median line

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1. a stripe, streak, or narrow ridge; sometimes only an imaginary connector between two anatomic landmarks. Called also linea. adj., adj lin´ear.
2. tubing on a catheter.
absorption l's dark lines in the spectrum due to absorption of light by the substance through which the light has passed.
arterial line a monitoring system that uses an artery for access and consists of a catheter in the artery, pressure tubing, a transducer, and an electronic monitoring device. The most common uses of arterial lines are for monitoring of systemic blood pressure and obtaining arterial blood for analysis.
Beau's l's transverse lines or grooves in the nail plate caused by various systemic and local traumatic factors.
Beau's line. From Polaski and Tatro, 1996.
bismuth line a thin blue-black line along the gingival margin in bismuth poisoning.
blue line lead line.
cement line a line visible in microscopic examination of bone in cross section, marking the boundary of an osteon (haversian system).
cervical line anatomical designation for the cementoenamel junction.
cleavage l's Langer's lines.
line of Douglas a crescentic line marking the termination of the posterior layer of the sheath of the rectus abdominis muscle.
l's of election lines of expression.
epiphyseal line one on the surface of an adult long bone, marking the junction of the epiphysis and diaphysis.
l's of expression the natural skin lines and creases of the face and neck; the preferred lines of incision in facial and cervical surgery.
gingival line
1. a line determined by the level to which the gingiva extends on a tooth; called also gum line.
2. any linear mark visible on the surface of the gingiva.
gluteal line any of the three rough curved lines (anterior, inferior, and posterior) on the gluteal surface of the ala of the ilium.
gum line gingival line (def. 1).
hot line see hot line.
iliopectineal line the ridge on the ilium and pubes showing the brim of the true pelvis.
incremental l's lines supposedly showing the successive layers deposited in a tissue, as in the tooth enamel.
intertrochanteric line one running obliquely from the greater to the lesser trochanter on the anterior surface of the femur.
Langer's l's linear clefts in the skin indicative of the direction of the fibers; they correspond closely to the creases of the body but vary with body configuration. Lines of incision made parallel to them are thought to heal more efficiently. Called also cleavage lines.
lead line a purple-blue line at the edge of the gums in chronic lead poisoning; called also blue line.
lip line a line on the teeth at the level to which the margin of either lip extends.
median line an imaginary vertical line dividing the body equally into right and left parts.
milk line the line of thickened epithelium in the embryo along which the mammary glands are developed.
mylohyoid line a ridge on the inner surface of the lower jaw from the base of the symphysis to the ascending rami behind the last molar tooth.
nuchal l's three lines (inferior, superior, and highest) on the outer surface of the occipital bone.
pectinate line one marking the junction of the zone of the anal canal lined with stratified squamous epithelium and the zone lined with columnar epithelium.
semilunar line a curved line along the lateral border of each rectus abdominis muscle, marking the meeting of the aponeuroses of the internal oblique and transverse abdominal muscles.
Shenton's line a curved line seen in radiographs of the normal hip, formed by the top of the obturator foramen; it is used to determine the relationship between the head of the femur and the acetabulum.
temporal l's curved ridges, inferior and superior, on the external surface of the parietal bone, continuous with the temporal line of the frontal bone, a ridge that extends upward and backward from the zygomatic process of the frontal bone.
terminal line one on the inner surface of each pelvic bone, from the sacroiliac joint to the iliopubic eminence anteriorly, separating the false from the true pelvis.
visual line a line from the point of vision of the retina to the object of vision; called also visual axis.
Miller-Keane Encyclopedia and Dictionary of Medicine, Nursing, and Allied Health, Seventh Edition. © 2003 by Saunders, an imprint of Elsevier, Inc. All rights reserved.

an·te·ri·or me·di·an line

the line of intersection of the midsagittal plane with the anterior surface of the body.
Synonym(s): linea mediana anterior [TA]
Farlex Partner Medical Dictionary © Farlex 2012


A flat surface.
aperture plane A plane that passes through the aperture of an optical system.
apparent frontoparallel plane (AFPP) Plane passing through the fixation point and containing all other points judged to appear in the same frontal plane. At about 1 metre from the eye it more or less coincides with a frontal plane; this is the abathic distance. Closer to 1 metre it is often a concave surface with its concavity turned towards the observer and beyond 1 metre it is a convex surface with its convexity turned towards the observer. See Hering-Hillebrand deviation; horopter.
cardinal plane's Planes, normal to the optical axis, which pass through the cardinal points of a lens or optical system. They are the focal planes, the nodal planes and the principal planes. (Sometimes, this definition also includes the object and image planes.) See cardinal points.
equatorial plane Vertical plane passing through the centre of curvature of the large circle of the eyeball, perpendicular to the optical axis and which divides the eyeball into anterior and posterior halves. See anterior segment of the eye; Listing's plane.
plane of fixation See plane of regard.
focal plane A plane, perpendicular to the optical axis, which passes through one of the focal points of an optical system. See principal focus.
frontal plane A vertical plane perpendicular to the median plane. When this plane passes through the centre of rotation of the eye it is called Listing's plane.
frontoparallel plane The frontal plane passing through the fixation point.
horizontal plane of the eye Plane, such as the xy plane, passing through the centre of rotation of the eye and dividing it into superior and inferior halves. When the eye is looking straight ahead this plane is horizontal. See subjective horizontal plane; xy plane.
image plane A plane, perpendicular to the optical axis at any axial image point of an optical system.
plane of incidence The plane containing the incident and reflected rays, and the normal to the surface at the point of incidence.
Listing's plane A frontal plane passing through the centre of rotation, which corresponds to the equatorial plane of the eye when it is looking in the straight-ahead position (Fig. P11).
median plane The vertical plane that divides the head into right and left halves.
plane mirror See plane mirror.
nodal plane A plane, perpendicular to the optical axis, which passes through one of the nodal points of an optical system (Fig. P12).
object plane A plane perpendicular to the optical axis at any axial object point of an optical system.
principal plane A plane perpendicular to the optical axis of an optical system at the point where the incident rays parallel to the optical axis intersect the refracted rays converging to the secondary focal point (secondary principal plane); or in which the refracted rays parallel to the optical axis intersect the incident rays coming from the primary focal point (primary principal plane). Each plane is an erect image of the other, and of the same size. For this reason they are sometimes also referred to as unit planes as they are conjugate planes in which the magnification is +1. In a thin lens these planes coincide at the lens (Fig. P12). See image distance; object distance; focal length; thin lens; nodal points; principal points; equivalent power.
plane of regard Plane containing the fixation point, the axes of fixation from the two eyes and the base line. Syn. plane of fixation.
sagittal plane A vertical plane parallel to the median plane as, for example, the yz plane.
spectacle plane A plane representing the orientation of the spectacle lenses relative to the eyes and passing through the posterior vertices of the two lenses. See pantoscopic angle; retroscopic angle; vertex distance.
subjective horizontal plane Plane fixed with respect to the eye, i.e. horizontal when the eye is in the primary position. See horizontal plane of the eye; primary position.
unit plane's See principal plane.
plane of vibration See polarized light.
visual plane The plane containing the two visual axes.
xy plane Horizontal plane of the eye containing both the x- and y-axes (Fig. P11). See anteroposterior axis; transverse axis.
yz plane Vertical plane of the eye containing both the y- and z-axes (Fig. P11). See anteroposterior axis; vertical axis.
Fig. P11 Listings plane and the axes of Fickenlarge picture
Fig. P11 Listing's plane and the axes of Fick
Fig. P12 Primary and secondary principal planes HP and H′P′ of a thick lens in air (PF, anterior focal length; P′F′, posterior focal length; SF, front vertex focal length; S′F′, back vertex focal length; SF′ 1 , back focal length of the first surface D 1 ; S′F 2 , front focal length of the second surface D 2 ; N and N′, nodal points)enlarge picture
Fig. P12 Primary and secondary principal planes HP and H′P′ of a thick lens in air (PF, anterior focal length; P′F′, posterior focal length; SF, front vertex focal length; S′F′, back vertex focal length; SF′1, back focal length of the first surface D1; S′F2, front focal length of the second surface D2; N and N′, nodal points)
Millodot: Dictionary of Optometry and Visual Science, 7th edition. © 2009 Butterworth-Heinemann
References in periodicals archive ?
"We have said 'OK, we're now on both sides of the median line, what kind of advantages does that bring if we were to remove the median line and let both the geologists and project teams work together on what is possible?' "We found several assets were actually not developed on the UK side, with a long distance to infrastructure ...
There is a clear understanding that since the distance between their shorelines is less than 400 nautical miles (about 740 km), the conventional limits of EEZ (Exclusive Economic Zone) cannot be applied, and therefore a median line should be drawn to mark the share of each side.
Beijing argues that Chunxiao lies in Chinese waters on the west side of the median line and that therefore, even according to the Japanese interpretation of international law, there is nothing wrong with the Chunxiao project.
In April 1978 when the third UN Conference on the Law of the Sea was still considering the argument about the principle of equity and the equidistance principle, the Chinese delegation made its stance very clear, saying that the median line or equidistant line is just one option for maritime delimitation and it shall neither be adopted as the compulsory method nor be treated as the delimitation principle.
A white median line from apex of frons to end of mesonotum bordered with blackish brown (Figs.
in Britain, has been preparing to develop the oil field which straddles the two countries' median line in cooperation with other companies, including Paladin Expro Ltd.
In short, the East Timorese argue that a seabed boundary should be based on a median line between the two countries, which would give East Timor exclusive access to the JDPA, and to a majority of the oil and gas fields.
Putin: "We agreed to begin work on drawing a median line between Russia and Azerbaijan".
What prompted the intervention was the fact that Cameroon's Memorial had arguably disregarded the median line between itself and intervenor, a position that Cameroon had never hinted at during their negotiations.
Coming to the equitable solution, the Chamber suggested that the method itself is not equitable, but solely instrumental.(96) The examples of method included (a) median line, (b) lateral equidistance, (c) line perpendicular to the coast where the territories meet, (d) line perpendicular to the general direction of the coast, (e) boundary prolonging the existing division of territorial waters, and (f) boundary prolonging the direction of the final segment of the land boundary or of its overall direction.(97) Thus, contrary to Libya-Tunisia, the equitable solution has no meaning of its own, but only effectuates the relevant criteria.
She has a long and thorough acquaintance with this region, having devoted an earlier study to the village of Bonnieres-sur-Seine, in the northwestern corner of the department.(1) A fixture of French political geography from the Revolution until a law of 1964 rearranged the administrative divisions of the Parisian basin, the mainly rural department of Seine-et-Oise, with its seat at Versailles, entirely surrounded the department of the Seine (the capital and its immediate suburbs), which was situated a little north of the median line and close to the eastern boundary of the larger department; hence the "Parisian countryside" of the book's title.
A horizontal line divides the upper lip from the lower lip, and a median line partitions the right and left sides.