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Medical Dictionary


filamentum, pl .filamenta (fil-a-men′tum, -ta)
A fibril, fine fiber, or threadlike structure. SYN: filament (1) . [L.]

filar (fi′lar)
1. SYN: fibrillar. 2. SYN: filamentous. [L. filum, a thread]

Filaria (fi-lar′e-a)
Former genus of nematodes now classified in several genera and species of the family Onchocercidae; e.g., Wuchereria bancrofti (F. bancrofti, F. diurna, or F. nocturna), Brugia malayi (F. malaya), Onchocerca volvulus (F. volvulus), Mansonella perstans (F. perstans or F. sanguinis hominis), M. streptocerca, M. ozzardi (F. demarquayi or F. ozzardi), Loa loa (F. extraocularis, F. lentis, F. loa, or F. oculi humani), and Dracunculus medinensis (F. medinensis) SEE ALSO: f..

filaria, pl .filariae (fi-lar′e-a, -e-e)
Common name for nematodes of the family Onchocercidae, which live as adults in the blood, tissue fluids, tissues, or body cavities of many vertebrates. The females lay partially embryonated eggs, the embryos uncoil and circulate in blood or tissue fluids as microfilariae; if ingested by an appropriate bloodsucking arthropod, larval stages develop; later, infective larvae may be deposited on another vertebrate host's skin when the arthropod seeks another blood meal. [L. filum, a thread]

filarial (fi-la′re-al)
Pertaining to a filaria (or filariae), including the microfilaria stage.

filariasis (fil-a-ri′a-sis)
Presence of filariae in the tissues of the body or in blood (microfilaremia) or tissue fluids (microfilariasis), occurring in tropical and subtropical regions; living worms cause minimal tissue reaction, which may be asymptomatic, but death of the adult worms leads to granulomatous inflammation and permanent fibrosis causing obstruction of the lymphatic channels from dense hyalinized scars in the subcutaneous tissues; the most serious consequence is elephantiasis or pachyderma. bancroftian f. f. caused by Wuchereria bancrofti. Brug f. infection with filarial organism Brugia malayi, which causes adenitis, fever, lymphangitis, and sometimes elephantiasis; occurs primarily in southeast Asia, India, Indonesia, China, Japan, Korea, and the Philippines. periodic f. a form of f. in which microfilariae appear in the peripheral blood at regular 24-hr intervals; usually refers to the nocturnal periodicity of bancroftian f..

filaricidal (fi-lar-i-si′dal)
Fatal to filariae.

filaricide (fi-lar′i-sid)
An agent that kills filariae. [filaria + L. caedo, to kill]

filariform (fi-lar′i-form)
1. Resembling filariae or other types of small nematode worms. SEE ALSO: f. larva. 2. Thin or hairlike.

Filariicae (fi-lar′e-i-se)
SYN: Filarioidea.

Filarioidea (fi-lar′e-oy′de-a)
A superfamily of filarial nematodes parasitic in many animal species, including man; includes the families Filariidae, Diplotraenidae, Onchocercidae, and Stephanofilariidae. See Filaria. SEE ALSO: Dipetalonema, Dirofilaria, Loa loa, Mansonella, Onchocerca, Wuchereria, Brugia. SYN: Filariicae.

Nil F., Russian pediatrician, 1847–1902. See F. disease.

Vladimir P., Russian ophthalmologist, 1875–1956. See F. flap, F.-Gillies flap.

file (fil)
A tool for smoothing, grinding, or cutting. Hedström f. a coarse root canal f. similar to a rasp. periodontal f. an instrument with a series of ridges or points arranged in rows on its surface, used for scaling or removing dental calculus from the teeth. root canal f. a pointed, flexible, steel intracanal instrument used in rasping canal walls.

filial (fil′e-al)
Denoting the relationship of offspring to parents. See f. generation. [L. filialis, fr. filius, son, filia, daughter]

filiform (fil′i-form)
1. SYN: filamentous (1) . 2. In bacteriology, denoting an even growth along the line of inoculation, either stroke or stab. [L. filum, thread]

filiform adnatum
SYN: ankyloblepharon.

filioparental (fil′e-o-pa-ren′tal)
Pertaining to a child-parent relationship. [L. filius, son, + parens, parent, fr. pario, to give birth]

fillet (fil′et)
1. SYN: lemniscus. 2. A skein, loop of cord, or tape used for making traction on a part of the fetus. [Fr. filet, a band] lateral f. SYN: lateral lemniscus. medial f. SYN: medial lemniscus.

filling (fil′ing)
Lay term for a dental restoration.

film (film)
1. A thin sheet of flexible material coated with a light-sensitive or x-ray–sensitive substance used in taking photographs or radiographs. 2. A thin layer or coating. 3. A radiograph (colloq.). absorbable gelatin f. a sterile, nonantigenic, absorbable, water-insoluble, thin sheet of gelatin prepared by drying a gelatin-formaldehyde solution on plates; used in the closure and repair of defects in membranes such as the dura mater or the pleura; it undergoes absorption over a period of 1–6 months. bitewing f. a special packaging of radiographic f. that allows an appendage of the f. package to be held between the occlusal surfaces of the teeth. decubitus f. a radiograph exposed with the subject in the decubitus position, named for the side that is dependent. SYN: right or left lateral decubitus f.. horizontal beam f. a radiograph made with the central axis of the x-ray beam parallel to the floor, able to show an air-fluid level. latitude f. SYN: wide-latitude f.. panoramic x-ray f. in dentistry, a radiograph taken to give a panoramic view of the entire upper and lower dental arch as well as the temporomandibular joints. plain f. a radiograph made without use of a contrast medium. precorneal f. a protective f., 7 to 9 nm thick, consisting of external oily, intermediate watery, and deep mucoprotein layers. SYN: tear f.. right or left lateral decubitus f. SYN: decubitus f.. scout f. a radiograph exposed before contrast medium is given, such as the preliminary f. for an angiogram, urogram, or barium contrast gastrointestinal examination. SYN: scout radiograph. f. speed the relative sensitivity of f. emulsion to light or radiation exposure; speed is inversely related to detail resolution. spot f. a radiograph made during the course of an examination under fluoroscopic control, with a device attached to the fluoroscope. tear f. SYN: precorneal f.. wide-latitude f. f. that does not show large contrast differences with differences in exposure; the slope of the H and D curve is low. SYN: latitude f..

film changer
A device that moves film for radiographic studies that require rapid serial x-ray exposures, such as angiography. SYN: rapid f., serial f.. rapid f. SYN: f.. serial f. SYN: f..

David L., U.S. biochemist, *1932. See Adair-Koshland-Némethy-F. model, Koshland-Némethy-F. model.

filopodia (fil-o-po′de-a)
Plural of filopodium.

filopodium, pl .filopodia (fi-lo-po′de-um, -a)
A slender filamentous pseudopodium of certain free-living amebae. [L. filum, thread, + G. pous, foot]

filopressure (fi-lo-presh′ur)
Temporary pressure on a blood vessel by a ligature, which is removed when the flow of blood has ceased. [L. filum, thread]

filovaricosis (fi′lo-var-e-ko′sis)
A series of swellings along the course of the axon of a nerve fiber. [L. filum, thread, + varix, dilation of vein]

Filoviridae (fi′lo-vi′ra-da)
A family of filamentous, single-stranded, negative sense RNA viruses with an enveloped nucleocapsid. These viruses were formerly classified with the Rhabdoviridae and are associated with hemorrhagic fever. The natural reservoir of these viruses is unknown. See Ebola virus. [L. filum, thread, + virus]

Filovirus (fi′lo-vi-rus)
A genus in the family Filoviridae that includes Marburg and Ebola viruses.

filter (fil′ter)
1. A porous substance through which a liquid or gas is passed in order to separate it from contained particulate matter or impurities to sterilize. SYN: filtrum. 2. To use or to subject to the action of a f.. 3. In diagnostic or therapeutic radiology, a plate made of one or more metals such as aluminum and copper which, placed in the x- or gamma ray beam, permits passage of a greater proportion of higher-energy radiation and attenuation of lower-energy and less desirable radiation, raising the average energy or hardening the beam. 4. A device used in spectrophotometric analysis to isolate a segment of the spectrum. 5. A mathematical algorithm applied to image data for the purpose of enhancing image quality, usually by suppression or enhancement of high spatial frequencies. 6. A passive electronic circuit or device that selectively permits the passage of certain electrical signals. 7. A device placed in the inferior vena cava to prevent pulmonary embolism from low extremity clot. There are many variants. [Mediev. L. filtro, pp. -atus, to strain through felt, fr. filtrum, felt] bandpass f. a device that allows a limited range of frequencies to pass. Berkefeld f. a bacterial f. used in 1891, made of earth known as Kieselguhr taken from the name of the mine in Hanover, Germany, from which the earth was found. Ground water at this mine had a clear blue color suggesting the use of the earth as a f.. [Berkefield, name of owner of the mine] bird's nest f. a wire mesh inferior vena cava f.. Greenfield f. a multistrutted, spring-style vena cava f.. high-pass f. a device or material that allows high frequency signals to pass while attenuating other signals. low-pass f. a device or material with the opposite effect from a high-pass f.; most tissues act as low-pass filters of ultrasound signals. nitinol f. a vena cava f. made with a metal that springs into shape when warmed to body heat by the blood after catheter insertion. vena cava f. a f. used for interruption of inferior vena cava to prevent pulmonary embolism; e.g., Greenfield f.. SYN: venocaval f.. venocaval f. SYN: vena cava f..

filtrable, filterable (fil′tra-bl, fil′ter-a-bl)
Capable of passing a filter; frequently applied to smaller viruses and some bacteria.

filtrate (fil′trat)
That which has passed through a filter.

filtration (fil-tra′shun)
1. The process of passing a liquid or gas through a filter. 2. In radiology, the process of attenuating and hardening a beam of x- or gamma rays by interposing a filter (3) between the radiation source and the object being irradiated; inherent f. is that which is caused by the apparatus itself, such as the glass of an x-ray tube, without addition of a filter. SYN: percolation (1) . gel f. separation of molecular sizes by passage of a mixture through columns of beads of cross-linked dextrans or similar relatively inert material of a well-defined pore size range; the larger the molecule, the less time it spends in the interior of the beads, thus emerging earlier from the column than smaller molecules.

filtrum (fil′trum)
SYN: filter (1) . [Mediev. L.] Merkel f. ventriculi SYN: f. ventriculi. f. ventriculi a groove between the two prominences, in each lateral wall of the vestibule of the larynx, formed by the cuneiform and the arytenoid cartilages. SYN: Merkel f. ventriculi.

filum, pl .fila (fi′lum, -la) [TA]
A structure of filamentous or threadlike appearance. [L. thread] f. durae matris spinalis SYN: dural part of f. terminale. fila olfactoria [TA] SYN: olfactory nerves [CN I], under nerve. olfactory fila SYN: olfactory nerves [CN I], under nerve. radicular fila the small, individual fiber fascicles into which the roots of all of the spinal nerves and several cranial nerves (hypoglossus, vagus, oculomotorius) divide in fanlike fashion before entering or leaving the spinal cord or brainstem; the spinal dorsal root may divide into 8–12 such rootlets. SYN: fila radicularia [TA] , root filaments. fila radicularia [TA] SYN: radicular fila. f. of spinal dura mater SYN: dural part of f. terminale. terminal f. a long connective tissue (pia mater) strand extending from the extremity of the medullary cone to the inner aspect of the spinal dural sac (pial part of f. terminale [TA], f. terminale internum [TAalt]; stout strands of connective tissue attaching the spinal dural sac to the coccyx (dural part of f. terminale [TA], coccygeal ligament [TAalt], f. terminale externum [TAalt]. SYN: f. terminale [TA] , nervus impar, terminal thread. f. terminale [TA] SYN: terminal f.. f. terminale externum dural part of f. terminale. f. terminale internum pial part of f. terminale.

fimbria, pl .fimbriae (fim′bre-a, -bre-e)
1. [TA] Any fringelike structure. SYN: fringe. 2. SYN: pilus (2) . [L. fringe] f. hippocampi [TA] a narrow sharp-edged crest of white fiber matter, continuous with the alveus hippocampi, attached to the medial border of the hippocampus; composed of efferent fibers of the hippocampus that form the fornix, fibers of the hippocampal commissure, and septohippocampal fibers. SYN: f. of hippocampus [TA] , corpus fimbriatum (1) , tenia hippocampi. f. of hippocampus [TA] SYN: f. hippocampi. ovarian f. [TA] the longest of the fimbriae of the uterine tube; it extends from the infundibulum to the ovary. SYN: f. ovarica [TA] , infundibulo-ovarian ligament. f. ovarica [TA] SYN: ovarian f.. fimbriae tubae uterinae [TA] SYN: fimbriae of uterine tube. fimbriae of uterine tube [TA] the irregularly branched or fringed processes surrounding the ampulla at the abdominal opening of the uterine tube; most of the lining epithelial cells have cilia that beat toward the uterus. SYN: fimbriae tubae uterinae [TA] , laciniae tubae.

fimbriate, fimbriated (fim′bre-at, -a-ted)
Having fimbriae.

fimbriectomy (fim′bre-ek′to-me)
Excision of fimbriae. [L. fimbria, fringe, + G. ektome, excision]

fimbrin (fim′brin)
An actin-binding protein that cross-links adjacent filaments tightly to form parallel actin fibers in vertebrate cells. It assists in maintaining cell polarity and development. [L. fimbriae, threads, fibers, + -in]

fimbriocele (fim′bre-o-sel)
Hernia of the corpus fimbriatum of the oviduct. [L. fimbria, fringe, + G. kele, hernia]

fimbrioplasty (fim′bre-o-plas-te)
Corrective operation upon the tubal fimbriae. [L. fimbria, fringe, + G. plastos, formed]

A competitive inhibitor of steroid 5α-reductase, an intracellular enzyme that converts testosterone into 5α-dihydrotestosterone, a potent androgen; used in the treatment of benign prostatic hyperplasia; also used to treat male pattern baldness and to regrow hair.

Johann, German psychiatrist, *1873. See F. test.

A clinically significant observation, usually used in relation to one found on physical examination or laboratory test.

fineness (fin′nes)
A designator used to indicate the precious metal content of an alloy, 1000 fine being 24-carat or pure gold.

finger (fing′ger) [TA]
One of the digits of the hand. SYN: digitus manus [TA] . [A.S.] baseball f. an avulsion, partial or complete, of the long f. extensor from the base of the distal phalanx. SYN: drop f., hammer f., mallet f.. blubber f. SYN: erysipeloid. clubbed fingers clubbing. dead fingers SYN: acroasphyxia. drop f. SYN: baseball f.. fifth f. SYN: little f.. first f. SYN: thumb. fourth f. SYN: ring f.. hammer f. SYN: baseball f.. hippocratic fingers clubbing. index f. [TA] the second f. (the thumb being counted as the first). SYN: digitus (manus) secundus [II]&star, forefinger, index (1) , second f.. jerk f. SYN: trigger f.. little f. [TA] the little or fifth f.. SYN: digitus (manus) minimus [TA] , digitus auricularis, digitus (manus) quintus [V], fifth f.. lock f. SYN: trigger f.. mallet f. SYN: baseball f.. middle f. [TA] third f.. SYN: digitus (manus) medius [TA] , digitus (manus) tertius [III]&star, third f.. ring f. [TA] fourth f.. SYN: digitus anularis [TA] , digitus (manus) quartus IV&star, fourth f.. sausage fingers the thick, short fingers of acromegaly; symmetric, diffusely swollen fingers; an early change in systemic sclerosis. seal fingers SYN: erysipeloid. second f. SYN: index f.. snap f. SYN: trigger f.. spade fingers the course, thick fingers of acromegaly or myxedema. spider f. SYN: arachnodactyly. spring f. SYN: trigger f.. stuck f. SYN: trigger f.. third f. SYN: middle f.. trigger f. a condition in which the movement of the f. is arrested for a moment in flexion or extension and then continues with a jerk; results from localized swelling of the tendon that interferes with its gliding through the pulleys in the palm of the hand. SYN: jerk f., lock f., snap f., spring f., stuck f.. waxy fingers SYN: acroasphyxia. webbed fingers two or more fingers united and enclosed in a common sheath of skin. whale fingers SYN: erysipeloid. white fingers an occupational disease occurring in operators of pneumatic hammers who are exposed to cold. zinc f. a zinc-binding domain in a protein structure often seen in certain gene regulatory proteins, e.g., transcription factors.

fingernail (fing′ger-nal)
See nail.

fingerprint (fing′ger-print′)
1. An impression of the inked bulb of the distal phalanx of a finger, showing the configuration of the surface ridges, used as a means of identification. SEE ALSO: dermatoglyphics, Galton system of classification of fingerprints. 2. Term, sometimes used informally, referring to any analytic method capable of making fine distinctions between similar compounds or gel patterns; e.g., the pattern of an infrared absorption curve or of a two-dimensional paper chromatograph. 3. In genetics, the analysis of DNA fragments to determine the identity of an individual or the paternity of a child. SYN: genetic f.. Galton system of classification of fingerprints a system of classification based on the variations in the patterns of the ridges, which are grouped into arches, loops, and whorls (A.L.W. or arch-loop-whorl system). “Arches are formed when the ridges run from one side to the other of the bulb of the digit, without making any backward turn, but no twist; whorls, when there is a turn through at least one complete circle; they are also considered to include all duplex spirals.” The abbreviations used in making a record of fingerprints are: a, arch; l, loop; w, whorl; i, loop with an inner (thumb side) slope; o, loop with an outer (little-finger side) slope. The ten digits are registered in four groups as follows, distinguished by capital letters: A, the fore, middle, and ring fingers of the right hand; B, the fore, middle, and ring fingers of the left hand; C, the thumb and little finger of the right hand; D, the thumb and little finger of the left hand. SEE ALSO: dermatoglyphics. genetic f. SYN: f. (3) .

finger spelling
A system of communication with a profoundly hearing impaired person by spelling words in which the letters of the alphabet are represented by positions of the fingers.

R.P., 20th century U.S. anatomist. See F.-Heimer stain.

Wilhelm, 20th century German pathologist. See Warthin-F. cells, under cell.

John M.T., U.S. surgeon, 1863–1942. See F. operation, F. pyloroplasty.

fire (fir)
In dentistry, the fusing of water and a powder containing kaolin, feldspar, and other substances to produce porcelain used in restorations and artificial teeth.

firedamp (fir′damp)
Methane or other light hydrocarbons forming an explosive mixture when mixed with 7 or 8 volumes of air.

first aid
Immediate assistance administered in the case of injury or sudden illnes by a bystander or other lay person, before the arrival of trained medical personnel.

Louis, U.S. pediatrician, 1864–1945. See F. sign, F. symptom.

Emil, German chemist and Nobel laureate, 1852–1919. See F. projection formulas of sugars, Kiliani-F. synthesis, Kiliani-F. reaction.

Arthur M., U.S. physician, *1898. See F. concentration test.

fish berry
The seeds of Anamirta paniculata which contain the amaroid, picrotoxin; a CNS and respiratory stimulant, used in veterinary medicine as an antidote to barbiturates. Name derived from the use of bruised berries thrown into streams to poison or incapacitate fish.

Ronald A., British medical statistician and geneticist, 1890–1962; invented many statistical tests.

C. Miller, U.S. neurologist, *1910. See F. syndrome.

Fishman-Lerner unit
See under unit.

fission (fish′un)
1. The act of splitting, e.g., amitotic division of a cell or its nucleus. 2. Splitting of the nucleus of an atom. [L. fissio, a cleaving, fr. findo, pp. fissus, to cleave] binary f. simple f. in which the two new cells are approximately equal in size. bud f. SYN: gemmation. multiple f. division of the nucleus, simultaneously or successively, into a number of daughter nuclei, followed by division of the cell body into an equal number of parts, each containing a nucleus. simple f. division of the nucleus and then the cell body into two parts. SEE ALSO: binary f..

fissiparity (fis-i-par′i-te)
SYN: schizogenesis. [L. fissio, cleaving, fr. findo, to cleave, + pario, to bring forth]


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