Anteroposterior

Anteroposterior (AP) is a directional term used in anatomy and radiology to describe a relationship or projection that runs from the front (anterior) to the back (posterior) of the body or a body part. It is used to indicate orientation along the front-to-back axis and is often paired with other directional terms such as ventral, dorsal, and lateral.

In anatomical description, AP denotes a position or movement from the front toward the back, helping to specify the relative location of structures within a region or organ system. It is one component of standard plane and axis terminology used to communicate precise spatial relationships.

In medical imaging, anteroposterior refers to projections where the x-ray beam travels from anterior to posterior. An AP view is common in chest radiography and other situations where the patient cannot stand or face the image receptor. A related posteroanterior (PA) view has the beam traveling from posterior to anterior and is often preferred for more accurate depiction of heart size because of reduced magnification. AP projections can cause magnification of certain structures, a consideration that radiologists account for during interpretation.

In dental and cephalometric contexts, AP describes sagittal relationships among facial bones and dentition, such as the relative positions of the maxilla and mandible to the cranial base, which are important for assessment and treatment planning.