A patient with pectus excavatum presents a potential issue in positioning because they have a:

In patients with pectus excavatum, there is a significant indentation in the chest wall caused by a depressed sternum. This deformity can complicate proper positioning during mammography, as the altered contour of the chest may affect the uniformity of the breast tissue placement on the imaging receptor. Proper positioning is crucial to ensure optimal image quality and to capture all necessary breast tissue for evaluation.

Unlike a protruding sternum, which would not create the same challenges in positioning, the depressed sternum can lead to issues such as overlapping tissues or difficulty in adequately immobilizing the breast. A curved spine might influence positioning but is not specifically related to the chest wall deformity characteristic of pectus excavatum. Swollen breast tissue could be a concern in other contexts but does not directly relate to the challenges presented by the chest wall deformity in this patient population. Thus, the presence of a depressed sternum in these patients necessitates careful consideration and possible adjustments in technique to achieve high-quality mammographic images.