"CLO 11 Summarize the relationship of factors that control and affect distortion."

Distortion occurs when there is misrepresentation of either size or shape of the anatomic part.

OID (object-to-image) is a factor of distortion. When an object is lifted off of the surface, it causes the part to look magnified (size distortion) on the radiograph. 

SID (source-to-image) decreases magnification when it increases. 

Foreshortening and elongation are caused by misalignment of the part to the image receptor, inaccurate central ray alignment of the tube, or the image receptor alignment itself. 

Fauber, T. L. (2017). Radiographic imaging & exposure. St. Louis, MO: Elsevier.