Medical terms - Letter I (page 4) | MedicalVocabulary.org

Implantation

The act of setting in firmly. In embryology, implantation refers specifically to the attachment of the fertilized egg to the uterine lining, which occurs approximately 6 or 7 days after conception (fertilization). In…
Implantation, seed

Radiation treatment given by placing radioactive material contained within a small cylindrical shell directly in or near the target, often a tumor
Implicit memory

Memory characterized by a lack of conscious awareness in the act of recollection. By contrast, explicit memory requires conscious recollection of previous experience. Implicit memory may survive largely unimpaired at…
Impotence

Impotence: A common problem among men characterized by the consistent inability to sustain an erection sufficient for sexual intercourse or the inability to achieve ejaculation, or both. Impotence can vary. It can…
Imprinting, genomic

The phenomenon of parent-of-origin gene expression. The expression of a gene depends upon the parent who passed on the gene. For instance, two different disorders - Prader-Willi syndrome and Angelman syndrome -- are due…
Imprinting, psychological

A remarkable genetic phenomenon that occurs in animals, and theoretically humans, in the first hours of life. The newborn creature bonds to the type of animals it meets at birth, and begins to pattern its behavior after…
Impulsivity

Inclined to act on impulse rather than thought. People who are overly impulsive, seem unable to curb their immediate reactions or think before they act. As a result, they may blurt out answers to questions or…
IMRT

Intensity modulated radiation therapy
In

Abbreviation for inch
In situ

In the normal location. An 'in situ' tumor is one that is confined to its site of origin and has not invaded neighboring tissue or gone elsewhere in the body. For example, squamous cell carcinoma in situ is an early…
In situ hybridization

The use of a DNA or RNA probe to detect the complementary sequence. In situ hybridization is like all nucleic acid hybridization in being a technique in which single-stranded nucleic acids (DNA or RNA) are permitted to…
In situ hybridization, fluorescent

An important molecular cytogenetic method for identifying chromosomes and parts of chromosomes, deciphering chromosome rearrangements, and locating genes on chromosomes. 'Fluorescent' means emitting light that comes…
In situ, carcinoma

Cancer that involves only the place in which it began and has not spread. Carcinoma in situ is an early-stage tumor. For example, squamous cell carcinoma in situ (Bowen's disease) is an early cancer of the skin. It…
In vitro

Literally in glass, as in a test tube. A test that is performed in vitro is one that is done in glass or plastic vessels in the laboratory. In vitro is the opposite of in vivo (in a living organism).
In vitro fertilization

In the living organism, as opposed to in vitro (in the laboratory).
In vivo

In the living organism, as opposed to in vitro (in the laboratory).
In-law

A relative by marriage. An in-law is not a biologic relative. This distinction is of importance in a medical family history
In-the-canal hearing aid

A hearing instrument custom designed to fit in the ear canal. It protrudes slightly into the outer ear and so is visible. In-the-canal (ITC) instruments are appropriate for mild to moderate hearing losses but not for…
In-the-ear hearing aid

A hearing instrument in a custom-made shell designed to fit in the outer ear and ear canal. An in-the-ear (ITE) aid may be suitable for mild to moderately severe hearing loss but not for infants or young children. See…
Inactivation, X chromosome

A syndrome of inappropriate secretion of antidiuretic hormone (ADH) which results in the inability to put out dilute urine, perturbs fluid (and electrolyte) balance, and causes nausea, vomiting, muscle cramps, confusion…
Inappropriate ADH secretion

A syndrome of inappropriate secretion of antidiuretic hormone (ADH) which results in the inability to put out dilute urine, perturbs fluid (and electrolyte) balance, and causes nausea, vomiting, muscle cramps, confusion…
Inborn error of metabolism

A heritable disorder of biochemistry. Examples of inborn errors of metabolism include albinism, cystinuria (a cause of kidney stones), phenylketonuria (PKU), and some forms of gout, sun sensitivity, and thyroid disease…
Inbreeding

The mating of two closely related persons. Also called consanguinity.
Inbreeding, coefficient of

A measure of how close two people are genetically to each another. The coefficient of inbreeding, symbolized by the letter F, is the probability that a person with two identical genes received both genes from one…
Incase

A term once used to refer to the medical case of an inpatient
Incest

Sexual activity between individuals so closely related that marriage is prohibited. Incest involving a child is a form of child abuse.
Inch

In length, 1/12th of foot or 1/36 of a yard or, metrically, 2.54 centimeters. The inch, along with the foot and yard, are Old World creations to which the USA has stubbornly clung. The inch was originally about the…
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…
Incision

A cut. When making an incision, a surgeon is making a cut.
Incisional biopsy

A biopsy in which only a sample of the suspicious tissue is cut into (incised) and removed for purposes of diagnosis. A incisional biopsy is in contrast to an excisional biopsy in which an entire lesion, usually a…
Incompatibility, Rh

The state of mother and fetus having different Rh blood group types so that their Rh types are 'incompatible.' The red blood cells of an Rh+ (Rh positive) fetus may in this situation be attacked by antibodies produced…
Incompetent cervix

A cervix that is abnormally liable to dilate and so is not competent to keep the fetus up in the uterus and keep it from being spontaneously aborted (miscarried)
Inconclusive clinical trial

A clinical trial that shows that a new treatment is neither clearly superior nor clearly inferior to standard treatment. See: Clinical trials. See also: Negative clinical trial; Non-inferior clinical trial; Positive…
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.
Incontinence of urine

Inability to hold urine in the bladder. This is due to failure of voluntary control over the urinary sphincters resulting in involuntary passage of urine (wetting). See enuresis. See also bedwetting
Incontinence, fecal

Inability to hold feces in the rectum. This is due to failure of voluntary control over the anal sphincters permitting untimely passage of feces and gas. Also called rectal incontinence
Incontinence, rectal

Inability to hold feces in the rectum due to failure of voluntary control over the anal sphincters with involuntary passage of feces and gas. Also called fecal incontinence
Incontinence, urge

A sudden involuntary contraction of the muscular wall of the bladder causing urinary urgency, an immediate unstoppable urge to urinate. It is a form of urinary incontinence (the unintentional loss of urine) and affects…
Incontinence, urinary

Incontinence, urinary: The unintentional loss of urine. Inability to hold urine in the bladder due to loss of voluntary control over the urinary sphincters resulting in the involuntary passage of urine. One cause of…
Incontinent

Unable to control excretions, to hold urine in the bladder or keep feces in the rectum. This is the usual medical meaning of the word incontinent. Incontinent can also refer to a lack of self-restraint in the sexual…
Incontinentia pigmenti

In medicine, the time from the moment of exposure to an infectious agent until signs and symptoms of the disease appear. For example, the incubation period of chickenpox is 14-16 days. In biology, the incubation period…
Incubation period

In medicine, the time from the moment of exposure to an infectious agent until signs and symptoms of the disease appear. For example, the incubation period of chickenpox is 14-16 days. In biology, the incubation period…
Incubator

In biotechnology. an apparatus in which environmental conditions can be set and controlled. Incubators are used in microbiology for culturing (growing) bacteria and other microorganisms. Incubators in tissue culture…
Incurable

Not amenable to a cure. Incapable of being cured, healed and made well again. Many pancreatic cancers are incurable. From the word cure, from the Latin cura meaning care, concern or attention
Incus

One of the three tiny bones in the middle ear. Sound impulses coming from the eardrum are conveyed from the malleus to the incus and from the incus to the stapes at the oval window to the inner ear. Incus is Latin for…
Index case

A person who first draws attention to their family. For example, if my eye doctor discovers I have glaucoma and subsequently other cases of glaucoma are found in my family, I am the index case. Also called the…
Index, body mass (BMI)

An index that relates body weight to height. The body mass index (BMI) is obtained by dividing a person's weight in kilograms (kg) by their height in meters (m) squared. The National Institutes of Health (NIH) now…
Indian Health Service (IHS)

A part of the U.S. Public Health Service within the US Department of Health and Human Services, the Indian Health Service (IHS) is responsible for providing federal health services to American Indians and Alaska…
Indian meal moth

See: Meal moth
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…