Crosssectioning

Cross-sectioning is the process of removing material to expose a cross-sectional plane of a material or specimen. The resulting slice reveals internal features that are not visible from the exterior and supports analysis of structure, composition, or function. The practice is widespread across biology, medicine, geology, materials science, and engineering, and each field has its preferred planes, thicknesses, and preparation methods.

In histology and pathology, cross-sectioning involves embedding tissue in paraffin or resin, cutting very thin sections with a microtome or cryostat, mounting on slides, and staining for microscopic examination. Typical thicknesses range from about 3 to 6 micrometers for paraffin sections and somewhat thicker for resin-embedded specimens; frozen sections are often 5 to 20 micrometers.

In materials science and geology, cross-sections are produced by saw-cutting, mounting, and grinding or polishing to produce a flat face, then examined by light microscopy or electron microscopy. Rock thin sections are usually around 30 micrometers thick.

In imaging, cross-sectional data are generated by computed tomography (CT) or magnetic resonance imaging (MRI), providing successive slices through a body or object for three-dimensional reconstruction.

Artifacts such as chatter, compression, knife marks, tears, or delamination can occur during sectioning and may require adjustments in embedding, cutting speed, blade choice, or mounting procedures.