F - Glossary of Terms

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F - Glossary of Terms

face	1 The anterior aspect of the head not supporting or covering the brain. 2 The exposed surface of a structure.
facet	(fas´et) A small, smooth surface of a bone where articulation occurs.
faeces	(fe´s-ez) Material expelled from the GI tract during defecation, composed of undigested food residue, bacteria, and secretions; also called stool.
Fahrenheit	(fah'ren-hit). Pertaining to thermometric scale invented by Gabriel Daniel Fahrenheit. On Fahrenheit thermometer, freezing point of water is 32° above zero point, and boiling point of water at 212°. Cf. centigrade.
falciform ligament	(fal´si-form lig´a-ment) An extension of parietal peritoneum that separates the right and left lobes of the liver.
falling-load generator	A design in which exposure factors are automatically adjusted to the highest mA at the shortest exposure time allowed by the high-voltage generator.
fallopian tube	(fa-lo´pe-an) See uterine tube.
false vocal cords	The supporting folds of tissue for the true vocal cords within the larynx.
falx cerebelli	(falks ser´´e-bel´e) A fold of the dura mater anchored to the occipital bone. It projects inward between the cerebellar hemispheres.
falx cerebri	(ser´e-bre) A fold of dura mater anchored to the crista galli of the ethmoid bone. It extends between the right and left cerebral hemispheres.
fan beam	X-ray beam pattern used in computed tomography and digital radiograph; projected as a slit.
fascia	(fash´e-a) Two meanings:1. Superficial fascia:Loose connective and fatty tissue, of variable thickness (prevertebral) 2. Deep fascia:A tough sheet of fibrous tissue binding the skin to underlying muscles or supporting and separating muscles. (clavipectoral)
fascia lata	deep fascia of the thigh
fasciculus	(fa-sik´yuu-lus) A small bundle of muscle or nerve fibers.
fauces	(faw´s-ez) Latin = throat, the passageway between the mouth and the pharynx.
febrile	(fe'brile). Pertaining to fever; feverish.
fecal	(fe'kal). Relating to or of nature of feces.
feces	(fe'sez). Excrement, or waste products, of food digestion discharged from bowels.
feed tray	The start of the transport system where the film to be processed is inserted into the automatic processor in the darkroom.
fenestra	(fe-nes'trah). Small aperture, or opening, as in certain bones.
ferromagnetic material	Material that is strongly attracted by a magnet and that can usually be permanently magnetised by exposure to a magnetic field.
fetid	(fe'tid) Having offensive smell.
fetography	(fe-tog'ra-fe) Radiographic examination of fetus in utero.
fibrin	(fi´brin) The insoluble protein formed from fibrinogen by the enzymatic action of thrombin during the process of blood clot formation.
fibrinolysis	Breaking up of a blood clot.
fibroma	(fi-bro'mah). Benign tumor composed mainly of fibrous tissue.
fibrosis	(fi-bro'sis). Formation of fibrous tissue in any organ or region; replacement of normal tissue with fibrous tissue.
fibrous joint	(fi´brus) A type of articulation bound by fibrous connective tissue that allows little or no movement (a synarthrosis). (see syndesmosis, suture, gomphosis)
fibular	Can be used to mean lateral side of the leg (see tibial, peroneal)
field	The interactions among different energies, forces, or masses that cannot be seen but can be described mathematically.
field of view (FOV)	The image matrix size provided by digital x-ray imaging systems.
fifteen-percent rule	A principle stating that if the optical density on a radiograph is to be increased using kVp, an increase in kVp by 15% is equivalent to doubling the mAs.
filament	The part of the cathode that emits electrons, resulting in a tube current.
file	A collection of data or information that is treated as a unit by the computer.
filiform papillae	(fil´i-form pa-pil´e) Numerous small projections over the entire surface of the tongue in which taste buds are absent.
film badge	A pack of photographic film used for approximate measurement of radiation exposure to radiation workers. It is the most widely used and most economical type of personnel radiation monitor. also see TLD thermoluminescent device.
film contrast	The contribution to the overall radiographic contrast from the intensifying screen-film processing system visualised in a processed radiograph. Film contrast usually increases the subject contrast (i.e., gamma is greater that one) as the system converts the X-ray intensity variations emergent from the subject into visible images.
film density	See optical density.
film gradient	A measure of the slope of characteristic curve at any point.
film graininess	A type of radiographic mottle caused by the size of the individual silver-halide crystals and their tendency to clump during development.
film speed	A measure of the exposure necessary to produce an optical density of 1.0 above base plus fog. Usually expressed in relative percentage of a par speed system (200, 400, etc.).
filtered back projection	The process by which an image acquired during computed tomography and stored in computer memory is reconstructed.
filtration	The removal of low-energy X-rays from the useful beam with aluminum, copper or another metal. It results in increased beam quality and reduced patient dose.
filum terminale	(fi´lum ter-mi-nal´e) A fibrous, threadlike continuation of the pia mater, extending inferiorly from the terminal end of the spinal cord to the coccyx.
fimbriae	(fim´bre-e) Latin = a fringe, fringe like extensions. (e.g. open end of the uterine tube)
first-generation computed tomographic scanner	A finely collimated x-ray beam, single-detector assembly that translates across the patient and rotates between successive translations.
fissure	(fish´ur) A groove or narrow cleft that separates two parts, such as the cerebral hemispheres of the brain.
fistula	(fis'tu-lah) Abnormal passage leading from an abscess cavity or from a hollow organ to surface of body or from one hollow organ to another.
five-percent rule	A principle stating that an increase of 5% in the kVp may be accompanied by a 30% reduction in the mAs to produce the same optical density at a slightly reduced contrast scale.
fixation	The removal of undeveloped silver halide grains after development of the film to prevent slow darkening, which would otherwise occur as the silver ions are gradually, naturally reduced over time.
fixing	The stage of processing during which the silver halide not exposed to radiation is dissolved and removed from the emulsion.
flaccid	(flas'sid). Without firmness or tone; flabby, as a flaccid muscle.
flagellum	(fla-jel´um) A whip like structure that provides motility for sperm.
flatulence	(flat'u-lens). Gaseous distention of stomach or intestines.
flatus	(fla'tus). Gas generated in stomach or intestines and passed through the rectum
flexion	(flek´shun) A movement that decreases the angle between parts of a joint, opposite of extension.
flexor	(flek´sor) A muscle that decreases the angle of a joint when it contracts.
flocculent	(flok'u-lent). Containing soft flakes or shreds, as in a flocculent precipitate.
fluorescence	The emission of visible light only during stimulation.
fluorescent screen	The cycle in a television-picture tube when the electron beam creates the television optical signal and then immediately fades.
fluoroscope	Device used to image moving anatomic structures with X-rays.
fluoroscopy	An imaging modality that provides a continuous image of the motion of internal structures while the x-ray tube is energised. Real-time imaging.
flux	(fluks) Flow of either energy or a liquid; an excessive discharge, as from the bowels.
flux gain	The ratio of the number of light photons at the output phosphor to the number of X-rays at the input phosphor.
focal	Localised.
focal distance	In a focused grid, the perpendicular distance between the grid and the convergent line or point.
focal plane	Plane of tissue that is maximumly in focus on a tomogram.
focal plane level	Height from level of focal plane to tabletop.
focal spot	The region of anode target where electrons interact to produce X-rays.
focal-spot blur	A blurred region on the radiograph over which the radiographer has little control.
focused grid	A radiographic grid constructed so that the grid strips converge on an imaginary line.
focusing cup	A metal shroud surrounding the filament.
foetus	(fe´tus) A prenatal human after 8 weeks of development.
fog	An unintended optical density on a radiograph that reduces contrast because of light or chemical contamination.
fog density	The development of silver grain that contains no useful information.
fogging	A background gray level added to radiographs due to exposure to some type of undesired non-information carrying radiation, e.g., light in the darkroom or scattered X-rays. Fogging also results from film processing.
fontanel	(fon´´ta-nel´) A membranous-covered region on the skull of a fetus or baby where ossification has not yet occurred; commonly called a soft spot.
foot	The terminal portion of the lower extremity, consisting of the tarsal bones, metatarsal bones, and phalanges.
foramen	(fo-ra´men), pl. foramina An opening in an anatomical structure, usually in a bone, for the passage of a blood vessel or a nerve.
foramen ovale	(o-val´e) An opening through the interatrial septum of the fetal heart.
force	That which changes the motion of an object; a push or a pull. Expressed in newtons (N).
forearm	The portion of the upper extremity between the elbow and the wrist; also called the antebrachium. (see arm, brachium)
foreshortening	The reduction in image size; related to the angle of inclination of the object.
formula	(for'mu-lah). Prescribed ingredients, with proportions, for preparation of a medicine; prescription; combination of symbols to express chemical constituents of a body.
fornix	(for´niks) Latin = arch:1.A recess around the cervix of the uterus where it protrudes into the vagina. 2.A tract within the brain connecting the hippocampus with the mammillary bodies.
fossa	(fos´a) A pit, cavity, or depression; as acetabular fossa, supraclavicular fossa, and nasal fossae.
4% voltage ripple	Three-phase, 12-pulse power whose voltage supplied to the X-ray tube never falls below 96% of the peak value.
14% ripple	Three-phase, six pulse power whose volt¬age supplied to the X-ray tube never falls below 86% of the peak value.
fourth-generation computed tomographic scanner	A unit in which the X-ray source rotates but the detector assembly does not.
fourth ventricle	(ven´tri-k'l) A cavity within the brain, between the cerebellum and the medulla oblongata and the pons, containing cerebrospinal fluid.
fovea	(fo've-ah). Pit or cup-shaped depression
fovea centralis	(fo´ve-a sen-tra´ lis) Latin = a pit (usually smaller than a fossa), a depression on the macula lutea of the eye, where only cones are located; the area of keenest vision.
Fowler's position	(fowlerz). Position in which head end of body is elevated, usually about 30 degrees.
fraction	A numerical value expressed by dividing one number by another.
fractionated	A radiation dose delivered at the same dose in equal portions at regular intervals.
Frankfurt plane or line	See anthropologic base line.
free radical	An uncharged molecule containing a single unpaired electron in the valence shell.
fremitus	(frem'i-tus) Palpable vibration or thrill; as tussive fremitus, vibration felt through head on humming with mouth closed.
frenulum	(fren´yuu-lum) Latin = bridle or curb:a membranous structure that serves to anchor and limit the movement of a body part.
frequency	The number of cycles or wavelengths of a simple harmonic motion per unit time. Expressed in Hertz (Hz). 1 Hz = 1 cycle/s.
frontal	Two meanings 1.Pertaining to the region of the forehead. 2. A plane through the body, dividing the body into anterior and posterior portions; also called the coronal plane.
fulcrum	Pivot point or axis about which tube and film rotate during a tomographic motion.
full-wave rectification	An X-ray tube circuit in which the negative portion of the AC cycle is electronically inverted, producing a circuit that varies between a potential of zero and a positive maximum with no negative portion.
full width at half maximum (FWHM)	The width of the profile at half its maximum value.
fundamental laws of motion	The three principles of inertia, force, and action/reaction established by Isaac Newton.
fundamental particles	The three primary constituents of an atom: electrons, photons, and neutrons.
fundus	Latin = bottom or base. ). Base or deepest part of a hollow organ.
fungiform papillae	(fun´gi-form pa-pil´e) Flattened, mushroom-shaped projections interspersed over the surface of the tongue in which taste buds are present.
furuncle	(fur'nun-cal). A boil; a localized, pus-filled skin infection.
fusiform	Spindle shaped.

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