ice therapy - cooling of deeper tissues

idiopathic - of unknown origin  

ileocolitis - irritation of the lower part of the small intestine (ileum) and colon

ileostomy - operation that makes it possible for stool to leave the body, after the colon and rectum are removed, in which an opening is made in the abdomen and the bottom of the small intestine (ileum) attaches to it. 

ileum - lower end of the small intestine.

imaging - tests or evaluation procedures that produce pictures of areas inside the body.

immobilization - preventing movement to allow for natural healing to take place.  

immune system - complex network of specialized cells and organs that work together to defend the body against attacks by "foreign" invaders such as bacteria and viruses.

immunoglobulin E (IgE) - a type of antibody, formed to protect the body from infection, which attaches to mast cells in the respiratory and intestinal tracts and may cause allergic rhinitis, asthma, or eczema.    

immunoglobulins - antibodies or proteins found in blood and tissue fluids produced by cells of the immune system to bind to substances in the body that are recognized as foreign antigens. Immunoglobulins sometimes bind to antigens that are not necessarily a threat to healt

immunology - the study of the body's immune system - its functions and disorders.

immunosuppresive medications - medications that suppress the body's immune system; often used to minimize rejection of transplanted organs.   

immunotherapy (Also called biological therapy.) - treatment that uses the body's natural defenses to fight disease.

impaction - trapping of an object in a body passage, such as stones in the bile duct or hardened stool in the colon.

impaired glucose tolerance (IGT) - a condition in which blood sugar levels are higher than normal, but are not high enough to be classified as diabetes; a risk factor for type 2 diabetes.

impedance plethysmography - a test to evaluate blood flow through the leg.

in vitro fertilization - treatment for infertility in which a woman's egg is fertilized, outside her body, with her partner's sperm or sperm from a donor.

infection - the invasion of the body by microorganisms that cause disease.

inferior vena cava - the large blood vessel (vein) that returns blood from the legs and abdomen to the heart.

inflammation - characteristic reaction of tissues to injury or disease marked by four signs: swelling, redness, heat, and pain.  

inflammatory bowel disease (IBD) - long-lasting problems that cause irritation and ulcers in the gastrointestinal (GI) tract - the most common disorders are ulcerative colitis and Crohn's disease.

informed consent form - a form signed by the patient prior to surgery which explains everything involved in the surgery, including its risks.

inner ear - part of the ear that contains both the organ of hearing (the cochlea) and the organ of balance (the labyrinth). 

inotropic medications - medications that increase strength of the contractions in the heart.

inpatient surgery - surgery which requires the patient to be admitted and stay in the hospital.

inspiration - inhaling; taking in oxyge

insulin - a hormone produced by the pancreas. Insulin affects the amount of glucose absorbed by the liver.   

intercostal muscles - muscles lying between ribs; often injured by rotary stress of the thorax.

interferon - a biological response modifier that stimulates the growth of certain disease-fighting blood cells in the immune system; used to treat cancer and other diseases.

interleukin-2 - a biological response modifier that stimulates the growth of certain blood cells in the immune system that can fight cancer and other diseases.

intervertebral disc - disc that forms a cartilaginous joint between the vertebral bodies, to provide shock absorption.

intestinal mucosa - surface lining of the intestines where the cells absorb nutrients.  

intestines - see large intestine and small intestine.  

intolerance - allergy or sensitivity to a food, drug, or other substance.

intra-articular - within the joint 

intrauterine insemination - treatment for infertility in which semen is introduced into the uterus via a slim tube inserted through the vagina.

intravenous line - a thin plastic tube inserted into a vein (usually in the patient s forearm) through which a volume of fluid is injected into the bloodstream.

intrinsic asthma - asthma that has no apparent external cause.    

invasive cancer - cancer that begins an one area and then spreads deeper into the tissues of that area.

ischemia - decreased flow of oxygenated blood to an organ due to obstruction in an artery.

ischemic heart disease - coronary artery disease or coronary heart disease caused by narrowing of the coronary arteries and decreased blood flow to the heart.

isometric - muscle contraction without movement at the joint.  

isthmus - tissue that connects the two lobes of the thyroid.