Compressed or wrinkled sections are most likely caused by which of the following?

• A. The wrong blade tilt
• B. Too cold water bath
• C. Too fast a microtomy feed
• D. Overfixation

Answer: (A)

When the knife edge interacts with the tissue, a clean, shearing cut relies on proper blade geometry. If the blade is tilted incorrectly, the edge engages the tissue at an improper angle, causing uneven pressure across the section. Instead of a smooth shear, the tissue gets pressed and folded, producing compressed or wrinkled sections. The fix is to adjust the blade tilt so the edge cuts perpendicular (or with the correct clearance) to the block face and to ensure the blade is sharp and properly aligned. Other factors like a too cold water bath, too fast a microtomy feed, or overfixation can cause other artifacts, but the wrinkle/compression pattern is most directly tied to improper blade tilt.