anteriortoposterior

Anteriortoposterior, often written as anteroposterior or AP, refers to a radiographic projection in which the X-ray beam passes from the anterior (front) surface of the body to the posterior (back) surface, with the image receptor typically located behind the patient. This term describes the direction of imaging rather than a specific body region.

In clinical practice, AP is one of several standard radiographic projections used to evaluate bones and soft tissues. It is commonly employed for chest radiographs, as well as imaging of the abdomen, pelvis, and extremities, particularly when a patient is unable to stand or otherwise position for a PA (posterior–anterior) view. The choice between AP and PA can affect image geometry; for example, chest AP images can magnify the cardiac silhouette compared with PA views, potentially influencing measurements and interpretation.

In surgical and orthopedic contexts, the term anteroposterior is used to describe the orientation of implants, surgical approaches, or radiographic views. For instance, an AP view of a joint provides a frontal perspective of structures from anterior to posterior, which can be complemented by lateral or oblique views for a complete assessment.

Synonyms and related terms include anteroposterior projection, AP projection, and, less commonly, anterior–posterior. The opposite projection is posterior–anterior (PA). While AP views are versatile and practical in many settings, radiologists consider patient positioning and potential magnification when interpreting images and choosing the most appropriate projection.