flail chest A condition that occurs when enough ribs are broken (usually from a crush injury) to compromise the rigidity of the chest wall. On inspiration, the chest wall moves inward instead of outward, and it does the opposite on expiration.
five-day fever See trench fever.
fistula An abnormal passageway between organs, vessels, or other structures that are not normally connected. For example, an anal fistula is an opening in the skin near the anus: This opening may lead to a tunnel into the rectal canal or to a passage that ends in a blind pouch.
fish-odor syndrome An inborn error of metabolism that is associated with an offensive body odor whose scent is similar to the smell of rotting fish. Fish-odor syndrome is due to the excessive excretion of trimethylamine (TMA) in urine, sweat, and breath. This syndrome is caused by a mutation in the gene for the enzyme flavin-containing…
Fisher’s exact test A statistical test used to determine whether there is a nonrandom association between two variables that is much used in medical research. It tests the independence of rows and columns in a 2 × 2 contingency table (a table with two horizontal rows crossing two vertical columns, creating four places for data)…
fishbowl granuloma See granuloma, fishbowl.
FISH Fluorescence in situ hybridization, a molecular cytogenetic technique that tags genetic material with fluorescent molecules. FISH is useful for identifying chromosomes and parts of chromosomes, deciphering chromosome rearrangements, detecting chromosome abnormalities, and detecting and mapping genes. For example, a FISH probe to chromosome 21 allows the detection of cells with trisomy 21 (an extra…
first stage of labor The part of labor when the cervix dilates fully, to approximately 10 centimeters in diameter. Also known as the stage of dilatation.
first do no harm A classic slogan that is used in medicine, often in the Latin wording primum non nocere that is attributed to Hippocrates.
fire supplies kit See disaster supplies.
fire ant Originally from South America, a red or yellowish ant of small to medium size that has a severe sting that burns like fire. The sting of a fire ant causes a pustule to form within 24 hours that takes several days to resolve. Fire ant toxin can trigger an allergic reaction, particularly in…
fire, St. Anthony’s An intensely painful burning sensation in the limbs and extremities that is caused by ergot, which is the consequence of a fungus (Claviceps purpurea) that contaminates rye and wheat. See also ergot.