Middenlijnen

Middenlijnen is a Dutch term used to describe reference lines that mark a central axis or symmetry in different disciplines. They act as anchors for measurement, alignment, and planning, and can be physical lines drawn on diagrams or conceptual planes.

In geometry, middenlijnen refer to lines that bisect figures or connect midpoints of sides. A common example is the midline (midsegment) of a triangle: the line segment joining the midpoints of two sides. In circles, the central axis through the center is the diameter, often considered a primary middenlijn in Dutch geometry.

In anatomy and medicine, the term denotes the body's midsagittal axis—the median line that divides the body into left and right halves. This reference line is used in clinical assessment and imaging to evaluate symmetry and anatomical alignment.

In dentistry, the dental midline is the line between the upper central incisors. A corresponding facial midline is used to assess esthetics and occlusion; deviations can indicate misalignment of teeth or jaws.

In other fields such as cartography and engineering, middenlijnen appear as centerlines or axes on plans and schematics, aligning structures, roads, or waterways with the overall layout.

The concept of middenlijnen emphasizes centrality and symmetry, providing a consistent reference across domains. See also: symmetry axis, sagittal plane, midline, midsegment.