The anteroposterior chest view is an alternative to the PA view when the patient is too unwell to tolerate standing or leaving the bed. The AP view examines the lungs, bony thoracic cavity, mediastinum, and great vessels. This particular projection is often used frequently to aid the diagnosis of acute and chronic conditions in intensive care units and wards. The AP view is of lesser quality than the PA view for many reasons, yet sometimes it is the only imaging available to that patient.