ICD-9-CM - ICD-9-CM - International Classification of Diseases, Ninth Revision, Clinical Modification. ICD-9-CM is a clinically modified statistical classification system that arranges diseases and injuries into groups according to established criteria. It is based on the ICD-9, which was designed for the classification of morbidity and mortality information for statistical purposes, and published by the World Health Organization (WHO).

ICD-O - ICD-O - International Classification of Diseases for Oncology. Most registries are currently using the Third Edition of the ICD-O (ICD-O-3).

Idiopathic - Refers to a disease or condition of unknown cause or origin.

ileum - Greek eilein = twisted. adjective - ileal.

Iliacus - (L. ilium, groin). A muscle of the groin.

Ilio- - (L. ilium, groin). Pertaining to a muscle of the groin and ilium.

ilium - Latin the bone of the flank, adjective - iliac.

ima - adjective, Latin = lowest, hence artery thyroidea ima.

Immune System - A complex system of cellular and molecular components having the primary function of distinguishing self from not self and defense against foreign organisms or substances. The primary cellular components are lymphocytes and macrophages, and the primary molecular components are antibodies and lymphokines; granulocytes and complement system are also involved in immune responses, although they are not always considered as part of the immune system per se.

Immunoglobulin - An antibody or, more generally, antibodies which provide protection against infectious agents. Immunoglobulins are produced by lymphocytes of the B cell type in response to the stimulation of infectious agents or the contents of vaccines. Immunoglobulins are soluble proteins present in blood serum and other body fluids. Temporary protection via immunoglobulins can be transferred to another person through injection of a purified portion of a donor's serum.

Immunosuppression - The artificial suppression of the immune response, usually through drugs, so that the body will not reject a transplanted organ or tissue. Drugs commonly used to suppress the immune system after transplant include prednisone, azathioprine (Imuran), cyclosporin, OKT3 and ALG.

Immunotherapy - Treatment of disease by stimulating the body's own immune system. This is a type of therapy currently being researched as a treatment for cancer.

impar - Latin = unpaired.

Incidence - The rate at which a certain event occurs (e.g., the number of new cases of specific disease occurring during a certain period of time).

Incisional Biopsy - An incisional biopsy is different from an excisional biopsy because the surgeon does not attempt to remove the entire mass. An incisional biopsy is performed to abtain a fragment of tissue to send to the pathologist for diagnosis.

incisor - Latin incisum = cut up.

incisura - Latin = notch.

incus - Latin = anvil, hence the anvil-shaped ossicle of the middle ear.

index - Latin = a pointer, hence, the fore-finger.

Indicis - (L. index, one that points). The forefinger or pointer.

indicis - genitive of Latin index = a pointer, hence, of the fore-finger.

induced-fit model - describes how enzymes work.

indusium - Latin = tunic.

Inferior - (L. inferior, lower). Lower, caudal. adjective, Latin = lower down, hence, farther from the head end.

Infra- - (L. infra, below) Pertaining to a position below a named structure, e.g., infraspinatus.

Infrared - Denoting thermal radiation of wavelength greater than that of the red end of the spectrum (the recorded band of wavelengths of electromagnetic vibrations of variable light).

Infundibulum - Any of various funnel-shaped organs or parts.

inguinal - adjective, Latin inguen = groin.

inhibition - Latin inhibitus = restrained, hence, reduction of the excitability of a synapse.

innervate - Latin in = into, and nervus = nerve, hence, to supply a nerve to a part.

innominate - Lain in = not, and nomen = name, hence, without a name.

inorganic compound - compounds that do not contain carbon atoms. Water, O2, and NaCl are examples of inorganic compounds.

insert - Latin insertio = to join into, implant, hence, to attach; noun - insertion.

insertion - the muscle end that attaches to the moving structure.

inspection - Latin inspectus = examined, hence, visual examination.

insula - Latin = island.

Insulin - A hormone that helps the body use glucose (sugar) for energy.

integrator - a control center (often the brain).

integument - Latin in = on, tegmen = roof, hence the skin coat. enlarged or swollen lymph nodes.

integumentary system - the skin and its accessory organs.

Inter - (L. inter, between). Between or among.

interatrial septum - separates the left and right atria longitudinally in the heart.

intercalated - adjective, Latin inter = between, and calatum = inserted, hence interposed.

interdigitate - Latin inter = between, and digitus = a digit. Hence, to interlock like fingers.

Internal - (L. internus, interior). Deep or away from the surface. adjective, Latin internus = inward, hence, nearer the inside.

internuncial - adjective, Latin inter = between, nuncius = messenger.

interstitial - adjective, Latin inter = between, and sistum = set, hence, set between.

interventricular septum - separates the left and right ventricles longitudinally in the heart.

intestine - Latin intestinum = the digestive tube beyond the stomach.

intima - Latin = innermost.

intra - Latin = within.

Intraepithelial - Within the layer of cells that forms the surface or lining of an organ.

intrafusal - adjective, Latin intra = within, fusus = spindle.

intrinsic - adjective, Latin = on the inside.

introitus - Latin intro = within, and ire = to go, hence, an orifice or point of entry to a cavity or space.

inversion - Lain in = in, and vertere = to turn, hence to turn inward, inside out, upside down.

Ionizing radiation - Corpuscular (e.g., neutrons, electrons) or electromagnetic (e.g., gamma) radiation of sufficient energy to ionise the irradiated material.

Ipsilateral - Situated or appearing on or affecting the same side of the body.

ipsilateral - Latin ipsi = self, the same, and latus = side, hence on the same side.

iris - the colored portion of the eye that opens and closes to control the size of its circular opening, the pupil.

iris - Latin = a rainbow.

Ischio- - (G. ischion, hip) Pertaining to the ischium. á

ischium - Greek ischion = socket, because the ischium contributes more than either the ilium or pubis to the acetabulum.

Islets of Langerhans - Also called ISLANDS OF LANGERHANS, irregularly shaped patches of endocrine tissue located within the pancreas of most vertebrates. They are named for the German physician Paul Langerhans, who first described them in 1869. The normal human pancreas contains about 1,000,000 islets.

iso - Greek = equal.

Isotope - A form of a chemical element which varies from other forms of this element by the number of neutrons in it's nucleus. An isotope can be stable or radioactive depending upon the composition of its nucleus.

isthmus - Greek isthmos - a narrow passage.