sagittal axis

sagittal axis

n.

1. The optic axis.

2. The line around which the working condyle rotates in the frontal plane during mandibular movement.

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sagittal axis,

a hypothetical line through the mandibular condyle that serves as an axis for rotation of the mandible.

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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.

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sagittal (saj´tl),

adj shaped like or resembling an arrow; straight; situated in the direction of the sagittal suture. Said of an anteroposterior plane or section parallel to the long axis of the body.

sagittal axis,

n a hypothetical line through the mandibular condyle that serves as an axis for rotation movements of the mandible.

sagittal plane,

n See plane, sagittal.

sagittal splitting of mandible,

n an intraoral osteotomy of the ascending ramus and posterior body of the mandible in the sagittal plane for the correction of prognathism, retrognathism, or apertognathia. An alternative procedure confines the split to the body of the mandible.

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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.

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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.