Elongation in radiographic imaging is caused by which of the following?

• A. Collimator angulation too shallow - long image
• B. Collimator angulation too steep - foreshortened image
• C. Patient movement during exposure
• D. Incorrect processing

Answer: (A)

Elongation happens when the projection geometry of the x‑ray beam relative to the anatomy causes the image of a structure to stretch longer than it actually is. If the collimator angulation is too shallow, the beam is directed with less tilt toward the anatomy, so the structure is projected over a longer path on the radiographic image. In other words, the beam and the part aren’t aligned to produce a true-length projection, so components appear elongated.

In contrast, if the angle were steep, the projection would shorten the appearance of the structure—foreshortening. Movement during exposure mainly causes blur, not a lengthening of anatomy, and incorrect processing affects density or contrast rather than the shape.