The lines in the section shown are most likely due to which artifact?

• A. Defects in the blade edge
• B. Tissue folding
• C. Air bubbles
• D. Staining precipitate

Answer: (A)

Defects in the blade edge cause lines in sections. When the microtome knife has nicks, burrs, or is dull, the edge catches or drags on the tissue as it cuts. This creates fine, parallel striations or chatter marks that run across the entire section, reflecting the direction of the knife edge. These linear lines are a mechanical artifact from the cutting process and are not related to how the tissue was mounted or stained.

Tissue folding would show irregular folds or overlapping tissue, not clean parallel lines. Air bubbles appear as holes or round pockets within the section. Staining precipitate shows up as particulate deposits or crystals within the tissue. To fix blade-edge lines, inspect and sharpen or replace the blade, verify microtome alignment and settings, and trim the block to ensure a clean cut.