axis

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Related to coronal axis: frontal plane, Transverse axis, sagittal axis

axis

 [ak´sis] (pl. ax´es)
1. a line through a center of a body, or about which a structure revolves.
the second cervical vertebra. adj., adj ax´ial.
2. the position of the cylindrical part of a lens, used for correcting astigmatism; the range of values is from 0° to 180°.
celiac axis celiac trunk.
dorsoventral axis one passing from the posterior to the anterior surface of the body.
electrical axis of heart the preponderant direction of current flow through the heart, a consequence of the electromotive forces within the heart. It may be computed on either an instantaneous basis or a mean basis.
frontal axis an imaginary line running from right to left through the center of the eyeball.
axis of heart a line passing through the center of the base of the heart to the apex.
instantaneous electrical axis the electrical axis of the heart determined at a given point in time.
lead axis the imaginary direct line between the two electrodes of the bipolar leads or between the positive electrode and the reference point of the unipolar leads.
mean electrical axis the average direction of the activation or repolarization process during the cardiac cycle; it may be determined for any deflection (P, QRS, ST-T) and in the frontal, transverse, or sagittal plane.
optic axis
1. a line connecting the center of the anterior curvature of the cornea (anterior pole) with that of the posterior curvature of the sclera (posterior pole).
2. the hypothetical straight line passing through the centers of curvature of the front and back surfaces of a simple lens.
phlebostatic axis a point located by drawing an imaginary line from the fourth intercostal space at the sternum and finding its intersection with an imaginary line drawn down the center of the chest below the axillae.
Phlebostatic axis.
sagittal axis an imaginary line extending through the anterior and posterior poles of the eye.
visual axis an imaginary line passing from the midpoint of the visual field to the fovea centralis.
Axes of the eye. From Dorland's , 2000.

ax·is (ax),

, pl.

ax·es

(ak'sis, ak'sēz), Do not confuse this word with access.
1. A straight line joining two opposing poles of a spheric body, about which the body may revolve.
2. The central line of the body or any of its parts.
3. The second cervical vertebra.
5. The central nervous system.
6. An artery that divides, immediately on its origin, into a number of branches, for example, celiac axis.
[L. axle, axis]

axis

/ax·is/ (ak´sis) pl. ax´es   [L.]
1. a line through the center of a body, or about which a structure revolves; a line around which body parts are arranged.
2. the second cervical vertebra.ax´ial
Enlarge picture
Axis. (A), (Top) transverse aspect; (bottom) superior aspect. (B), Position.

basibregmatic axis  the vertical line from the basion to the bregma.
basicranial axis  a line from basion to gonion.
basifacial axis  a line from gonion to subnasal point.
binauricular axis  a line joining the two auricular points.
celiac axis  see under trunk.
dorsoventral axis  one passing from the back to the belly surface of the body.
electrical axis of heart  the resultant of the electromotive forces within the heart at any instant.
frontal axis  an imaginary line running from right to left through the center of the eyeball.
axis of heart  a line passing through the center of the base of the heart and the apex.
optic axis  the hypothetical straight line passing through the centers of curvature of the front and back surfaces of a simple lens.
Enlarge picture
Axes of the eye.
visual axis  an imaginary line passing from the midpoint of the visual field to the fovea centralis.
Enlarge picture
Axes of the eye.

axis

(ăk′sĭs)
n. pl. axes (ăk′sēz′)
1. A straight line about which a body or geometric object rotates or may be conceived to rotate.
2. A center line to which parts of a structure or body may be referred.
3. Anatomy
a. The second cervical vertebra on which the head turns.
b. Any of various central structures, such as the spinal column, or standard abstract lines used as a positional referent.

axis

pl. axes [ak′sēz]
Etymology: Gk, axon, axle
1 (in anatomy) a line that passes through the center of the body, or a part of the body, such as the frontal axis, binauricular axis, and basifacial axis.
2 the second cervical vertebra, about which the atlas rotates, allowing the head to be turned, extended, and flexed. Also called epistropheus, odontoid vertebra.

axis

Anatomy 
The second bone of the vertebrae (C2), which contains a distinct bony protuberance, the odontoid process (dens), on which the first cervical vertebra (C1, the atlas), which carries the head, rotates.

Significance, execution
During judicial hangings, the odontoid process typically breaks off and is forced into the medulla oblongata, which contains the cardiac, respiratory and vasomotor centres that control involuntary functions (e.g., breathing, heart rate and blood pressure), usually resulting in instant death.

Medpspeak
(1) A central or straight line between two structures.
(2) A functional centre between two or more physiologically related activities—e.g., brain-gut axis, hypothalamic-pituitary-adrenal axis.

axis

Medtalk A central or straight line between two structures. See Brain-gut axis, Hypothalamic-pituitary-adrenal axis.

ax·is

, pl. axes (ak'sis, ak'sēz)
1. A straight line joining two opposing poles of a spheric body, about which the body may revolve.
2. The central line of the body or any of its parts.
3. The vertebral column.
4. The central nervous system.
5. The second cervical vertebra.
Synonym(s): epistropheus, vertebra C2, vertebra dentata.
6. An artery that divides, immediately on its origin, into a number of branches, e.g., celiac axis.
See: trunk

axis

1. The second of the vertebrae of the spine, upon which the skull and first vertebra (ATLAS) can rotate. The axis bone has a short, stout vertical peg called the odontoid process around which the atlas can rotate.
2. An imaginary central line of a part or of the body.
3. The meridian in a CYLINDRICAL LENS that possesses no optical power. The curve of maximal power is at right angles to the axis.

Axis

A line that passes through the center of the body or body part.
Mentioned in: Fractures

axis,

n 1. an imaginary line around which motion occurs, as in an axis of rotation.
2. C2, the second cervical vertebra, around whose odontoid process the atlas rotates. See also atlas.
axes, transverse,
n axes located at the junctions of the frontal and horizontal planes, around which nutation and counternutation occur. Also called
z axes.
axis of rib motion,
n an imaginary line through the costovertebral and costotransverse rib articulations.
axis, anterior-posterior,
n axis located at the junction of the horizontal and sagittal planes. Also called the
x axis.
axis, anteroposterior rib (anˈ·t·rō·p·stēˑ·rē·ōr ribˑ aˑ·ksis),
n the imaginary line crossing between the sternum and the spinal column, about which the ribs rotate in bucket handle rib motion. See also axis of rib motion and bucket handle rib motion.
axis, hypothalamic-pituitary adrenal (HPA axis) (hī·pō·th·laˑ·mik pi·tōōˑ·i·ta·rē ·drēˑ·nl aˑ·ksis),
n major component of the neuroendocrine system that controls reactions to stress and manages metabolic function; involves interactions of the hypothalamus, pituitary gland, and adrenal glands.
axis, inferior transverse,
n a hypothetical axis passing from side to side through the lower auricular surface of the ilia and sacrum, describing iliac motion on the sacrum. Proposed by osteopathic physician Fred Mitchell, Sr. Also called the
innominate axis.
axis, longitudinal,
n a hypothetical axis located at the junction of a frontal and the median-sagittal planes. See also vertical axis.
axis, middle transverse,
n hypo-thetical axis for the nutation/counternutation of the sacrum, located horizontally through the front of the sacrum at the second segment. Proposed by osteopathic physician Fred Mitchell, Sr.
axis, postural,
n See axis, middle transverse.
axis, respiratory,
n See axis, superior transverse.
axis, sacral motion,
n movement of the sacrum around any of its axes.
axis, superior transverse,
n hypothetical axis around which involuntary sacral movement is believed to occur during the craniosacral cycle. The axis passes through the articular processes behind the dura mater's attachment point in the second vertebral segment of the sacrum. Proposed by osteopathic physician Fred Mitchell, Sr.
axis, vertical,
n axis located at the junction of the frontal and sagittal planes. Also called the
y axis. See also axis, longitudinal.

axis 

A real or imaginary straight line about which a body or system can rotate, or about which a body or system is symmetrical.
achromatic axis A line in the eye along which light passes through all the optical elements and emerges without chromatic dispersion. Although it may lie close to the optical axis it does not necessarily coincide with it. See chromostereopsis; dispersion; chromatic parallax.
anteroposterior axis A line passing through the anterior and posterior poles and the centre of rotation of the eye. It is perpendicular to the transverse (or x-axis) and the vertical (or z-axis). Torsional movements occur around this axis. Syn. sagittal axis; y-axis. See centre of rotation of the eye; poles of the eyeball; torsion.
cylinder axis 1. A line of zero curvature on a cylindrical surface. 2. That principal meridian of a planocylinder in which the power is zero. See astigmatic lens.
axis's of Fick Three mutually perpendicular axes which intersect at the centre of rotation of the eye. They are the x-, y-, and z-axes. Syn. primary axes of Fick. See vertical transverse anteroposterior axis; sagittal plane; xy listing's; yz plane.
fixation axis The line joining the object of regard to the centre of rotation of the eye. Syn. line of fixation.
geometrical axis The line passing through the anterior and posterior poles of the eye. If the refractive surfaces are symmetrical about that axis, it will then coincide with the optical axis.
horizontal axis See transverse axis.
axis notation See standard axis notation.
axis notation, standard The accepted axis notation for cylinders, the same for each eye, whereby the specified axis direction denotes the angle of the cylinder axis with the horizontal measured anticlockwise from 0º to 180º, the front surface of the lens being viewed (British Standard). (Fig. A23) Syn. TABO notation (although the TABO notation specifies the axis direction from 0º to 360º); OCA notation.
optical axis 1. The line joining the optical centres of the refractive surfaces of the eye (a theoretical concept in the eye). A close approximation of this axis is represented by aligning the Purkinje images of a test object (Fig. P14, page 284). 2. The line normal to the surfaces of a lens along which light passes undeviated. See Purkinje-Sanson images.
orbital axis The line from the middle of the orbital opening to the centre of the optic canal. The orbital axes of a normal adult make an angle of approximately 45º with each other. See orbit.
principal axis A line passing through the centre of curvature of a surface and through its vertex.
pupillary axis The line passing through the centre of the entrance pupil of the eye and the pole of the cornea. Syn. pupillary line. See poles of the eyeball.
sagittal axis See anteroposterior axis.
transverse axis A horizontal line passing through the centre of rotation of the eye and lying in Listing's plane. Syn. x-axis. See anteroposterior axis; Listing's plane.
vertical axis A vertical line passing through the centre of rotation of the eye. Syn. z-axis.
visual axis The line joining the object of regard to the foveola and passing through the nodal points which are often considered as coincident, as they are very close to each other. Strictly, this axis is not a single straight line as it consists of two parts: one line connecting the object of regard to the first nodal point and the other line parallel and connecting the second nodal point to the foveola. Syn. visual line. See line of sight.
x-axis See transverse axis.
y-axis See anteroposterior axis.
z-axis See vertical axis.
Fig. A23 Illustration of the standard cylinder axis notationenlarge picture
Fig. A23 Illustration of the standard cylinder axis notation

ax·is

, pl. axes (ak'sis, ak'sēz)
1. [TA] Straight line joining two opposing poles of a spheric body, about which the body may revolve.
2. Central line of the body or any of its parts.
3. [TA] Second cervical vertebra.
4. Vertebral column.
5. Central nervous system.
6. Artery that divides, immediately on its origin, into a number of branches, e.g., celiac axis.

axis (ak´sis),

n 1. a straight line around which a body may rotate.
n 2. the second cervical vertebra, which articulates with the first (atlas) and third cervical vertebrae.
axis, cephalometric,
n See axis, Y.
axis, condylar,
n an imaginary line through the two mandibular condyles around which the mandible may rotate during a part of the opening movement.
axis, condylar, determination,
n the location of the condylar axis by fixing a face-bow rigidly to the mandibular teeth, having the patient open and close the jaws, and recording the most posteriosuperior points of pure rotation with tattoo ink on the outer skin. See also face-bow and hinge-bow.
axis, condyle,
n one of three axes of the jaw condyles: (1) the hinge axis, an intercondyle imaginary line across the face through both condyles; whenever either condyle is chosen to be a rotator, it will display (2) a vertical axis, and (3) a sagittal axis. The hinge axis is a moving center for the opening and closing movements. The vertical axis is the center for the horizontal components of orbital movements. The sagittal axis is the center for the vertical components of orbital movements.
axis, hinge, -orbital plane,
n a craniofacial plane determined by three tattooed points. Two are located with one on each side of the face at the point of exit through the skin in front of the tragus of the imagined extended rearmost mandibular hinge axis. The third point is located on the right side of the nose at the level of the orbital rim just beneath the pupil when the patient is gazing directly forward. This plane corresponds to the anthropologic Frankfort plane.
axis, horizontal,
n See axis, hinge.
axis, long,
n an imaginary line passing longitudinally through the center of a body.
axis, mandibular,
n See axis, condylar.
axis of preparation,
n the path taken by a restoration as it slides on or off the preparation.
axis, opening,
n See axis, condylar.
axis, orbital movements of,
n.pl the movements projected on the axis-orbital plane in gathering the input data for an articulator.
axis, sagittal,
n the imaginary line around which the working condyle rotates in the frontal plane during lateral mandibular movement. The sagittal and vertical axes function concurrently.
axis shift,
n the imprecise term used before the nine different directionalized laterotrusions were discovered and named.
axis, vertical,
n the imaginary line around which the working condyle rotates in the horizontal plane during lateral mandibular movement. The sagittal and vertical axes function concurrently.
axis, Y,
n (cephalometric axis), the angle of a line connecting the sella turcica and the gnathion and related to a horizontal plane. An indicator of downward and forward growth of the mandible.

Axis

genus of deer in family Cervidae.

Axis axis
Axis porcinus

axis

pl. axes [L., Gr.]
1. a line through a center of a body, or about which a structure revolves.
2. the second cervical vertebra.

celiac axis
celiac trunk.
axis cylinder
axon.
dorsoventral axis
one passing from the back to the belly surface of the body.
electrical axis of heart
the resultant of the electromotive forces within the heart at any instant. See also mean electrical axis.
external bulbar axis
the optical axis that connects the anterior and posterior poles of the eyeball. Called also optic axis.
frontal axis
an imaginary line running from right to left through the center of the eyeball.
axis of heart
a line passing through the center of the base of the heart and the apex.
optic axis
see external bulbar axis (above).
orbital axis
a line passing through the apex of the bony orbit and the center of the opening of the orbit.
sagittal axis
an imaginary line extending through the anterior and posterior poles of the eye.
visual axis
an imaginary line passing from the midpoint of the visual field to the fovea centralis.