchecked osteoporosis can lead to changes in posture, physical abnormality (particularly the form of hunched back known colloquially as "dowager's hump"), and decreased mobility.

Ovarian: Of or pertaining to the ovary.

Pain: An unpleasant sensation that can range from mild, localized discomfort to agony. Pain has both physical and emotional components. The physical part of pain results from nerve stimulation. Pain may be contained to a discrete area, as in an injury, or it can be more diffuse, as in disorders like fibromyalgia. Pain is mediated by specific nerve fibers that carry the pain impulses to the brain where their conscious appreciation may be modified by many factors.

Pelvic: Having to do with the pelvis, the lower part of the abdomen, located between the hip bones.

Pelvis: The lower part of the abdomen located between the hip bones.

Peripheral: Situated away from the center, as opposed to centrally located.

Pharmacy: A location where prescription drugs are sold. A pharmacy is, by law, constantly supervised by a licensed pharmacist.

Physical therapy: A branch of rehabilitative health that uses specially designed exercises and equipment to help patients regain or improve their physical abilities. Physical therapists work with many types of patients, from infants born with musculoskeletal birth defects, to adults suffering from sciatica or the after- effects of injury, to elderly post-stroke patients.

Placebo: A "sugar pill" or any dummy medication or treatment.

Plantar: Having to do with the sole of the foot.

Posterior: The back or behind, as opposed to the anterior.

Prescription: A physician's order for the preparation and administration of a drug or device for a patient. A prescription has several parts. They include the superscription or heading with the symbol "R" or "Rx", which stands for the word recipe (meaning, in Latin, to take); the inscription, which contains the names and quantities of the ingredients; the subscription or directions for compounding the drug; and the signature which is often preceded by the sign "s" standing for signa (Latin for mark), giving the directions to be marked on the container.

Prognosis: 1. The expected course of a disease.
2. The patient's chance of recovery.
The prognosis predicts the outcome of a disease and therefore the future for the patient. His prognosis is grim, for example, while hers is good.

Progressive: Increasing in scope or severity. Advancing. Going forward. In medicine, a disease that is progressive is going from bad to worse.

Protein: A large molecule composed of one or more chains of amino acids in a specific order determined by the base sequence of nucleotides in the DNA coding for the protein.

Radiate: To spread out from a central area. For example, sciatic pain may radiate outward from the lower back.

Range of motion: The range through which a joint can be moved, usually its range of flexion and extension. Due to an injury, the knee may for example lack 10 degrees of full extension.

Rectum: The last 6 to 8 inches of the large intestine. The rectum stores solid waste until it leaves the body through the anus. The word rectum comes from the Latin rectus meaning straight (which the human rectum is not).

Referred pain: Pain felt at a site other than where the cause is situated. An example is the pain from the pancreas, which is felt in the back. Pain in internal organs is often referred to sites distant from them.

Reflex: A reaction that is involuntary. The corneal reflex is the blink that occurs with irritation of the eye. The nasal reflex is a sneeze.

Rule out: A term much used in medicine, meaning to eliminate or exclude something from consideration. The ACB (albumin cobalt binding) test helps rule out a heart attack in the differential diagnosis of severe chest pain.

Rupture: A break or tear in any organ (such as the spleen) or soft tissue (such as the achilles tendon). Rupture of the appendix is more likely among uninsured and minority children when they develop appendicitis.

Sacral: Referring to the sacrum, the 5 vertebral bones situated between the lumbar vertebrae and the coccyx (the lowest segment of the vertebral column). The 5 sacral vertebrae are represented by the symbols S1 through S5. There are correspondingly 5 sacral nerves. The sacral vertebrae are normally fused to form the sacrum.

Scan: As a noun, the data or image obtained from the examination of organs or regions of the body by gathering information with a sensing device.

Sciatic nerve: The largest nerve in the body, the sciatic nerve begins from nerve roots in the lumbar part of the spinal cord (in the low back) and extends through the buttock area to send nerve endings down to the legs.

Sciatica: Pain resulting from irritation of the sciatic nerve, typically felt from the low back to behind the thigh and radiating down below the knee. While sciatica can result from a herniated disc directly pressing on the nerve, any cause of irritation or inflammation of this nerve can reproduce the painful symptoms of sciatica. Diagnosis is by observation of symptoms, physical and nerve testing, and sometimes by X-ray or MRI if a herniated disk is suspected.

Sedimentation rate: A blood test that detects and monitors inflammation in the body. It measures the rate at which red blood cells (RBCs) in a test tube separate from blood serum over time, becoming sediment in the bottom of the test tube. The sedimentation rate increases with more inflammation. Also called the erythrocyte sedimentation rate. Abbreviated as sed rate or ESR.

Sensation: In medicine and physiology, sensation refers to the registration of an incoming (afferent) nerve impulse in that part of the brain called the sensorium, which is capable of such perception. Therefore, the awareness of a stimulus as a result of its perception by sensory receptors. (Sensory is here synonymous with sensation.)

Sensory: Relating to sensation, to the perception of a stimulus and the voyage made by incoming (afferent) nerve impulses from the sense organs to the nerve centers.

Shingles: An acute infection caused by the herpes zoster virus, the same virus as causes chickenpox. Shingles is most common after the age of 50 and the risk rises with advancing age. Shingles occurs because of exposure to chickenpox or reactivation of the herpes zoster virus. The virus remains latent (dormant) in nerve roots for many years following chickenpox.

Skeletal: Pertaining to the skeleton, the bones of the body which collectively provide the framework for the body.

Spasm: A brief, automatic jerking movement. A muscle spasm can be quite painful, with the muscle clenching tightly. A spasm of the coronary artery can cause angina. Spasms in various types of tissue may be caused by stress, medication, over-exercise, or other factors. 

Spinal cord: The major column of nerve tissue that is connected to the brain and lies within the vertebral canal and from which the spinal nerves emerge. Thirty-one pairs of spinal nerves originate in the spinal cord: 8 cervical, 12 thoracic, 5 lumbar, 5 sacral, and 1 coccygeal. The spinal cord and the brain constitute the central nervous system (CNS). The spinal cord consists of nerve fibers that transmit impulses to and from the brain. Like the brain, the spinal cord is covered by three connective-tissue envelopes called the meninges. The space between the outer and middle envelopes is filled with cerebrospinal fluid (CSF), a clear colorless fluid that cushions the spinal cord against jarring shock. Also known simply as the cord.

Spinal stenosis: Narrowing of the spaces in the spine, resulting in compression of the nerve roots or spinal cord by bony spurs or soft tissues, such as disks, in the spinal canal. This occurs most often in the lumbar spine (in the low back) but also occurs in the cervical spine (in the neck) and less often in the thoracic spine (in the upper back).

Spine: 1) The column of bone known as the vertebral column, which surrounds and protects the spinal cord. The spine can be categorized according to level of the body: i.e., cervical spine (neck), thoracic spine (upper and middle back), and lumbar spine (lower back). See also vertebral column. 2) Any short prominence of bone. The spines of the vertebrae protrude at the base of the back of the neck and in the middle of the back. These spines protect the spinal cord from injury from behind.

Spondylitis: Inflammation of one or more of the vertebrae of the spine. Diffuse inflammation of the spine is seen in the disease ankylosing spondylitis. Localized spondylitis is seen with infections of a certain area of the spine, such as in Pott's disease.

Spondylosis: Degeneration of the disc spaces between the vertebrae. This finding in the spine is commonly associated with osteoarthritis.

Stenosis: A narrowing, as in:

• aortic stenosis (narrowing of the aortic valve of the heart),
• pulmonary stenosis (narrowing of the pulmonary valve of the heart),
• pyloric stenosis (narrowing of the outlet of the stomach), and
• spinal stenosis (narrowing of the vertebral canal).

Steroid: A general class of chemical substances that are structurally related to one another and share the same chemical skeleton (a tetracyclic cyclopenta[a]phenanthrene skeleton).

Stomach: The sac-shaped digestive organ that is located in the upper abdomen, under the ribs. The upper part of the stomach connects to the esophagus, and the lower part leads into the small intestine.

Stool: The solid matter discharged in a bowel movement.

Strain: 1. An injury to a tendon or muscle resulting from overuse or trauma. 2. A hereditary tendency that originated from a common ancestor. 3. To exert maximum effort. 4. To filter.

Stress: Forces from the outside world impinging on the individual. Stress is a normal part of life that can help us learn and grow. Conversely, stress can cause us significant problems.

Stroke: The sudden death of some brain cells due to a lack of oxygen when the blood flow to the brain is impaired by blockage or rupture of an artery to the brain. A stroke is also called a cerebrovascular accident or, for short, a CVA.

Surgery: The word "surgery" has multiple meanings. It is the branch of medicine concerned with diseases and conditions which require or are amenable to operative procedures. Surgery is the work done by a surgeon. By analogy, the work of an editor wielding his pen as a scalpel is s form of surgery. A surgery in England (and some other countries) is a physician's or dentist's office.

Symptom: Any subjective evidence of disease. Anxiety, lower back pain, and fatigue are all symptoms. They are sensations only the patient can perceive. In contrast, a sign is objective evidence of disease. A bloody nose is a sign. It is evident to the patient, doctor, nurse and other observers.

Syndrome: A set of signs and symptoms that tend to occur together and which reflect the presence of a particular disease or an increased chance of developing a particular disease.

Tension: 1) The pressure within a vessel, such as blood pressure: the pressure within the blood vessels. For example, elevated blood pressure is referred to as hypertension. 2) Stress, especially stress that is translated into clenched scalp muscles and bottled-up emotions or anxiety. This is the type of tension blamed for tension headaches.

Therapy: The treatment of disease.

Thoracic: Pertaining to the chest.

Topical: Pertaining to a particular surface area. A topical agent is applied to a certain area of the skin and is intended to affect only the area to which it is applied. Whether its effects are indeed limited to that area depends upon whether the agent stays where it is put or is absorbed into the blood stream.

Trauma: Any injury, whether physically or emotionally inflicted. "Trauma" has both a medical and a psychiatric definition. Medically, "trauma" refers to a serious or critical bodily injury, wound, or shock. This definition is often associated with trauma medicine practiced in emergency rooms and represents a popular view of the term. In psychiatry, "trauma" has assumed a different meaning and refers to an experience that is emotionally painful, distressful, or shocking, which often results in lasting mental and physical effects.

Trigger: Something that either sets off a disease in people who are genetically predisposed to developing the disease, or that causes a certain symptom to occur in a person who has a disease. For example, sunlight can trigger rashes in people with lupus.

Tumor: An abnormal mass of tissue. Tumors are a classic sign of inflammation, and can be benign or malignant (cancerous). There are dozens of different types of tumors. Their names usually reflect the kind of tissue they arise in, and may also tell you something about their shape or how they grow. For example, a medulloblastoma is a tumor that arises from embryonic cells (a blastoma) in the inner part of the brain (the medulla). Diagnosis depends on the type and location of the tumor. Tumor marker tests and imaging may be used; some tumors can be seen (for example, tumors on the exterior of the skin) or felt (palpated with the hands).

Urinary: Having to do with the kidneys, ureters, and bladder. The urinary system represents the functional and anatomic aspects of the kidneys, ureters, and bladder.

Virus: A microorganism smaller than a bacteria, which cannot grow or reproduce apart from a living cell. A virus invades living cells and uses their chemical machinery to keep itself alive and to replicate itself. It may reproduce with fidelity or with errors (mutations)-this ability to mutate is responsible for the ability of some viruses to change slightly in each infected person, making treatment more difficult.

Weight loss: Weight loss is a decrease in body weight resulting from either voluntary (diet, exercise) or involuntary (illness) circumstances. Most instances of weight loss arise due to the loss of body fat, but in cases of extreme or severe weight loss, protein and other substances in the body can also be depleted. Examples of involuntary weight loss include the weight loss associated with cancer, malabsorption (such as from chronic diarrheal illnesses ), and chronic inflammation (such as with rheumatoid arthritis).

X-ray: 1. High-energy radiation with waves shorter than those of visible light. X-rays possess the properties of penetrating most substances (to varying extents), of acting on a photographic film or plate (permitting radiography), and of causing a fluorescent screen to give off light (permitting fluoroscopy). In low doses X-rays are used for making images that help to diagnose disease, and in high doses to treat cancer. Formerly called a Roentgen ray. 2. An image obtained by means of X-rays