- 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.- 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..- 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).- Beau lines transverse grooves on the fingernails following severe febrile disease, malnutrition, trauma, myocardial infarction, etc.- bismuth l. a black zone on the free marginal gingiva, often the first sign of poisoning from prolonged parenteral administration of bismuth.- 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.- 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.- 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.- 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.- 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.- 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.- developmental lines SYN: developmental grooves, under groove.- 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.- Feiss l. a l. running from the medial malleolus to the plantar aspect of the first metatarsophalangeal joint.- Fleischner lines coarse linear shadows on a chest radiograph, indicating bands of subsegmental atelectasis.- 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., Gennari band, Gennari stria, stripe of Gennari.- 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.- 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.- 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.- 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.- 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.- 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.- 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.- 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].- 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.- isoelectric l. the baseline of the electrocardiogram, recorded in the TP interval during rhythms with P waves.- Kerley A lines images of deep interlobular septa; longer, thicker, and more central than Kerley B lines; usually in upper lobes.- 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.- 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.- 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].- 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.- 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].- 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].- 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.- popliteal l. SYN: soleal 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.- 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.- Roser-Nélaton l. SYN: Nélaton l..- rough l. SYN: linea aspera.- 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].- 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.- 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..- Spigelius l. SYN: linea semilunaris.- 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.- 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. 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].- 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.- 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.- 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.- 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.* * *long interspersed repetitive element
* * *line 'līn n2) a strain produced and maintained esp. by selective breeding or biological culture3) a narrow short synthetic tube (as of plastic) that is inserted approximately one inch into a vein (as of the arm) to provide temporary intravenous access for the administration of fluid, medication, or nutrients
* * *(līn) [L. linea] 1. a thin straight mark; a stripe, streak, or narrow ridge. 2. in anthropometry, such a mark (often imaginary) traced between different anatomical landmarks. See also axis and plane (def. 1).
For descriptions of anatomical terms, see also under linea.
Medical dictionary. 2011.