<Li> ^ Jump up to: Uncommon use . </Li> <Li> Jump up ^ Equivalent to one - half of the left - right axis . </Li> <P> To begin with, distinct, polar - opposite ends of the organism are chosen . By definition, each pair of opposite points defines an axis . In a bilaterally symmetrical organism, there are 6 polar opposite points, giving three axes that intersect at right angles--the x, y, and z axes familiar from three - dimensional geometry . </P> <P> The terms "intermediate", "ipsilateral", "contralateral", "superficial", and "deep", while indicating directions, are relative terms and thus do not properly define fixed anatomical axes . Also, while the "rostrocaudal" and anteroposterior directionality are equivalent in a significant portion of the human body, they are different directions in other parts of the body . </P>

When describing the human an alternative anatomical term for anterior is