plane (plan) [L. planum, flat surface]
1. A flat or relatively smooth surface.
A flat surface formed by making a cut, imaginary or real, through the body or a part of it. Planes are used as points of reference by which positions of parts of the body are indicated. In the human subject, all planes are based on the body being in an upright anatomical position. See: illustration
; anatomical position
3. A certain stage, as in levels of anesthesia.
4. To smooth a surface or rub away.
Addison plane See: Addison plane
A plane tangent to the alveolar point with most prominent points on lower aspects of condyles of the occipital bone.
A plane that passes through an incisor or canine tooth parallel to the long axis of the tooth and in a labiolingual direction.
A plane that passes through a tooth parallel to the axis and in a mesiodistal direction.
Baer's plane See: Baer's plane
A plane formed by the biting surfaces of the teeth.
The fourth parallel plane of the pelvis.
A vertical plane at right angles to a sagittal plane. It divides the body into anterior and posterior portions. Synonym: frontal plane
An assumed horizontal plane from which craniometric measurements are taken.
Daubenton's plane See: Daubenton's plane
One of two planes through the anterior and posterior principal foci of a dioptric system and perpendicular to the line connecting the two.
Frankfort horizontal plane See: Frankfort horizontal plane
frontal planeCoronal plane.
Hodge's plane See: Hodge, Hugh Lennox
A transverse plane at right angles to the vertical axis of the body.
inclined planes of the pelvis
Anterior and posterior inclined planes of the pelvic cavity, two unequal sections divided by the sciatic spines. In the larger, anterior section, the lateral walls slope toward the symphysis and arch of the pubes; the posterior walls slope in the direction of the sacrum and coccyx. The anterior inclined planes are the declivities over which rotation of the occiput takes place in the mechanism of normal labor.
inclined plane of a tooth
Any sloping surface of the cusp of a tooth.
A horizontal plane passing through the tubercles of the crests of the ilia; lies approx. at the level of the fifth lumbar vertebra.
Listing's plane See: Listing's plane
A vertical plane through the trunk and head dividing the body into right and left halves. Synonym: midsagittal plane See: plane for illus.
midsagittal planeMedian plane.
Morton's plane See: Morton's plane
An imaginary plane extending from the incisal edge of the incisors along the tips of the cusps of the posterior teeth to contact the cranium. Although not a true plane, it represents the mean of the curvature of the occlusal surface.
parallel planes of the pelvis
The planes intersecting the axis of the pelvic canal at right angles. The first plane is that of the superior strait; the second that extending from the middle of the sacral vertebra to the level of the subpubic ligament. The third plane is at the level of the spines of the ischia, and the fourth plane is at the outlet.
planes of the pelvis
Imaginary planes touching the same parts of the pelvic canal on both sides.
plane of refraction
A plane passing through a refracted ray of light and drawn perpendicular to the surface at which refraction takes place.
plane of regard
A plane through the fovea of the eye; fixation point.
A vertical plane through the longitudinal axis of the body or part of the body, dividing it into right and left parts. If it is through the anteroposterior midaxis and divides the body into right and left halves, it is called a median or midsagittal plane.
A horizontal plane passing through the lowest points of the 10th costal cartilages. It lies approx. at the level of the third lumbar vertebra.
A plane that divides the body into a top and bottom portion.
A plane in the concave joint surface that defines the direction of joint mobilization techniques. The plane is perpendicular to a line drawn from the axis of rotation in the convex joint surface to the center of the concave surface. Joint distraction techniques are applied perpendicular to, and gliding techniques parallel to, the treatment plane.
Any body plane perpendicular to a horizontal plane.
A plane passing the visual axis of the eye.