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Medical Dictionary


focal (fo′kal)
1. Denoting a focus. 2. Relating to a localized area.

focal spot size
The measured size of a focal spot of an x-ray tube, a function of the actual size of the cathode and the angulation of the anode surface. See focal spot.

foci (fo′si)
Plural of focus.

focimeter (fo-sim′e-ter)
SYN: lensometer.

focus, pl .foci (fo′kus, fo′si)
1. (F) The point at which the light rays meet after passing through a convex lens. 2. The center, or the starting point, of a disease process. [L. a hearth] conjugate foci two points so related to a lens or concave mirror that an image at one point is focused at the other, and vice versa. Ghon f. SYN: Ghon tubercle. natural f. of infection an ecosystem in which an infectious agent normally persists in nature; e.g., yellow fever virus in a jungle monkey-Haemagogus mosquito ecosystem. principal f. the real or virtual meeting point of rays passing into a lens parallel to its axis. real f. the point of meeting of convergent rays. virtual f. the point from which divergent rays seem to proceed, or that at which they would meet if prolonged backward.

fodrin (fo′drin)
A spectrin-like protein that cross-links adjacent actin filaments in vertebrate cells.

Thomas J., U.S. thoracic surgeon, *1934. See F. embolectomy catheter, F. clamp.

fogging (fog′ing)
A method of refraction in which accommodation is relaxed by overcorrection with a convex spherical lens.

fogo selvagem (fo′go sel′va-jem)
A form of pemphigus foliaceus, occurring in southern Brazil, in which the lesions are bullous, appear localized to the face and upper trunk, become widespread, variegated, erythrodermic, and exfoliative, and are immunologically indistinguishable from pemphigus foliaceus or vulgaris. SYN: Brazilian pemphigus, wildfire. [Pg. wild fire]

foil (foyl)
An extremely thin pliable sheet of metal.

Charles, French neurologist, 1882–1927. See F.-Alajouanine myelitis, F.-Alajouanine syndrome, F.-Cavany-Marie syndrome.

folate (fo′lat)
A salt or ester of folic acid.

fold (fold) [TA]
1. A ridge or margin apparently formed by the doubling back of a lamina. SYN: plica. 2. In the embryo, a transient elevation or reduplication of tissue in the form of a lamina. adipose folds of the pleura SYN: fatty folds of pleura. alar folds of intrapatellar synovial f. [TA] winglike fat-filled lateral and medial fringes or expansions of the infrapatellar synovial f.. SYN: plicae alares plicae synovialis infrapatellaris. amnionic f. a f. of amnionic membrane enclosing the yolk stalk and extending from the point of insertion of the umbilical cord to the yolk sac; in reptiles and birds it is the reflected edge of the amnion where it folds over to cover the embryo during early development. SYN: Schultze f.. ampullary folds of uterine tube one of the folds of mucous membrane at the fimbriated extremity of the uterine tube. SYN: plicae ampullares tubae uterinae. anterior axillary f. bounds axilla anteriorly; formed by skin and fascia overlying inferior border of pectoralis major muscle. aryepiglottic f. [TA] a prominent f. of mucous membrane stretching between the lateral margin of the epiglottis and the arytenoid cartilage on either side; it encloses the aryepiglottic muscle. SYN: plica aryepiglottica [TA] , arytenoepiglottidean f.. arytenoepiglottidean f. SYN: aryepiglottic f.. axillary f. one of the folds of skin and muscular tissue bounding the axilla anteriorly and posteriorly. SYN: plica axillaris. caval f. a f. near the base on the right side of the dorsal mesentery, in which a primordial segment of the inferior vena cava develops between the right subcardinal vein and vessels within the liver. cecal folds [TA] the two peritoneal folds that border the retrocecal fossa. SYN: plicae cecales [TA] . f. of chorda tympani the f. of mucosa that surrounds the chorda tympani nerve in its course through the tympanic cavity. SYN: plica chordae tympani. ciliary folds [TA] a number of low ridges in the furrows between the ciliary processes; together with the processes they constitute the corona ciliaris. SYN: plicae ciliares [TA] . circular folds of small intestine [TA] the numerous folds of the mucous membrane of the small intestine, running transversely for about two-thirds of the circumference of the gut. SYN: plicae circulares intestini tenuis [TA] , Kerckring folds, Kerckring valves, valvulae conniventes. Dennie-Morgan f. a f. or line below both lower eyelids caused by edema in atopic dermatitis. SYN: Dennie line. dinucleotide f. a structural domain in certain proteins that binds NAD+ or NADP+. SYN: dinucleotide domain. Douglas f. SYN: rectouterine f.. Duncan folds the folds on the peritoneal surface of the uterus immediately after delivery. duodenojejunal f. superior duodenal f.. duodenomesocolic f. inferior duodenal f.. epicanthal f. SYN: palpebronasal f.. epigastric f. SYN: lateral umbilical f.. epiglottic folds one of the three folds of mucous membrane passing between the tongue and the epiglottis, lateral glossoepiglottic f. on either side, and median glossoepiglottic f. centrally. SYN: plicae epiglotticae. falciform retinal f. a congenital f. from the disk to the ciliary region in the inferior temporal quadrant of the retina. fatty folds of pleura lobules of fat enveloped in the pleura, chiefly in the neighborhood of the costomediastinal sinus. SYN: adipose folds of the pleura, plicae adiposae pleurae. fimbriated f. of inferior surface of tongue [TA] one of several folds running outward from the frenulum on the undersurface of the tongue. SYN: plica fimbriata faciei inferioris linguae [TA] . gastric folds [TA] characteristic folds of the gastric mucosa, especially evident when the stomach is contracted. SYN: plicae gastricae [TA] , gastric rugae&star, ruga gastrica, rugae of stomach. gastropancreatic folds [TA] the folds of peritoneum in the omental bursa that encase the hepatic and left gastric arteries as these vessels pass toward their destinations. SYN: plicae gastropancreaticae [TA] . genital f. SYN: urogenital ridge. giant gastric folds enlarged gastric submucosal ridges covered by hyperplastic mucosa, as seen in Zollinger-Ellison syndrome, Ménétrièr disease, and hypertrophic hypersecretory gastropathy. glossopalatine f. SYN: palatoglossal arch. gluteal f. [TA] a prominent f. that marks the upper limit of the thigh from the lower limit of the buttock; it coincides with the lower border of the gluteus maximus muscle; the furrow between the buttock and thigh. SYN: sulcus gluteus [TA] , gluteal furrow. Guérin f. SYN: valve of navicular fossa. Hasner f. SYN: lacrimal f.. head f. a ventral folding of the cephalic extremity in the embryonic disk, so that the brain lies rostrad to the mouth and pericardium. Houston folds SYN: transverse folds of rectum. ileocecal f. [TA] a f. of peritoneum bounding the ileocecal or ileoappendicular fossa. SYN: plica ileocecalis [TA] , Treves f.. incudal f. a variable f. of mucosa that passes from the roof of the tympanic cavity to the body and short limb of the incus. SYN: plica incudis. inferior duodenal f. [TA] a f. of peritoneum bounding the inferior duodenal recess. SYN: plica duodenalis inferior [TA] , duodenomesocolic f.&star, plica duodenomesocolica&star. infrapatellar synovial f. [TA] a f. of synovial membrane extending from below the level of the articular surface of the patella to the anterior part of the intercondylar fossa. SYN: plica synovialis infrapatellaris [TA] , plica synovialis patellaris. inguinal f. SYN: plica inguinalis. inguinal aponeurotic f. SYN: inguinal falx. interarytenoid f. the soft tissue between the arytenoid cartilages. SYN: posterior commissure of the larynx. interdigital folds SYN: web of fingers/toes. interureteric f. SYN: interureteric crest. folds of iris [TA] numerous very fine, almost microscopic, radial folds on the posterior surface of the iris that extend around the pupillary margin. SYN: plicae iridis [TA] . Kerckring folds SYN: circular folds of small intestine. Kohlrausch folds SYN: transverse folds of rectum. labioscrotal folds lateral folds at either side of the embryonic cloacal membrane that develop into either the scrotum or the labia majora. lacrimal f. [TA] a f. of mucous membrane guarding the lower opening of the nasolacrimal duct. SYN: plica lacrimalis [TA] , Hasner f., Huschke valve, Rosenmüller valve. f. of laryngeal nerve SYN: f. of superior laryngeal nerve. lateral folds ventral foldings of the lateral margins of the embryonic disk, the development of which helps establish the definitive embryonic body form. lateral glossoepiglottic f. [TA] the f. of mucous membrane that extends from the margin of the epiglottis to the pharyngeal wall and base of the tongue on each side, forming the lateral boundary of the epiglottic valleculae. SYN: plica glossoepiglottica lateralis [TA] , pharyngoepiglottic f.. lateral nasal f. SYN: lateral nasal prominence. lateral umbilical f. [TA] the ridge on the peritoneal surface of the anterior abdominal wall formed by the inferior epigastric vessels. SYN: plica umbilicalis lateralis [TA] , epigastric f., plica epigastrica. f. of left vena cava [TA] a pericardial f. lying between the left oblique vein of the atrium and the left superior pulmonary vein containing the obliterated remains of the left superior vena cava. SYN: plica venae cavae sinistrae [TA] , Marshall vestigial f., vestigial f.. longitudinal f. of duodenum [TA] a f. of mucosa on the medial wall of the descending part of the duodenum above the major duodenal papilla, probably caused by the relation to the common bile duct. SYN: plica longitudinalis duodeni [TA] . malar f. an ill-defined groove in the skin that extends downward and medially from the lateral canthus. mallear folds [TA] two ligamentous bands, anterior and posterior, making folds on the tympanic side of the tympanic membrane extending from each extremity of the tympanic notch to the malleolar prominence; they mark the boundary between the tense and the flaccid portions of the tympanic membrane. SYN: plicae malleares (anterior et posterior) [TA] , plica membranae tympani. mammary f. SYN: mammary ridge. Marshall vestigial f. SYN: f. of left vena cava. medial canthic f. palpebronasal f.. medial nasal f. SYN: medial nasal prominence. medial umbilical f. [TA] a f. of peritoneum on the lower part of the anterior abdominal wall that covers the obliterated umbilical artery on either side of the urachus. SYN: plica umbilicalis medialis [TA] , plica hypogastrica. median glossoepiglottic f. [TA] a f. of mucous membrane in the midline that extends from the back of the tongue to the epiglottis, forming the medial boundary of the epiglottic valleculae. SYN: plica glossoepiglottica mediana [TA] , frenulum epiglottidis, middle glossoepiglottic f.. median umbilical f. [TA] a f. of peritoneum on the anterior wall of the abdomen covering the urachus, or remains of the allantoic stalk. SYN: middle umbilical f., plica urachi, urachal f.. medullary folds SYN: neural folds. mesonephric f. SYN: mesonephric ridge. middle glossoepiglottic f. SYN: median glossoepiglottic f.. middle transverse rectal f. See transverse folds of rectum. middle umbilical f. SYN: median umbilical f.. mongolian f. SYN: palpebronasal f.. mucobuccal f. the line of flexure of the mucous membrane as it passes from the mandible or maxillae to the cheek. mucosal folds of gallbladder [TA] the interlacing folds of the mucosa that produce a honeycomb appearance in the interior of the gallbladder. SYN: plicae mucosae vesicae biliaris [TA] , rugae of gallbladder&star, rugae vesicae biliaris&star. nail f. SYN: nail wall. nasojugal f. a shallow groove in the skin that extends downward and laterally from the medial canthus. Nélaton f. See transverse folds of rectum. neural folds the elevated margins of the neural groove. SYN: medullary folds. opercular f. tissue forming a bridge or an adhesion between the tonsil and the anterior pillar of the fauces. palmate folds of cervical canal the two longitudinal ridges, anterior and posterior, in the mucous membrane lining the cervix uteri, from which numerous secondary folds, or rugae, branch off. SYN: plicae palmatae canalis cervicis uteri [TA] , arbor vitae uteri, lyra uterina. palpebronasal f. [TA] a f. of skin extending from the root of the nose to the medial termination of the eyebrow, overlapping the medial angle of the eye; its presence is normal in fetal life and in some Asians. SYN: plica palpebronasalis [TA] , medial canthic f.&star, epicanthal f., epicanthus, mongolian f.. paraduodenal f. [TA] a sickle-shaped f. of peritoneum sometimes found arching between the left side of the duodenojejunal flexure and the medial border of the left kidney; its right free edge contains the ascending branch of the left colic artery and inferior mesenteric vein; forms anterior boundary of the paraduodenal recess. SEE ALSO: paraduodenal recess. SYN: plica paraduodenalis [TA] , Treitz arch. pharyngoepiglottic f. SYN: lateral glossoepiglottic f.. pleuropericardial f. a tissue f. jutting into the right or left embryonic pericardioperitoneal canal; it separates the developing pericardium from the pleural cavity and is formed by the growth of the common cardinal veins to the midline of the body. SYN: pericardiopleural membrane, pleuropericardial membrane. pleuroperitoneal f. a tissue f. jutting into the caudal portion of the embryonic pericardioperitoneal canal; it develops into the dorsal portion of the definitive diaphragm and is formed by the lungs growing caudally and the liver expanding cranially. SYN: pleuroperitoneal membrane. posterior axillary f. bounds axilla posteriorly; formed by skin and fascia overlying latissimus dorsi and teres major muscles and tendons of insertion. presplenic f. a fan-shaped f. of peritoneum that passes from the gastrosplenic ligament near the lower end of the spleen to the phrenicocolic ligament with which it blends. It contains branches of the splenic or the left gastroepiploic artery. rectal folds SYN: transverse folds of rectum. rectouterine f. [TA] a f. of peritoneum, containing the rectouterine muscle, passing from the sacrum to the base of the broad ligament on either side, forming the lateral boundary of the rectouterine (Douglas) pouch. SYN: plica rectouterina [TA] , Douglas f., sacrouterine f.. rectovesical f. SYN: sacrovesical f.. retinal f. a congenital or secondary f., consequent to membrane contraction, producing star-shaped, meridional, or circular folds on the retina. retroauricular f. skin crease made by the junction of the pinna and the postauricular skin. retrotarsal f. SYN: conjunctival fornix. Rindfleisch folds semilunar folds of the serous surface of the pericardium, embracing the beginning of the aorta. sacrogenital folds peritoneal folds that extend backward from the sides of the bladder of the male or uterus of the female on either side of the rectum to the sacrum, forming the lateral boundaries of the rectovesical pouch. See sacrouterine f., sacrovesical f.. sacrouterine f. SYN: rectouterine f.. sacrovaginal f. the lower part of the sacrouterine f.. SYN: plica rectovaginalis. sacrovesical f. the f. of peritoneum in the male that bounds the rectovesical pouch laterally. SYN: rectovesical f.. salpingopalatine f. [TA] a ridge of mucous membrane passing from the anterior border of the opening of the auditory (eustachian) tube to the palate. SYN: plica salpingopalatina [TA] , plica tubopalatina. salpingopharyngeal f. [TA] a ridge of mucous membrane extending from the lower end of the tubal elevation along the wall of the pharynx overlying the salpingopharyngeus muscle. SYN: plica salpingopharyngea [TA] . Schultze f. SYN: amnionic f.. semilunar f. [TA] inconsistent curved f. connecting the palatoglossal arch and palatopharyngeal arch above the supratonsillar fossa; when present, it always contains lymphoid tissue. SYN: plica semilunaris [TA] . semilunar folds of colon [TA] one of the folds of the wall of the colon between sacculations. SYN: plicae semilunares coli [TA] , plicae semilunares of colon. semilunar conjunctival f. SYN: plica semilunaris of conjunctiva. spiral f. of cystic duct [TA] a series of crescentic folds of mucous membrane in the upper part of the cystic duct, arranged in a somewhat spiral manner. SYN: plica spiralis ductus cystici [TA] , Amussat valve, Heister valve, spiral valve of cystic duct, valvula spiralis. stapedial f. SYN: f. of stapes. f. of stapes [TA] a reflection of the delicate mucous membrane from the posterior wall of the tympanic cavity that covers the stapes. SYN: plica stapedialis, stapedial f.. sublingual f. [TA] an elevation in the floor of the mouth beneath the tongue, on either side, marking the site of the sublingual gland. SYN: plica sublingualis [TA] . superior duodenal f. [TA] a f. of peritoneum bounding the superior duodenal recess. SYN: plica duodenalis superior [TA] , duodenojejunal f.&star, plica duodenojejunalis&star. f. of superior laryngeal nerve [TA] the slight f. of mucosa in the piriform recess of the pharynx that encloses the superior laryngeal nerve. SYN: plica nervi laryngei superioris [TA] , f. of laryngeal nerve. synovial f. a ridge or projection of the synovial membrane of a joint extending toward or between the two articular surfaces. SYN: plica synovialis. tail f. the ventral folding of the caudal extremity of the embryonic disk. tarsal f. the f. marking the attachment of the levator palpebrae superioris muscle into the skin of the upper eyelid. transverse palatine f. [TA] a masticatory vestige on the hard palate; one of several irregular, sometimes branching, crests of soft tissue that radiate from the region of the incisive papillae at their most anterior parts and extend a slight distance backward, crossing the hard palate and reaching laterally for variable distances. SYN: plica palatina transversa [TA] , ruga palatina, transverse palatine ridge. transverse folds of rectum [TA] the three or four crescentic folds placed horizontally in the rectal mucous membrane; the superior rectal f. is situated near the beginning of the rectum on the left side; the middle rectal f. (Houston or Kohlrausch f.) is most prominent and consistent and projects from the right side about 8 cm above the anus (approximately the level of the floor of the rectouterine or rectovesical pouch); the inferior rectal f. is on the left side about 5 cm above the anus. SYN: plicae transversales recti [TA] , Houston folds, Kohlrausch folds, plicae recti, rectal folds, rectal valves. transverse vesical f. a duplication of peritoneum passing over the empty bladder, but obliterated when the viscus is full. SYN: plica vesicalis transversa. Treves f. SYN: ileocecal f.. triangular f. [TA] an inconstant f. of mucous membrane anterior to the palatine tonsil arising from the palatoglossal arch. SYN: plica triangularis [TA] . urachal f. SYN: median umbilical f.. ureteric f. SYN: interureteric crest. urorectal f. SYN: urorectal septum, urorectal membrane. folds of uterine tubes [TA] many longitudinal folds in the mucous membrane of the uterine (fallopian) tube. SYN: plicae tubariae tubae uterinae [TA] . uterovesical f. SYN: uterovesical ligament. vascular f. of the cecum [TA] a peritoneal f. that arches over a branch of the ileocolic artery and bounds in front a narrow recess, the superior ileocecal (or ileocolic) recess. SYN: plica cecalis vascularis [TA] . Vater f. a f. of mucous membrane in the duodenum just above the greater duodenal papilla. ventricular f. SYN: vestibular f.. vestibular f. [TA] one of the pair of folds of mucous membrane overlying the vestibular ligaments that stretch across the laryngeal cavity from the angle of the thyroid cartilage to the arytenoid cartilage; the right and left pair enclose a space called the rima vestibuli or false glottis, and form the superior boundary of the laryngeal ventricle. SYN: plica vestibularis [TA] , false vocal cord, plica ventricularis, ventricular band of larynx, ventricular f.. vestigial f. SYN: f. of left vena cava. vocal f. [TA] the sharp-edged f. of mucous membrane overlying the vocal ligament and stretching along either wall of the larynx from the angle between the laminae of the thyroid cartilage to the vocal process of the arytenoid cartilage; the vocal folds are the agents concerned in voice production. SYN: plica vocalis [TA] , chorda vocalis, Ferrein cords, labium vocale, true vocal cord, vocal cord, vocal shelf.

Frederic E.B., U.S. urologist, 1891–1966. See F. catheter, F. Y-plasty pyeloplasty.

folia (fo′le-a)
Plural of folium.

foliaceous (fo-le-a′shus)
SYN: foliate.

foliar (fo′le-ar)
SYN: foliate.

foliate (fo′le-at)
Pertaining to or resembling a leaf or leaflet. SYN: foliaceous, foliar, foliose.

folic acid (fo′lik)
1. A collective term for pteroylglutamic acids and their oligoglutamic acid conjugates. A collective term for pteroylglutamic acids and their oligoglutamic acid conjugates. N-[p-[[(2-Amino-4-hydroxypteridin-6- yl)methyl]amino]benzoyl]-L(+)-glutamic acid; specifically, pteroylmonoglutamic acid; the growth factor for Lactobacillus casei, and a member of the vitamin B complex necessary for the normal production of red blood cells; present, with or without L(+)- glutamic acid moieties, in peptide linkages in liver, green vegetables, and yeast; used to treat folate deficiency and megaloblastic anemia. SEE ALSO: homocysteine. 2. The growth factor for Lactobacillus casei, and a member of the vitamin B complex necessary for the normal production of red blood cells. It is a hemopoietic vitamin present, with or without l-(+)-glutamic acid moieties, in peptide linkages in liver, green vegetables, and yeast; used to treat folate deficiency and megaloblastic anemia, and to assist in lowering homocysteine levels. SYN: Lactobacillus casei factor, liver Lactobacillus casei factor, pteroylmonoglutamic acid. [L. folium, leaf, + -ic] Recent research has yielded a clearer understanding of the role of f. in human metabolism, identified health problems associated with dietary deficiency of f., provided evidence of therapeutic benefits of f. supplementation, and suggested that dietary allowances of folic acid formerly recommended (200 μg/day for men and 180 μg/day for women) are insufficient for certain persons, including pregnant women. Natural sources of f. include whole-grain breads and cereals, orange juice, lentils, beans, yeast, liver, and green leafy vegetables such as broccoli, kale, and spinach. F. and cobalamin (vitamin B12) serve as components of coenzymes in 1-carbon reactions such as the methylation of homocysteine to methionine. F. deficiency results in macrocytic anemia due to impairment of erythrocyte synthesis and is associated with elevation of plasma homocysteine levels, a risk factor for cardiovascular disease, including coronary atherosclerosis, stroke, and thromboembolism. Deficiency of f. in pregnancy is associated with an increased risk of neural tube defects such as spina bifida and anencephaly as well as an increased risk of preterm delivery and low birth weight. Persons with inherited deficiency of the enzyme 5,10 methylenetetrahydrofolic acid reductase have increased needs for dietary f.. The prevalence of the homozygous form of this deficiency may exceed 10% of the general population. Intake of f., pyridoxine (vitamin B6), and cobalamin above the current recommended dietary allowance has been associated with a substantially lower risk of coronary artery disease and of neural tube defects. Nutritionists recommend at least 400 μg/day of f. for all persons, and 1 mg/day or more for pregnant women and those with elevated plasma homocysteine levels. The Food and Drug Administration requires fortification of grains and cereals with f..

folie (fo-le′)
Old term for madness or insanity. [Fr. folly] f. à deux (a-du) identical or similar mental disorders, such as a paranoid fixation, usually affecting two members of the same family living together. SYN: shared psychotic disorder. [Fr. two] f. du doute (du-doot) an excessive doubting about all the affairs of life and a morbid scrupulousness concerning minutiae. [Fr. from doubt] f. du pourquoi (poor-kwah′) a psychopathologic tendency to ask questions. [Fr. why] f. gémellaire (zha-mel-ar′) a psychosis appearing simultaneously, or nearly so, in twins, who are not necessarily living together or intimately associated at the time. [Fr. relating to twins]

Otto K.O., U.S. biochemist, 1867–1934. See F. reaction, F. test, F.-Looney test.

folinate (fo′li-nat)
A salt or ester of folinic acid.

folinic acid (fo-lin′ik)
1. The active form of folic acid that acts as a formyl group carrier in transformylation reactions; the calcium salt, leucovorin calcium, has therapeutic use. 2. The term is occasionally applied to other folates. SYN: citrovorum factor, leucovorin.

foliose (fo′le-os)
SYN: foliate.

folium, pl .folia (fo′le-um, -le-a) [TA]
A broad, thin, leaflike structure. [L. a leaf] folia cerebelli [TA] SYN: folia of cerebellum. folia of cerebellum [TA] the narrow, leaf-like gyri of the cerebellar cortex. SEE ALSO: f. of vermis. SYN: folia cerebelli [TA] . folia linguae SYN: foliate papillae, under papilla. f. vermis [TA] SYN: f. of vermis. f. of vermis [TA] a small posterior subdivision of the superior vermis of the cerebellum consisting of lobule VIIA. SYN: f. vermis [TA] .

Folli, Folius
Cecilio (Caesilius), Venetian anatomist, 1615–1660. See F. process, follian process.

follicle (fol′i-kl) [TA]
1. A more or less spherical mass of cells usually containing a cavity. 2. A crypt or minute cul-de-sac or lacuna, such as the depression in the skin from which the hair emerges. SYN: folliculus [TA] . [L. folliculus, a small sac, dim. of follis, a pair of bellows] aggregated lymphatic follicles of small intestine SYN: aggregated lymphoid nodules of small intestine, under nodule. aggregated lymphatic follicles of vermiform appendix SYN: aggregated lymphoid nodules, under nodule. anovular ovarian f. a f. that does not contain an ovum. antral f. SYN: vesicular ovarian f.. atretic ovarian f. a f. that degenerates before coming to maturity; great numbers of such atretic follicles occur in the ovary before puberty; in the sexually mature woman, several are formed each month. SYN: corpus atreticum. dental f. the dental sac with its enclosed odontogenic organ and developing tooth. gastric follicles SYN: gastric glands, under gland. graafian f. SYN: vesicular ovarian f.. growing ovarian f. a f. having several layers of proliferating follicular cells surrounding the ovum, but separated from it by an extracellular glycoprotein layer (zona pellucida). hair f. [TA] a tubelike invagination of the epidermis from which the hair shaft develops and into which the sebaceous glands open; the f. is lined by a cellular inner and outer root sheath of epidermal origin and is invested with a fibrous sheath derived from the dermis. SYN: folliculus pili [TA] . intestinal follicles SYN: intestinal glands, under gland. Lieberkühn follicles SYN: intestinal glands, under gland. lingual follicles SYN: folliculi linguales, under folliculus. luteinized unruptured f. a f. that has undergone luteinization without prior rupture; once thought to cause infertility but now believed to occur equally often in fertile and infertile women. lymphatic follicles of larynx SYN: laryngeal lymphoid nodules, under nodule. lymphatic follicles of rectum SYN: folliculi lymphatici recti, under folliculus. mature ovarian f. a f. ready for ovulation; in the human ovary its antrum attains a diameter of 6–8 mm and presents a surface bulge; a first maturation (meiotic) division of the ovum usually occurs just prior to the rupture of the f.. Montgomery follicles SYN: areolar glands, under gland. multilaminar primary f. a primary ovarian f. with two or more layers of cuboidal follicular cells investing the oocyte. nabothian f. SYN: nabothian cyst. ovarian f. one of the spheroidal cell aggregations in the ovary containing an ovum. polyovular ovarian f. a f. containing more than one ovum. primary ovarian f. an ovarian f. before the appearance of an antrum; marked by developmental changes in the oocyte and follicular cells so that the latter form one or more layers of cuboidal or columnar cells; the f. becomes surrounded by a sheath of stroma, the theca. SYN: folliculus ovaricus primarius. primordial ovarian f. a f. in which the primordial oocyte is surrounded by a single layer of flattened follicular cells. sebaceous follicles SYN: sebaceous glands, under gland. secondary ovarian f. SYN: vesicular ovarian f.. solitary follicles SYN: solitary lymphatic nodules, under nodule. solitary lymphatic follicles SYN: solitary lymphatic nodules, under nodule. splenic lymph follicles small nodular masses of lymphoid tissue attached to the sides of the smaller arterial branches. SYN: folliculi lymphatici lienales, malpighian bodies, malpighian corpuscles (2) , malpighian glands, malpighian nodules, splenic corpuscles, splenic lymph nodules. follicles of thyroid gland SYN: folliculi glandulae thyroideae, under folliculus. unilaminar primary f. a primary ovarian f. with a single layer of cuboidal follicular cells investing the oocyte. vesicular f. SYN: vesicular ovarian f.. vesicular ovarian f. a f. in which the oocyte attains its full size and is surrounded by an extracellular glycoprotein layer (zona pellucida) that separates it from a peripheral layer of follicular cells permeated by one or more fluid-filled antra; the theca of the f. develops into internal and external layers. SYN: antral f., folliculus ovaricus vesiculosus, graafian f., secondary ovarian f., vesicular f..

follicular (fo-lik′u-lar)
Relating to a follicle or follicles.

folliculi (fo-lik′u-li)
Plural of folliculus.

folliculin (fo-lik′oo-lin)
SYN: estrone.

folliculin hydrate
SYN: estriol.

folliculitis (fo-lik-u-li′tis)
An inflammatory reaction in hair follicles; the lesions may be papules or pustules. f. abscedens et suffodiens a chronic progressive pustular f. in the scalp. f. barbae SYN: tinea barbae. f. decalvans a papular or pustular inflammation of the hair follicles of the scalp, of unknown cause, seen mostly in men, resulting in scarring and loss of hair in the affected area. eosinophilic pustular f. a dermatosis characterized by sterile pruritic papules and pustules that coalesce to form plaques with papulovesicular borders; spontaneous exacerbations and remissions may be accompanied by peripheral leukocytosis, eosinophilia, or both, and may result in eventual destruction of hair follicles and formation of eosinophilic abscesses. The disease has been reported in AIDS, and a possibly separate form of eosinophilic pustular f. occurs in infants. SYN: Ofuji disease. f. keloidalis SYN: acne keloid. f. nares perforans inflammation of a hair follicle in the nose; the infection extends to, and perforates, the cutaneous surface. perforating f. erythematous papules with a central keratin plug that are scattered on the arms, thighs, and buttocks; dermal fibers are seen in biopsies extending into the follicle; similar changes are seen especially in diabetics on hemodialysis. SEE ALSO: hyperkeratosis follicularis et parafollicularis. f. ulerythematosa reticulata erythematous “ice-pick” or pitted scars on the cheeks; a scarring type of f., associated with keratosis pilaris and commonly inherited as an autosomal dominant trait.

folliculoma (fo-lik-u-lo′ma)
1. SYN: granulosa cell tumor. 2. Cystic enlargement of a graafian follicle.

folliculosis (fo-lik-u-lo′sis)
Presence of lymph follicles in abnormally great numbers.

folliculus, pl .folliculi (fo-lik′u-lus, -u-li) [TA]
SYN: follicle. [L. a small sac, dim. of follis, bellows] folliculi glandulae thyroideae the small spherical vesicular components of the thyroid gland lined with epithelium and containing colloid in varying amounts; the colloid serves for storage of the thyroid hormone precursor, thyroglobulin. SYN: follicles of thyroid gland. folliculi linguales collections of lymphoid tissue in the mucosa of the pharyngeal part of the tongue posterior to the terminal sulcus collectively forming the lingual tonsil. SYN: lenticular papillae, lingual follicles. folliculi lymphatici aggregati SYN: aggregated lymphoid nodules of small intestine, under nodule. folliculi lymphatici aggregati appendicis vermiformis SYN: aggregated lymphoid nodules, under nodule. folliculi lymphatici gastrici SYN: gastric lymphoid nodules, under nodule. folliculi lymphatici laryngei SYN: laryngeal lymphoid nodules, under nodule. folliculi lymphatici lienales SYN: splenic lymph follicles, under follicle. folliculi lymphatici recti scattered collections of lymphoid tissue in the wall of the rectum. SYN: lymphatic follicles of rectum. folliculi lymphatici solitarii SYN: solitary lymphatic nodules, under nodule. f. lymphaticus SYN: lymphoid nodule. f. ovaricus primarius SYN: primary ovarian follicle. f. ovaricus vesiculosus SYN: vesicular ovarian follicle. f. pili [TA] SYN: hair follicle.

Ivar A., Norwegian physician, 1888–1973. See F. disease.

follistatin (fol-i-stat-′n)
A peptide synthesized by granulosa cells in response to FSH that suppresses FSH activity, probably by binding activins. [follicle + -stat + -in]

follitropin (fol-i-tro′pin)
An acidic glycoprotein hormone of the anterior pituitary that stimulates the graafian follicles of the ovary and assists subsequently in follicular maturation and the secretion of estradiol; in the male, it stimulates the epithelium of the seminiferous tubules and is partially responsible for inducing spermatogenesis. SYN: follicle-stimulating hormone, follicle-stimulating principle, gametokinetic hormone. [follicle + G. trope, a turning, + -in]

Jean C.E., French anatomist and ophthalmologist, 1822–1876. See F. valvule.

fomentation (fo-men-ta′shun)
1. A warm application. SEE ALSO: poultice, stupe. 2. Application of warmth and moisture in the treatment of disease. [L. fomento, pp. -atus, to foment, fr. fomentum, a poultice, fr. foveo, to keep warm]

fomes, pl .fomites (fo′mez, fom′i-tez)
Objects, such as clothing, towels, and utensils that possibly harbor a disease agent and are capable of transmitting it; usually used in the plural. SYN: fomite. [L. tinder, fr. foveo, to keep warm]

fomite (fo′mit)
SYN: fomes. [L. fomitis, gen. of fomes. See fomes.]

fomites (fo′mi-tez)
Plural of fomes.

fonazine mesylate (fo′na-zen)
A serotonin inhibitor with muscle relaxant properties. SYN: dimethothiazine mesylate.

Anton, Swiss physician, 1881–1968. See F. solution.

Fonsecaea (fon-se-se′a)
A genus of fungi of which at least two species, F. pedrosoi and F. compacta, cause chromoblastomycosis.

Francois M., French thoracic surgeon, *1929. See F. procedure, F. operation.

Felice, Italian physiologist, 1730–1805. See F. canal, F. spaces, under space.

Arturo, Italian dermatologist, 1873–1950. See F. stain, F.-Masson silver stain, Masson-F. ammoniac silver stain.

fontanelle (fon′ta-nel′) [NA]
One of several membranous intervals at the margins of the cranial bones in the infant. See cranial fontanelles. SYN: fonticulus. [Fr. dim. of fontaine, fountain, spring] anterior f. [NA] a diamond-shaped membranous interval at the junction of the coronal, sagittal, and metopic sutures where the frontal angles of the parietal bones meet the two ununited halves of the frontal bone. SYN: bregmatic f., fonticulus anterior, frontal f.. anterolateral f. SYN: sphenoidal f.. bregmatic f. SYN: anterior f.. Casser f. SYN: mastoid f.. cranial fontanelles [NA] the membranous intervals between the angles of the cranial bones in the infant; they include the midline anterior fontanel and posterior fontanel, and the paired sphenoidal fontanel and mastoid fontanel. SYN: fonticuli cranii. frontal f. SYN: anterior f.. Gerdy f. SYN: sagittal f.. mastoid f. [NA] the membranous interval on either side between the mastoid angle of the parietal bone, the petrous portion of the temporal bone, and the occipital bone. SYN: fonticulus mastoideus [NA] , fonticulus posterolateralis&star, Casser f., posterolateral f.. occipital f. SYN: posterior f.. posterior f. a triangular interval at the union of the lambdoid and sagittal sutures where the occipital angles of the parietal bones meet the occipital. SYN: fonticulus posterior, occipital f.. posterolateral f. SYN: mastoid f.. sagittal f. [NA] an occasional fontanel-like defect in the sagittal suture in the newborn. SYN: Gerdy f.. sphenoidal f. [NA] an irregularly shaped interval on either side where the frontal, sphenoidal angle of the parietal, squamous portion of the temporal and greater wing of the sphenoid meet. SYN: fonticulus sphenoidalis [NA] , fonticulus anterolateralis&star, anterolateral f..


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