line (lIn)

1. A mark, strip, or streak. In anatomy, a long narrow mark, strip, or streak distinguished from the adjacent tissues by a color, texture, or elevation. See also line. 2. A unit of measurement used by histologists in the 19th century; it varied in different countries from 1 / 10 to 1 / 12 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.linea [NA]; [L. linea, a linen thread, a string, line, fr. linum, flax]
absorption l.'s the dark l.'s 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 l.'s l.'s 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's lateral sinus l. a l. dividing the angle formed by the anterior edge of the mastoid process and the temporal l.
anocutaneous l. pectinate l
anterior axillary l. a vertical line extending inferiorly from the anterior axillary fold.linea axillaris anterior [NA], linea preaxillaris [NA], preaxillary l;
anterior junction l. radiographic projection of the mediastinal tissue septum between the upper lobes behind the sternum.
anterior median l. the line of intersection of the midsagittal plane with the anterior surface of the body.linea mediana anterior [NA];
arcuate l. an arching or bow-shaped l. See arcuate l. of ilium, arcuate l. of rectus sheath.linea arcuata [NA];
arcuate l. of ilium the iliac portion of the linea terminalis of the bony pelvis.linea arcuata ossis ilii [NA];
arcuate l. of rectus sheath a crescentic line, not always clearly defined, which marks the lower limit of the posterior layer of the sheath of the rectus abdominis muscle.linea arcuata vaginae musculi recti abdominis [NA], Douglas' l., linea semicircularis, semicircular l;
arterial l. an intra-arterial catheter.
axillary l. See anterior axillary l., midaxillary l., posterior axillary l.
Baillarger's l.'s two laminae of white fibers that course parallel to the surface of the cerebral cortex and are visible as outer and inner l.'s in sections cut perpendicular to the surface; the l. of Gennari in the calcarine cortex represents the outer of these lines.Baillarger's bands;
base l. a l. approximating the base of the skull, passing from the infraorbital ridge to the midline of the occiput, intersecting the superior margin of the external auditory meatus; the skull is in the anatomical position when the base line lies in the horizontal plane.orbitomeatal l;
basinasal l. a l. connecting the basion and the nasion.nasobasilar l;
Beau's l.'s transverse depressions on the fingernails following severe febrile disease, malnutrition, trauma, myocardial infarction, etc.
l. of Bechterew 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. linea nigra
blue l. a bluish l. along the free border of the gingiva, occurring in chronic heavy metal poisoning.
Bolton-nasion l. Bolton plane
Brödel's 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's l. a bluish l. on the free border of the gingiva, occurring in lead poisoning.
calcification l.'s of Retzius incremental l.'s of rhythmic deposition of successive layers of enamel matrix during development.l.'s of Retzius;
Camper's 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's 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's l. the anteroposterior l. of the corpus callosum as appearing on median section of the brain.
Clapton's l. a greenish discoloration of the marginal gingiva in cases of chronic copper poisoning.
cleavage l.'s lines which 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.Langer's l.'s;
Conradi's 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 l.'s of Owen Owen's l.'s
Correra's l. pleural l.'s
costoclavicular l. parasternal l
costophrenic septal l.'s Kerley B l.'s
Crampton's 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's l. the l. passing between the opisthion and the basion. See also Daubenton's angle, Daubenton's 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; line marking the limits of an old retinal detachment.
Dennie's l. an accentuated line or fold below the margin of the lower eyelid; characteristic in atopic dermatitis.Dennie's infraorbital fold;
dentate l. pectinate l
developmental l.'s developmental grooves, under groove
Douglas' l. arcuate l. of rectus sheath
Eberth's l.'s l.'s appearing between the cells of the myocardium when stained with silver nitrate.
Egger's 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. the line of junction of the epiphysis and diaphysis of a long bone where growth in length occurs.linea epiphysialis [NA], synchondrosis epiphyseos;
established cell l. cells that demonstrate the potential for indefinite subculture in vitro.
Farre's 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.
l. of fixation a l. joining the object (or point of fixation) with the fovea.
Fleischner l.'s coarse linear shadows on a chest radiograph, indicating bands of subsegmental atelectasis.
Fraunhofer's l.'s a number of the most prominent of the absorption l.'s of the solar spectrum.
fulcrum l. an imaginary l. around which a removable partial denture tends to rotate.rotational axis;
Futcher's l. a dorso-ventral line of pigmentation occurring symmetrically and bilaterally for about 10 cm along the lateral edge of the biceps muscle, seen in some blacks.Voigt's l.'s;
l. of Gennari a prominent white line appearing in perpendicular sections of the visual cortex (Brodmann's area 17) at about mid-thickness of the cortical gray matter, corresponding to the particularly well developed outer line of Baillarger of that cortical area, and composed largely of tangentially disposed intracortical association fibers.Gennari's band, Gennari's stria, stripe of Gennari;
germ l. a collection of haploid cells derived from the specialized cells of the primitive gonad.
gluteal l. one of three rough curved lines on the outer surface of the ala of the ilium: anterior (or middle) 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.linea glutea [NA];
Granger's l. on lateral skull radiographs, the l. produced by the groove of the optic chiasm or sulcus prechiasmatis.
growth arrest l.'s dense l.'s parallel to the growth plates of long bones on radiographs, representing temporary slowing or cessation of longitudinal growth.Harris' l.'s;
Gubler's l. the level of the superficial origin of the trigeminus on the pons, a lesion below which causes Gubler's paralysis.
gum l. the position of the margin of the gingiva in relation to the teeth in the dental arch.
Haller's l. linea splendens
Hampton l. a thin radiolucent band across the neck of a contrast-filled benign gastric ulcer, indicating mucosal edema. Cf. Carman's sign.
Harris' l.'s growth arrest l.'s
Head's l.'s bands of cutaneous hyperesthesia associated with acute or chronic inflammation of the viscera.Head's zones, tender l.'s, tender zones;
Hensen's l. H band
highest nuchal l. a line above and parallel to the superior nuchal line on the external surface of the occipital bone; it gives attachment to the epicranial aponeurosis and occipitalis muscle.linea nuchae suprema [NA];
high lip l. the greatest height to which the lip is raised in normal function or during the act of smiling broadly.
Hilton's white l. 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's 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's l. linea alba
Hunter-Schreger l.'s Hunter-Schreger bands, under band
iliopectineal l. linea terminalis
imbrication l.'s of von Ebner incremental l.'s in the dentin of the tooth that reflect variations in mineralization during dentin formation; the distance between the l.'s corresponds to the daily rate of dentin formation.incremental l.'s of von Ebner;
incremental l.'s 1. in the enamel, calcification l.'s of Retzius; 2. in the dentin, imbrication or incremental l.'s of von Ebner, and Owen's l.'s.
incremental l.'s of von Ebner imbrication l.'s of von Ebner
inferior nuchal l. a ridge that extends laterally from the external occipital crest toward the jugular process of the occipital bone.linea nuchae inferior [NA];
inferior temporal l. the lower of two curved lines on the parietal bone; it marks the outer limit of attachment of the temporalis muscle.linea temporalis inferior [NA], temporal ridge;
infracostal l. subcostal plane
intercondylar l. of femur 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.linea intercondylaris femoris [NA];
intermediate l. of iliac crest the line on the crest of the ilium between the outer and inner lips, for origin of internal oblique muscle.linea intermedia cristae iliacae [NA];
internal oblique l. mylohyoid l
interspinal l. l. passing through both anterior superior iliac spines indicating the interspinal plane.linea interspinalis [NA];
intertrochanteric l. a rough line 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.linea intertrochanterica [NA], linea spiralis, spiral l;
intertubercular l. l. passing through tubercles of both iliac crests, indicating the intertubercular plane.linea intertubercularis [NA];
isoelectric l. the baseline of the electrocardiogram.
l. of Kaes band of Kaes-Bechterew
Kerley A l.'s images of deep interlobular septa; longer, thicker, and more central than Kerley B l.'s; usually in upper lobes.
Kerley B l.'s fine peripheral septal l.'s.costophrenic septal l.'s;
Kerley C l.'s a nonspecific fine reticular pattern on chest radiographs.
Kilian's l. a transverse l. marking the promontory of the pelvis.
Langer's l.'s cleavage l.'s
Lanz's l. interspinal plane
lateral l. See lateral line system.
lead l. deposits of lead sulfide in the gingiva in areas of chronic inflammation.
Looser's l.'s radiolucent bands in the cortex of a bone; usually indicates osteomalacia.Looser's 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.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.
mamillary l. a vertical line passing through the nipple on either side.linea mamillaris [NA], nipple l;
mammary l. a transverse l. drawn between the two nipples.
McKee's 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. See anterior median l., posterior median l.
Mees' l.'s horizontal white bands of the nails seen in chronic arsenical poisoning, and occasionally in leprosy.Mees' stripes;
mercurial l. a bluish brown pigmentation seen at the gingival margin and associated with mercury poisoning (mercurial stomatitis).
Meyer's l. a l. through the axis of the big toe and passing the midpoint of the heel in a normal foot.
midaxillary l. a vertical line intersecting a point midway between the anterior and posterior axillary folds or lines.linea axillaris media [NA], linea medio-axillaris [NA], middle axillary l;
midclavicular l. a vertical line passing through the midpoint of the clavicle.linea medioclavicularis [NA];
middle axillary l. midaxillary l
milk l. mammary ridge
Monro-Richter l. a l. passing from the umbilicus to the anterior superior iliac spine. McBurney's point occurs on this line.Monro's l., Richter-Monro l;
Monro's l. Monro-Richter l
Muehrcke's l.'s white l.'s, parallel with the lanula and separated from each other by normal pink areas; associated with hypoalbuminemia; the l.'s do not move outward with nail growth, but disappear when the serum albumen returns to normal.
mylohyoid l. 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.linea mylohyoidea [NA], internal oblique l., mylohyoid ridge;
nasobasilar l. basinasal l
Nélaton's l. a l. drawn from the anterior superior iliac spine to the tuberosity of the ischium; normally the great 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.Roser-Nélaton l;
neonatal l. in deciduous teeth, a l. of demarcation between prenatal and postnatal enamel.neonatal ring;
nipple l. mamillary l
Obersteiner-Redlich l. Obersteiner-Redlich zone
oblique l. a diagonal, sloping or slanting l.; a l. which is neither parallel nor perpendiculr, neither horizonal nor vertical. See oblique l. of mandible, oblique l. of thyroid cartilage.linea obliqua [NA];
oblique l. of mandible 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.linea obliqua mandibulae [NA];
oblique l. of thyroid cartilage a ridge on the outer surface of the thyroid cartilage that gives attachment to the sternothyroid and thyrohyoid muscles.linea obliqua cartilaginis thyroidea [NA];
l. of occlusion the alignment of the occluding surfaces of the teeth in the horizontal plane. See also occlusal plane.
Ogston's 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's 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. base l
Owen's l.'s accentuated incremental l.'s in the dentin thought to be due to disturbances in the mineralization process.contour l.'s of Owen;
paraspinal l. radiographic image of the interface between the lung and paravertebral soft tissues.
parasternal l. a vertical line equidistant from the sternal and midclavicular lines.linea parasternalis [NA], costoclavicular l;
paravertebral l. a vertical line corresponding to the tips of the transverse processes of the vertebrae.linea paravertebralis [NA];
Paris l. a unit of microscopic measurement as used in Kölliker's Mikroskopische Anatomie; it was equal to 0.0888138 of an inch.
Paton's l.'s fine l.'s on the surface of the retina, concentric to a swollen disc.striae retinae;
pectinate l. the l. between the simple columnar epithelium of the rectum and the stratified epithelium of the anal canal.linea anocutanea [NA], anocutaneous l., dentate l;
pectineal l. 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 line and inferiorly with the medial lip of the linea aspera.linea pectinea [NA];
pectineal l. of pubis pecten pubis
pleural l.'s on a chest radiograph, the shadow of the soft tissues between the aerated lung and the bones of the thorax.Correra's l;
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's l. a l. extending from the nasion to the lambda.
popliteal l. soleal l
postaxillary l. posterior axillary l
posterior axillary l. a vertical line extending inferiorly from the posterior axillary fold.linea axillaris posterior [NA], linea postaxillaris [NA], 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. the line of intersection of the midsagittal plane with the posterior surface of the body.linea mediana posterior [NA];
Poupart's 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. anterior axillary l
Reid's 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.
l.'s of Retzius calcification l.'s of Retzius
Richter-Monro l. Monro-Richter l
Roser-Nélaton l. Nélaton's l
rough l. linea aspera
sagittal l. any l. parallel to the midline, indicating a sagittal plane.
Salter's incremental l.'s transverse l.'s 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. a vertical line passing through the inferior angle of the scapula.linea scapularis [NA];
Schreger's l.'s Hunter-Schreger bands, under band
semicircular l. 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. linea semilunaris
septal l.'s radiographic images of thickened interlobular septa, most often along the lateral border of lung, extending to pleura; Kerley A and B l.'s; usually caused by septal edema and fibrosis, also carcinomatosis.
Sergent's white l. white l. (2)
Shenton's 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. a ridge which extends obliquely downward and medially across the back of the tibia from the fibular articular facet; it gives origin to the soleus muscle.linea musculi solei [NA], l. for soleus muscle, linea poplitea, popliteal l;
l. for soleus muscle soleal l
Spigelius' l. linea semilunaris
spiral l. intertrochanteric l
stabilizing fulcrum l. an imaginary l. connecting occlusal rests, around which l. the denture tends to rotate under masticatory force.
sternal l. a vertical line corresponding to the lateral margin of the sternum.linea sternalis [NA];
Stocker's 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.linea subcostalis [NA];
superior nuchal l. 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.linea nuchae superior [NA];
superior temporal l. the upper of two curved lines on the parietal bone; the temporal fascia is attached to it.linea temporalis superior [NA], temporal ridge;
supracrestal l. a transverse l. transecting the high point of both iliac crests, indicating the supracristal plane. See also supracristal plane.linea supracristalis [NA];
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.clasp guideline, Cummer's guideline;
Sydney l. Sydney crease
sylvian l. the l. of the posterior limb of the lateral sulcus (sylvian fissure) of the cerebral cortex.
temporal l. See inferior temporal l., superior temporal l.
tender l.'s Head's l.'s
terminal l. linea terminalis
Topinard's l. a l. running between the glabella and the mental point.
tram l.'s the images of bronchial walls, usually thickened; colloq., British.radiographic parallel line shadows;
transverse l.'s of sacrum one of four ridges that cross the pelvic surface of the sacrum; these mark the positions of the intervertebral disks between the bodies of the five sacral vertebrae in the immature bone.lineae transversa ossi sacri [NA];
trapezoid l. the area on the inferior surface of the clavicle near its lateral extremity on which the trapezoid ligament attaches.linea trapezoidea [NA], trapezoid ridge;
Ullmann's l. the l. of displacement in spondylolisthesis.
Vesling's l. scrotal raphe
vibrating l. the imaginary l. across the posterior part of the palate, marking the division between the movable and immovable tissues.
l. of vision visual axis
Voigt's l.'s Futcher's l
Wegner's 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. 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.Sergent's 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.Hilton's 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 Denonvillieri's 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.intermediate disk, Z band, Z disk;
l.'s 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.striae of Zahn;
Zöllner's l.'s figures devised to show the possibility of optical illusions; a common one consists of two parallel l.'s which are met by numerous short lines obliquely placed; the parallel lines then seeming to converge or diverge.


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