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Medical Dictionary


limen, pl .limina (li′men, lim′i-na) [TA]
1. Entrance; the external opening of a canal or space, such as l. insulae [TA]. 2. SYN: threshold. [L.] difference l. a barely noticeable change in the intensity or frequency of a stimulus. l. insulae [TA] the band of transition between the anterior portion of the gray matter of the insula and the anterior perforated substance; it is formed by a narrow strip of olfactory cortex along the lateral side of the lateral olfactory stria. SYN: threshold of island of Reil. l. nasi [TA] a ridge marking the boundary between the nasal cavity proper and the vestibule. SYN: threshold of nose.

limerence (lim′er-ens)
Emotional excitement of being in love.

limes (L) (li′mez)
A boundary, limit, or threshold. SEE ALSO: L doses, under dose. [L.]

liminal (lim′i-nal)
1. Pertaining to a threshold. 2. Pertaining to a stimulus just strong enough to excite a tissue, e.g., nerve or muscle. [L. limen (limin-), a threshold]

liminometer (lim-i-nom′e-ter)
An instrument for measuring the strength of a stimulus which is barely sufficient to produce a reflex response. [L. limen, threshold, + G. metron, measure]

A boundary or end. [L. limes, boundary] critical l. the upper or lower boundary of a laboratory test result that indicates a life-threatening value. elastic l. the greatest stress to which a material may be subjected and still be capable of returning to its original dimensions when the forces are released. Hayflick l. the l. of human cell division in subcultures; such cells typically divide only about 50 times before dying out. permissible exposure l. an occupational health standard to safeguard workers against dangerous contaminants in the workplace. proportional l. the greatest stress that a material is capable of sustaining without any deviation from proportionality of stress to strain (Hooke law). quantum l. the shortest wavelength found in an x-ray spectrum. short-term exposure l. (STEL) the maximum concentration of a chemical to which workers may be exposed continuously for up to 15 minutes without danger to health or work efficiency and safety. tolerance limits specified performance limits for allowable error for a test; the limits selected should depend on both the effect of the error on the clinical significance of a test and on what is technically achievable.

Limnatis nilotica (lim-na′tis ni-lot′i-ka)
The horse leech; a species of land-leech of southern Europe and northern Africa which may infest the nostrils or gullet and, attaching itself to the mucous membrane, may cause hemorrhages and anemia in horses and other animals drinking leech-infested water. [G. limne, pool]

limnemia (lim-ne′me-a)
SYN: chronic malaria. [G. limne, marsh, + haima, blood]

limnemic (lim-ne′mik)
Suffering from chronic malaria.

limnology (lim-nol′o-je)
Study of the physical, chemical, meteorologic, and biologic conditions in fresh water; a branch of ecology. [G. limne, pool, + logos, study]

limon, gen. limonis (li′mon, li-mo′nis)
SYN: lemon. [L.]

limophthisis (li-mof′thi-sis)
Rarely used term for emaciation from lack of sufficient nourishment. [G. limos, hunger, + phthisis, wasting]

A lame walk with a yielding step; asymmetrical gait. SEE ALSO: claudication.

Acronym of linear accelerator.

lincomycin (lin-ko-mi′sin)
An antibacterial substance, composed of substituted pyrrolidine and octapyranose moities, produced by Streptomyces lincolnensis; active against Gram-positive organisms; used medicinally as l. hydrochloride.

lincture, linctus (link′choor, link′tus)
An electuary or a confection; originally a medicinal preparation taken by licking. [L. lingo, pp. linctus, to lick]

lindane (lin′dan)
Used as a scabicide, pediculicide, and insecticide (10 times more toxic for houseflies than DDT).

Arvid, Swedish pathologist, 1892–1958. See L. disease, L. tumor, von Hippel-L. syndrome.

Charles A., U.S. aviator, 1902–1974. See Carrel-L. pump.

Karl D., Austrian ophthalmologist, 1883–1961. See L. bodies, under body.

Johan Torsten, Swedish physician, *1906. See Fahraeus-L. effect.

line (lin) [TA]
1. A mark, strip, or streak. In anatomy, a long, narrow mark, strip, or streak distinguished from the adjacent tissues by color, texture, or elevation. SEE ALSO: linea. 2. A unit of measurement used by histologists in the 19th century; it varied in different countries from 110–112 of an English inch. 3. A laboratory derivative of a stock of organisms maintained under defined physical conditions. 4. A section of tubing supplying fluid or conducting impulses for monitoring equipment; e.g., intravenous l., arterial l.. SYN: linea [TA] . [L. linea, a linen thread, a string, l., fr. linum, flax] absorption lines the dark lines in the solar spectrum due to absorption by the solar and the earth's atmosphere; the phenomenon occurs because rays passing from an incandescent body through a colder medium are absorbed by elements in that medium. accretion lines lines seen in microscopic sections of the enamel, marking successive layers of added material. alveolonasal l. a l. connecting the alveolar point and the nasion. Amberg lateral sinus l. a l. dividing the angle formed by the anterior edge of the mastoid process and the temporal l.. anocutaneous l. [TA] inferior border of the anal pecten where the stratified squamous epithelium changes from the hairless anoderm to typical (hairy) skin; commonly coincides with the inferior border of the internal anal sphincter. SYN: linea anorectalis [TA] . anterior axillary l. [TA] a vertical l. extending inferiorly from the anterior axillary fold. SYN: linea axillaris anterior [TA] , linea preaxillaris, preaxillary l.. anterior junction l. radiographic projection of the mediastinal tissue septum between the upper lobes behind the sternum. anterior median l. [TA] the l. of intersection of the midsagittal plane with the anterior surface of the body. SYN: linea mediana anterior [TA] . arcuate l. [TA] an arching or bow-shaped l.. See arcuate l. of ilium, arcuate l. of rectus sheath. SYN: linea arcuata [TA] . arcuate l. of ilium [TA] the iliac portion of the linea terminalis of the bony pelvis. SYN: linea arcuata ossis ilii [TA] . arcuate l. of rectus sheath [TA] a crescentic l., not always clearly defined, which marks the lower limit of the posterior layer of the sheath of the rectus abdominis muscle. SYN: linea arcuata vaginae musculi recti abdominis [TA] , Douglas l., linea semicircularis, semicircular l.. arterial l. an intraarterial catheter. axillary l. anterior axillary l., midaxillary l., posterior axillary l.. Baillarger lines two laminae of white fibers that course parallel to the surface of the cerebral cortex and are visible as the stria of the internal pyramidal layer [TA] in cortical layer V (outer l.) and the stria of the internal granular layer [TA] in cortical layer IV (inner l.) that appear in myelin stained sections cut perpendicular to the surface; the l. of Gennari in the calcarine cortex represents the outer of these lines. SYN: stria laminae granularis internae [TA] , stria laminae pyramidalis internae [TA] , Baillarger bands. base l. See orbitomeatal plane (1) . basinasal l. a l. connecting the basion and the nasion. SYN: nasobasilar l.. Beau lines transverse grooves on the fingernails following severe febrile disease, malnutrition, trauma, myocardial infarction, etc. l. of Bechterew SYN: band of Kaes-Bechterew. bismuth l. a black zone on the free marginal gingiva, often the first sign of poisoning from prolonged parenteral administration of bismuth. black l. SYN: linea nigra. lines of Blaschko a pattern of distribution of skin lesions or pigmentary anomalies; linear on the extremities, S-shaped curves on the abdomen, and V-shaped on the back, thought to result from genetic mosaicism (q.v.) and the interplay of transverse clonal proliferation and longitudinal growth and flexion of the embryo. blue l. a bluish l. along the free border of the gingiva, occurring in chronic heavy metal poisoning. Brödel bloodless l. l. running somewhat posterior to the lateral convex border of the kidney between anterior and posterior renal segments demarcating the areas of distribution of the anterior and posterior branches of the renal artery; it is in fact only relatively avascular. Burton l. a bluish l. on the free border of the gingiva, occurring in lead poisoning. calcification lines of Retzius incremental lines of rhythmic deposition of successive layers of enamel matrix during development. SYN: lines of Retzius. Camper l. the l. running from the inferior border of the ala of the nose to the superior border of the tragus of the ear. cell l. 1. in tissue culture, the cells growing in the first or later subculture from a primary culture. SEE ALSO: established cell l.. 2. a clone of cultured cells derived from an identified parental cell type. cement l. the refractile boundary of an osteon or interstitial lamellar system in compact bone. cervical l. a continuous anatomical irregular curved l. marking the cervical end of the crown of a tooth and the cementoenamel junction. Chamberlain l. a l. drawn from the posterior margin of the hard palate to the dorsum of the foramen magnum; in basilar impression, the odontoid process rises above this l.. Chaussier l. the anteroposterior l. of the corpus callosum as appearing on median section of the brain. choroid l. [TA] SYN: tenia choroidea. Clapton l. a greenish discoloration of the marginal gingiva in cases of chronic copper poisoning. cleavage lines SYN: tension lines. Conradi l. a l. extending from the base of the ensiform cartilage to the apex beat of the heart, corresponding approximately to the lower edge of the cardiac area. contour lines of Owen SYN: Owen lines. Correra l. SYN: pleural lines. costal l. of pleural reflection surface projection of the sharp l. along which the costal part of the parietal pleura becomes continuous with the diaphragmatic part inferiorly; this l. intersects midclavicular l. at the level of the 8th rib, the midaxillary l. at the level of the 10th rib, and the paravertebral l. at the level of the 12th rib; thoracentesis is performed one rib level higher in these lines. costoclavicular l. SYN: parasternal l.. costophrenic septal lines SYN: Kerley B lines. Crampton l. a l. from the apex of the cartilage of the last rib downward and forward nearly to the crest of the ilium, then forward parallel with it to a little below the anterior superior spine; a guide to the common iliac artery. Daubenton l. the l. passing between the opisthion and the basion. SEE ALSO: Daubenton angle, Daubenton plane. l. of demarcation a zone of inflammatory reaction separating a gangrenous area from healthy tissue. demarcation l. of retina junction of avascular and vascular retina in retinopathy of prematurity; l. marking the limits of an old retinal detachment. Dennie l. SYN: Dennie-Morgan fold. dentate l. SYN: pectinate l.. developmental lines SYN: developmental grooves, under groove. Douglas l. SYN: arcuate l. of rectus sheath. Eberth lines lines appearing between the cells of the myocardium when stained with silver nitrate. Egger l. seldom-used term for the circular l. of adhesion between the vitreous and posterior lens. Ehrlich-Türk l. seldom-used term for the vertical, thin deposition of material on the posterior surface of the cornea in uveitis. epiphysial l. [TA] the l. of junction of the epiphysis and diaphysis of a long bone where growth in length occurs. SYN: linea epiphysialis [TA] , synchondrosis epiphyseos. established cell l. cells that demonstrate the potential for indefinite subculture in vitro. Farre l. a whitish l. marking the insertion of the mesovarium at the hilum of the ovary. Feiss l. a l. running from the medial malleolus to the plantar aspect of the first metatarsophalangeal joint. Ferry l. an iron l. occurring in the corneal epithelium anterior to a filtering bleb. l. of fixation a l. joining the object (or point of fixation) with the fovea. Fleischner lines coarse linear shadows on a chest radiograph, indicating bands of subsegmental atelectasis. Fraunhofer lines a number of the most prominent of the absorption lines of the solar spectrum. fulcrum l. an imaginary l. around which a removable partial denture tends to rotate. SYN: rotational axis. l. of Gennari a prominent white l. appearing in perpendicular sections of the visual cortex (Brodmann area 17) at about mid-thickness of the cortical gray matter, corresponding to the particularly well-developed outer l. of Baillarger of that cortical area, and composed largely of tangentially disposed intracortical association fibers. SYN: occipital stripe [TA] , stria occipitalis [TA] , occipital l.&star, Gennari band, Gennari stria, stripe of Gennari. germ l. a collection of haploid cells derived from the specialized cells of the primitive gonad. gluteal lines [TA] one of three rough curved lines on the outer surface of the ala of the ilium: anterior gluteal l., inferior gluteal l., and posterior gluteal l.; the two areas bounded by these give attachment to the gluteus minimus muscle below and gluteus medius above. SYN: lineae gluteae [TA] . Granger l. on lateral skull radiographs, the l. produced by the groove of the optic chiasm or sulcus prechiasmaticus. growth arrest lines dense lines parallel to the growth plates of long bones on radiographs, representing temporary slowing or cessation of longitudinal growth. SYN: Harris lines. Gubler l. the level of the superficial origin of the trigeminus on the pons, a lesion below which causes Gubler paralysis. gum l. the position of the margin of the gingiva in relation to the teeth in the dental arch. Haller l. SYN: linea splendens. Hampton l. a thin radiolucent band across the neck of a contrast-filled benign gastric ulcer, indicating mucosal edema. Cf.:Carman sign. Harris lines SYN: growth arrest lines. Head lines bands of cutaneous hyperesthesia associated with acute or chronic inflammation of the viscera. SYN: Head zones, tender lines, tender zones. Hensen l. SYN: H band. highest nuchal l. [TA] a l. above and parallel to the superior nuchal l. on the external surface of the occipital bone; it gives attachment to the epicranial aponeurosis and occipitalis muscle. SYN: linea nuchae suprema [TA] . high lip l. the greatest height to which the lip is raised in normal function or during the act of smiling broadly. Hilton white l. SYN: white l. of anal canal. His l. a l. extending from the tip of the anterior nasal spine (acanthion) to the hindmost point on the posterior margin of the foramen magnum (opisthion), dividing the face into an upper and a lower, or dental part. Holden l. the crease or furrow of the skin of the groin caused by flexion of the thigh. Hudson-Stähli l. a brown, horizontal l. across the lower third of the cornea, occasionally seen in the aged and also in association with corneal opacities. Hunter l. SYN: linea alba. Hunter-Schreger lines SYN: Hunter-Schreger bands, under band. iliopectineal l. SYN: linea terminalis of pelvis. imbrication lines of von Ebner incremental lines in the dentin of the tooth that reflect variations in mineralization during dentin formation; the distance between the lines corresponds to the daily rate of dentin formation. SYN: incremental lines of von Ebner. incremental lines 1. in the enamel, calcification lines of Retzius; 2. in the dentin, imbrication or incremental lines of von Ebner, and Owen lines. incremental lines of von Ebner SYN: imbrication lines of von Ebner. inferior nuchal l. [TA] a ridge that extends laterally from the external occipital crest toward the jugular process of the occipital bone. SYN: linea nuchae inferior [TA] . inferior temporal l. of parietal bone [TA] the lower of two curved lines on the parietal bone; it marks the outer limit of attachment of the temporalis muscle. SYN: linea temporalis inferior ossis parietalis [TA] , temporal ridge. infracostal l. SYN: subcostal plane. intercondylar l. of femur [TA] a faint transverse ridge separating the floor of the intercondylar fossa from the popliteal surface of the femur; it affords attachment to the posterior portion of the articular capsule of the knee. SYN: linea intercondylaris femoris [TA] . intermediate l. of iliac crest SYN: intermediate zone of iliac crest. interspinal l. l. passing through both anterior superior iliac spines indicating the interspinal plane. SYN: linea interspinalis. intertrochanteric l. [TA] a rough l. that separates the neck and shaft of the femur anteriorly; it passes downward and medially from the greater trochanter to the lesser trochanter and continues into the medial lip of the linea aspera. SYN: linea intertrochanterica [TA] , linea spiralis, spiral l.. intertubercular l. horizontal l. passing through tubercles of both iliac crests, indicating the intertubercular plane. SYN: linea intertubercularis. iron l. deposition of iron in the corneal epithelium. isoelectric l. the baseline of the electrocardiogram, recorded in the TP interval during rhythms with P waves. l. of Kaes SYN: band of Kaes-Bechterew. Kerley A lines images of deep interlobular septa; longer, thicker, and more central than Kerley B lines; usually in upper lobes. Kerley B lines fine peripheral septal lines. SYN: costophrenic septal lines. Kerley C lines a nonspecific fine reticular pattern on chest radiographs. Kilian l. a transverse l. marking the promontory of the pelvis. Langer lines SYN: tension lines. Lanz l. SYN: interspinous plane. lead l. deposits of lead sulfide in the gingiva in areas of chronic inflammation. Looser lines radiolucent bands in the cortex of a bone; usually indicates osteomalacia. SYN: Looser zones. low lip l. 1. the lowest position of the lower lip during the act of smiling or voluntary retraction; 2. the lowest position of the upper lip at rest. M l. a fine l. in the center of the A band of the sarcomere of striated muscle myofibrils. SYN: M band, mesophragma. Mach l. the apparent l. of contrasting density bordering a soft tissue shadow on a radiograph; it is an optical illusion constructed by the observer's retina. mammary l. a transverse l. drawn between the two nipples. mammillary l. [TA] a vertical l. passing through the nipple on either side. SYN: linea mammillaris [TA] , nipple l.. McKee l. a l. drawn from the tip of the cartilage of the eleventh rib to a point 3.5 cm medial to the anterior superior spine, then curved downward, forward, and inward to just above the deep inguinal ring; a guide to the common iliac artery. median l. anterior median l., posterior median l.. Mees lines horizontal white bands of the nails seen in chronic arsenical poisoning, and occasionally in leprosy. SYN: Mees stripes. mercurial l. a bluish brown pigmentation seen at the gingival margin and associated with mercury poisoning (mercurial stomatitis). Meyer l. a l. through the axis of the big toe and passing the midpoint of the heel in a normal foot. midaxillary l. [TA] a vertical l. intersecting a point midway between the anterior and posterior axillary folds or lines. SYN: linea axillaris media [TA] , linea medio-axillaris, middle axillary l.. midclavicular l. [TA] a vertical l. passing through the midpoint of the clavicle. SYN: linea medioclavicularis [TA] . middle axillary l. SYN: midaxillary l.. milk l. SYN: mammary ridge. Monro l. SYN: Monro-Richter l.. Monro-Richter l. a l. passing from the umbilicus to the anterior superior iliac spine. McBurney point occurs on this l.. SYN: Monro l., Richter-Monro l.. Muehrcke lines white lines, parallel with the lunula and separated from each other by normal pink areas; associated with hypoalbuminemia; the lines do not move outward with nail growth, but disappear when the serum albumin returns to normal. mylohyoid l. [TA] a ridge on the inner surface of the mandible running from a point inferior to the mental spine upward and backward to the ramus behind the last molar tooth; it gives attachment to the mylohyoid muscle and the lowermost part of the superior constrictor of the pharynx. SYN: linea mylohyoidea [TA] , mylohyoid ridge. nasobasilar l. SYN: basinasal l.. Nélaton l. a l. drawn from the anterior superior iliac spine to the tuberosity of the ischium; normally the greater trochanter lies in this l., but in cases of iliac dislocation of the hip or fracture of the neck of the femur the trochanter is felt above the l.. SYN: Roser-Nélaton l.. neonatal l. in deciduous teeth, a l. of demarcation between prenatal and postnatal enamel. SYN: neonatal ring. nipple l. SYN: mammillary l.. Obersteiner-Redlich l. SYN: Obersteiner-Redlich zone. oblique l. [TA] a diagonal, sloping or slanting l.; a l. which is neither parallel nor perpendicular, neither horizontal nor vertical. See oblique l. of mandible, oblique l. of thyroid cartilage. SYN: linea obliqua [TA] . oblique l. of mandible [TA] the l. on the external surface of the mandible that extends from the mental tubercle to the ramus and separates the alveolar and basilar parts of the bone. SYN: linea obliqua mandibulae [TA] , external oblique ridge. oblique l. of thyroid cartilage [TA] a ridge on the outer surface of the thyroid cartilage that gives attachment to the sternothyroid and thyrohyoid muscles. SYN: linea obliqua cartilaginis thyroideae [TA] . occipital l. l. of Gennari. l. of occlusion the alignment of the occluding surfaces of the teeth in the horizontal plane. SEE ALSO: occlusal plane. Ogston l. a l. drawn from the adductor tubercle of the femur to the intercondylar notch; a guide to resection of the medial condyle for knock-knee. Ohngren l. a theoretical plane passing between the medial canthus of the eye and the angle of the mandible; used as an arbitrary dividing l. in classifying localized tumors of the maxillary sinus; tumors above the l. invade vital structures early and have a poorer prognosis, whereas those below the l. have a more favorable prognosis. orbitomeatal l. See orbitomeatal plane. Owen lines accentuated incremental lines in the dentin thought to be due to disturbances in the mineralization process. SYN: contour lines of Owen. paraspinal l. radiographic image of the interface between the lung and paravertebral soft tissues. parasternal l. [TA] a vertical l. equidistant from the sternal and midclavicular lines. SYN: linea parasternalis [TA] , costoclavicular l.. paravertebral l. [TA] a vertical l. corresponding to the tips of the transverse processes of the vertebrae. SYN: linea paravertebralis [TA] . Paris l. a unit of microscopic measurement as used in Kölliker's Mikroskopische Anatomie; it was equal to 0.0888138 of an inch. Paton lines SYN: striae retinae, under stria. pectinate l. [TA] the l. between the simple columnar epithelium of the rectum and the stratified epithelium of the anal canal, usually defined as being at the level of the anal valves at the bases of the anal columns. SYN: linea pectinata canalis analis [TA] , dentate l.. pectineal l. of femur [TA] a ridge running down the posterior surface of the shaft of the femur from the lesser trochanter to which the pectineus muscle attaches; continuous superiorly with intertrochanteric l. and inferiorly with the medial lip of the linea aspera. SYN: linea pectinea femoris [TA] . pectineal l. of pubis SYN: pecten pubis. PICC l. acronym for peripherally inserted central catheter; a long-term central venous catheter, inserted peripherally. pleural lines on a chest radiograph, the shadow of the soft tissues between the aerated lung and the bones of the thorax. SYN: Correra l., pleural stripe. lines of pleural reflection lines, usually projected onto the surface of the thoracic wall, indicating the abrupt change in direction of the parietal pleura as it passes from one wall of the pulmonary cavity to another. SEE ALSO: vertebral l. of pleural reflection. pleuroesophageal l. on a frontal chest radiograph, the image of the interface between the right lung and esophagus, the boundary of the azygoesophageal recess. Poirier l. a l. extending from the nasion to the lambda. popliteal l. SYN: soleal l.. postaxillary l. SYN: posterior axillary l.. posterior axillary l. [TA] a vertical l. extending inferiorly from the posterior axillary fold. SYN: linea axillaris posterior [TA] , linea postaxillaris, postaxillary l.. posterior junction l. radiographic image of the mediastinal septum between the upper lobes behind the esophagus, above the aortic arch. posterior median l. [TA] the l. of intersection of the midsagittal plane with the posterior surface of the body. SYN: linea mediana posterior [TA] . Poupart l. a vertical l. passing through the center of the inguinal ligament on either side; it marks off the hypochondriac, lumbar, and iliac from the epigastric, umbilical, and hypogastric regions, respectively. preaxillary l. SYN: anterior axillary l.. Reid base l. a l. drawn from the inferior margin of the orbit to the auricular point (center of the orifice of the external acoustic meatus) and extending backward to the center of the occipital bone. Used as the zero plane in computed tomography. retentive fulcrum l. 1. an imaginary l. connecting the retentive points of clasp arms on retaining teeth adjacent to mucosa-borne denture bases; 2. an imaginary l. connecting the retentive points of clasp arms, around which l. the denture tends to rotate when subjected to forces such as the pull of sticky foods. lines of Retzius SYN: calcification lines of Retzius. Richter-Monro l. SYN: Monro-Richter l.. Roser-Nélaton l. SYN: Nélaton l.. rough l. SYN: linea aspera. sagittal l. any l. parallel to the midline, indicating (occurring within) a sagittal plane. Salter incremental lines transverse lines sometimes seen in dentin, due to improper calcification. S-BP l. a l. connecting the sella with the Bolton point; it indicates the posterior portion of the cranial base in cephalometrics. scapular l. [TA] a vertical l. passing through the inferior angle of the scapula. SYN: linea scapularis [TA] . Schreger lines SYN: Hunter-Schreger bands, under band. semicircular l. SYN: arcuate l. of rectus sheath. semicircular l. of Douglas a crescent-shaped l. that defines the end of the posterior fascial sheath of the rectus abdominis muscle. semilunar l. SYN: linea semilunaris. septal lines radiographic images of thickened interlobular septa, most often along the lateral border of lung, extending to pleura; Kerley A and B lines; usually caused by septal edema and fibrosis, also carcinomatosis. Sergent white l. SYN: white l. (2) . Shenton l. a curved l. formed by the top of the obturator foramen and the inner side of the neck of the femur, seen on an anteroposterior frontal radiograph of a normal hip joint; it is disturbed in lesions of the joint such as dislocation or fracture. S-N l. a l. connecting a point (S) representing the center of the sella turcica with the frontonasal junction (N); it denotes the anterior portion of the cranial base in cephalometrics. soleal l. [TA] a ridge that extends obliquely downward and medially across the back of the tibia from the fibular articular facet; it gives origin to the soleus muscle. SYN: linea musculi solei [TA] , l. for soleus muscle, linea poplitea, popliteal l.. l. for soleus muscle SYN: soleal l.. Spigelius l. SYN: linea semilunaris. spiral l. SYN: intertrochanteric l.. stabilizing fulcrum l. an imaginary l. connecting occlusal rests, around which l. the denture tends to rotate under masticatory force. sternal l. [TA] a vertical l. corresponding to the lateral margin of the sternum. SYN: linea sternalis [TA] . sternal l. of pleural reflection surface projection of the sharp l. along which the costal part of the parietal pleura becomes continuous with the mediastinal part anteriorly; the right and left sternal lines of pleural reflection are parallel to the median plane, posterior to the sternum, at the level of costal cartilages 2–4; at the level of the costal cartilage 4, the left l. turns laterally to parallel the left margin of the sternum, creating a “notch” that is shallower than the cardiac notch of the left lung and an area where the pericardial sac contacts the anterior thoracic wall without intervening pleura sac—significant for pericardiocentesis. Stocker l. a fine l. of pigment in the corneal epithelium near the head of a pterygium. subcostal l. a transverse l. transecting the inferiormost border of the thoracic cage, indicating the subcostal plane. SEE ALSO: subcostal plane. SYN: linea subcostalis. superior nuchal l. [TA] the ridge that extends laterally from the external occipital protuberance toward the lateral angle of the occipital bone; it gives attachment to the trapezius, sternocleidomastoid, and splenius capitis muscles. SYN: linea nuchae superior [TA] . superior temporal l. of parietal bone [TA] the upper of two curved lines on the parietal bone; the temporal fascia is attached to it. SYN: linea temporalis superior ossis parietalis [TA] , temporal ridge. supracrestal l. a transverse l. transecting the high point of both iliac crests, indicating the supracristal plane. SEE ALSO: supracristal plane. SYN: linea supracristalis. survey l. 1. a l. scribed on an abutment tooth of a dental cast by means of a dental surveyor indicating the height of contour of the tooth according to a specific path of insertion; 2. a l. which serves as a guide in the proper location of various parts of a clasp assembly for a removable partial denture. SYN: clasp guideline, Cummer guideline. Sydney l. SYN: Sydney crease. sylvian l. the l. of the posterior limb of the lateral sulcus (sylvian fissure) of the cerebral cortex. temporal l. inferior temporal l. of parietal bone, superior temporal l. of parietal bone. temporal l. of frontal bone [TA] anterior continuation of the inferior temporal l. of the temporal bone onto the lateral aspect of the external surface of the frontal bone, demarcating the temporal surface of the bone. SYN: linea temporalis ossis frontalis [TA] . tender lines SYN: Head lines. tension lines [TA] lines that can be extrapolated by connecting linear openings made when a round pin is driven into the skin of a cadaver, resulting from the principal axis of orientation of the subcutaneous connective tissue (collagen) fibers of the dermis; they vary in direction with the region of the body surface. SYN: lineae distractionis [TA] , cleavage lines, Langer lines. terminal l. SYN: linea terminalis of pelvis. Topinard l. a l. running between the glabella and the mental point. tram lines the images of bronchial walls on a plain chest radiograph. When seen distally, indicative of bronchiectasis or chronic bronchitis; usually thickened; colloq., British. SYN: radiographic parallel l. shadow. trapezoid l. [TA] the area on the inferior surface of the clavicle near its lateral extremity on which the trapezoid ligament attaches. SYN: linea trapezoidea [TA] , trapezoid ridge. Ullmann l. the l. of displacement in spondylolisthesis. vertebral l. of pleural reflection approximation of the more gradual reflection of the costal part of the parietal pleura onto the mediastinum posteriorly. Vesling l. SYN: raphe of scrotum. vibrating l. the imaginary l. across the posterior part of the palate, marking the division between the movable and immovable tissues. l. of vision SYN: visual axis. Wegner l. a narrow, whitish, slightly curved l. representing an area of preliminary calcification at the junction of the epiphysis and diaphysis of a long bone, related to syphilitic epiphysitis. white l. 1. SYN: linea alba. 2. a pale streak appearing within 30 to 60 seconds after stroking the skin with a fingernail, and lasting for several minutes; regarded as a sign of diminished arterial tension. SYN: Sergent white l.. white l. of anal canal a bluish pink, narrow, wavy zone in the mucosa of the anal canal below the pectinate l. at the level of the interval between the subcutaneous part of the external sphincter and the lower border of the internal sphincter, said to be palpable. SYN: Hilton white l.. white l. of Toldt 1. lateral reflection of posterior parietal pleura of abdomen over the mesentery of the ascending and descending colon. 2. junction of parietal peritoneum with Denonvilliers fascia. Z l. a cross-striation bisecting the I band of striated muscle myofibrils and serving as the anchoring point of actin filaments at either end of the sarcomere. SYN: intermediate disk, Z band, Z disk. lines of Zahn riblike markings seen by the naked eye on the surface of antemortem thrombi; they consist of a branching framework of platelets and fibrin separating the coagulated blood cells. SYN: striae of Zahn. Zöllner lines figures devised to show the possibility of optical illusions; a common one consists of two parallel lines which are met by numerous short lines obliquely placed; the parallel lines then seeming to converge or diverge.

linea, gen. and pl. lineae (lin′e-a, -e-e) [TA]
SYN: line. [L.] l. alba [TA] a fibrous band running vertically the entire length of the midline of the anterior abdominal wall, receiving the attachments of the oblique and transverse abdominal muscles. SYN: Hunter line, white line (1) . l. anorectalis [TA] SYN: anocutaneous line. l. arcuata [TA] SYN: arcuate line. l. arcuata ossis ilii [TA] SYN: arcuate line of ilium. l. arcuata vaginae musculi recti abdominis [TA] SYN: arcuate line of rectus sheath. SEE ALSO: rectus sheath, posterior layer of rectus sheath. l. aspera [TA] a rough ridge with two pronounced lips running down the posterior surface of the shaft of the femur; the lateral lip of the l. aspera is a continuation of the gluteal tuberosity, the medial lip of the intertrochanteric line; it affords attachment to the vastus medialis, adductor longus, adductor magnus, adductor brevis, the short head of the biceps, and the vastus lateralis muscles as well as to the intermuscular septa of the thigh. SYN: rough line. lineae atrophicae SYN: striae cutis distensae, under stria. l. axillaris anterior [TA] SYN: anterior axillary line. l. axillaris media [TA] SYN: midaxillary line. l. axillaris posterior [TA] SYN: posterior axillary line. l. corneae senilis SYN: arcus senilis. lineae distractionis [TA] SYN: tension lines, under line. l. epiphysialis [TA] SYN: epiphysial line. l. glutea anterior anterior gluteal line. See gluteal lines, under line. lineae gluteae [TA] SYN: gluteal lines, under line. l. glutea inferior inferior gluteal line. See gluteal lines, under line. l. glutea posterior posterior gluteal line. See gluteal lines, under line. l. intercondylaris femoris [TA] SYN: intercondylar line of femur. l. intermedia cristae iliacae [TA] SYN: intermediate zone of iliac crest. l. interspinalis SYN: interspinal line. SEE ALSO: interspinous plane. l. intertrochanterica [TA] SYN: intertrochanteric line. l. intertubercularis SYN: intertubercular line. SEE ALSO: intertubercular plane. l. mammillaris [TA] SYN: mammillary line. l. mediana anterior [TA] SYN: anterior median line. l. mediana posterior [TA] SYN: posterior median line. l. medio-axillaris SYN: midaxillary line, midaxillary line. l. medioclavicularis [TA] SYN: midclavicular line. l. musculi solei [TA] SYN: soleal line. l. mylohyoidea [TA] SYN: mylohyoid line. l. nigra the l. alba in pregnancy, which then becomes pigmented. SYN: black line. l. nuchae inferior [TA] SYN: inferior nuchal line. l. nuchae mediana SYN: external occipital crest. l. nuchae superior [TA] SYN: superior nuchal line. l. nuchae suprema [TA] SYN: highest nuchal line. l. obliqua [TA] SYN: oblique line. l. obliqua cartilaginis thyroideae [TA] SYN: oblique line of thyroid cartilage. l. obliqua mandibulae [TA] SYN: oblique line of mandible. l. parasternalis [TA] SYN: parasternal line. l. paravertebralis [TA] SYN: paravertebral line. l. pectinata canalis analis [TA] SYN: pectinate line. l. pectinea femoris [TA] SYN: pectineal line of femur. l. poplitea SYN: soleal line. l. postaxillaris SYN: posterior axillary line, posterior axillary line. l. preaxillaris SYN: anterior axillary line, anterior axillary line. l. scapularis [TA] SYN: scapular line. l. semicircularis SYN: arcuate line of rectus sheath. l. semilunaris [TA] the slight groove in the external abdominal wall parallel to the lateral edge of the rectus sheath. SYN: semilunar line, Spigelius line. l. spiralis SYN: intertrochanteric line. l. splendens a thickened band of pia mater along the midline of the anterior surface of the spinal cord. SYN: Haller line. l. sternalis [TA] SYN: sternal line. l. subcostalis SYN: subcostal line. SEE ALSO: subcostal plane. l. supracristalis SYN: supracrestal line. SEE ALSO: supracrestal plane. l. temporalis inferior ossis parietalis [TA] SYN: inferior temporal line of parietal bone. l. temporalis ossis frontalis [TA] SYN: temporal line of frontal bone. l. temporalis superior ossis parietalis [TA] SYN: superior temporal line of parietal bone. l. terminalis of pelvis [TA] an oblique ridge on the inner surface of the ilium and continued on the pubis, which forms the lower boundary of the iliac fossa; it separates the true from the false pelvis. SYN: l. terminalis pelvis [TA] , iliopectineal line, terminal line. l. terminalis pelvis [TA] SYN: l. terminalis of pelvis. lineae transversae ossis sacri [TA] SYN: transverse ridges of sacrum, under ridge. l. trapezoidea [TA] SYN: trapezoid line.

lineage (lin′aj, lin′e-aj)
Descent in a line from a common progenitor or source. [O. Fr. ligne, line of descent]

linear (lin′e-ar)
Pertaining to or resembling a line.

linearity (lin-e-ar′i-te)
A relationship between two quantities whereby a change in one causes a directly proportional change in the other. [L. linearis, linear, fr. linea, line]

Practice of successive inbreeding of closely related individuals with the object of concentrating desirable or scientifically interesting genetic characteristics of some individual or group.

liner (li′ner)
A layer of protective material. asbestos l. a layer of asbestos used to line a dental casting ring so that during the heating and expansion of the investment the compression of the l. will free the investment from the restraint of the ring. cavity l. SYN: varnish (dental).

Abbreviation for long interspersed elements, under element.

Hans, U.S. physical chemist, *1907. See L.-Burk equation, L.-Burk plot.

Per Henrik, Swedish hygienist, 1776–1839. See L. method.

Lingelsheimia (lin′jels-hii′me-a)
SYN: Acinetobacter. [W. von Lingelsheim] L. anitrata SYN: Acinetobacter calcoaceticus.

lingua, gen. and pl. linguae (ling′gwa, ling′gwe)
1. SYN: tongue (1) . 2. SYN: tongue (2) . [L. tongue] l. cerebelli SYN: lingula of cerebellum. l. fissurata SYN: fissured tongue. l. frenata a tongue with a very short frenum constituting tongue-tie. l. geographica l. nigra SYN: black tongue. l. plicata SYN: fissured tongue.


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