Elongation occurs when the X-ray beam is angled along the long axis of a part.

Elongation occurs when the X-ray beam is angled along the long axis of a part.

• A. Elongation
• B. Magnification
• C. Minification
• D. Foreshortening

Answer: (A)

Elongation is a projection effect that occurs when the X-ray beam is angled along the long axis of a part. Angling the beam obliquely causes the image of that long dimension to be stretched on the image receptor, so the structure appears longer than its true size. This happens even though the actual anatomy hasn’t changed, because the projection of the long axis onto the film increases with the oblique angle. In contrast, foreshortening would make a structure appear shorter if the beam is angled across or toward the short axis, and magnification depends on the distance between the part and the receptor rather than the direction of the beam along the axis.

Elongation is a projection effect that occurs when the X-ray beam is angled along the long axis of a part. Angling the beam obliquely causes the image of that long dimension to be stretched on the image receptor, so the structure appears longer than its true size. This happens even though the actual anatomy hasn’t changed, because the projection of the long axis onto the film increases with the oblique angle. In contrast, foreshortening would make a structure appear shorter if the beam is angled across or toward the short axis, and magnification depends on the distance between the part and the receptor rather than the direction of the beam along the axis.