(ak′sĭs )

(ak′sēz″)
pl. axes [L. axis, axle, axis]

1. A real or imaginary line that runs through the center of a body or about which a part revolves.
2. The second cervical vertebra (epistropheus). It bears the odontoid process (dens), about which the atlas rotates.
SYN: SEE: odontoid vertebra

The axis connecting the basion and the gonion.

The axis from the subnasal point to the gonion.

The axis between the two auricular points.

The relationship between the gastrointestinal tract and the central nervous system, specifically between digestive and mental health.

A graphic representation of the main conduction vector of the heart, determined through measurements of direction and amplitude of the complexes in several leads on a 12-lead electrocardiogram. The normal axis is zero to +90°.

The axis between the celiac artery and the abdominal aorta.

SEE: Central nervous system.

SEE: Hinge axis

SEE: Frontal axis.

The hormones and neurotransmitters from the gastrointestinal tract that regulate the secretion of hormones by the pancreas (esp. insulin).

An imaginary line, running from side to side in the frontal plane, about which the anterior to posterior movement occurs.
SYN: SEE: coronal axis

An imaginary line connecting the condyles of the mandible. Movement of the mandible is rotation around this line.
SYN: SEE: condylar axis ; SEE: mandibular axis ; SEE: transverse mandibular axis

SEE: Sagittal plane.

SEE: Hinge axis

SEE: Central nervous system.

A line that connects the anterior and posterior poles of the eye.

An anatomic reference point on the surface of the body, used to approximate the position of the right atrium and pulmonary artery in critical care.

PATIENT CARE
The line is identified by drawing two lines on the supine body: one, in the right midaxillary position, descending from head to foot; and the other, from the anterior to the posterior of the chest, at the level of the fourth intercostal space. The intersection of these two lines is the axis. It is used in critical care to provide a reproducible location for the zeroing in on and leveling of hemodynamic monitoring systems such as pulmonary artery catheters.

In optics, a line that passes through the optical center or nodal point of a lens perpendicular to the surface of the lens.

An imaginary line running anteriorly-posteriorly, about which frontal plane motion occurs.

In imaging studies of anatomical structures (such as the heart), a synonym for transverse axis.
SEE: transverse axis

An axis that connects one side of the body to the other. It is parallel to the ground and perpendicular to both the sagittal and the anteroposterior axes of the body.

SEE: Hinge axis

The line of vision from the object seen through the pupil's center to the macula lutea.