Abdominal radiograph — supine

Diaphragms to inferior pubic rami

When to use it

Supine AP projection with the patient lying on the table or bed, the beam vertical and centred at about the level of the iliac crests, collimated to include both hemidiaphragms and the inferior pubic rami — the two ends most often clipped, and the two that carry free gas and an obstructed hernia respectively.
Exposed on arrested expiration, which is the opposite of a chest film: expiration reduces diaphragmatic excursion artefact and keeps the abdominal contents in a reproducible position.
A grid and a higher kVp than a limb film are used for the abdomen; in a large patient an under-penetrated film that cannot show the psoas outlines or the properitoneal fat lines should be repeated rather than reported as normal.
A supine film alone cannot show free intraperitoneal gas reliably. Where perforation is the question the additional projection is an ERECT CHEST radiograph, not an erect abdomen, and where the patient cannot sit up a left lateral decubitus abdominal film is the substitute — the projection must be stated on the image.
For enteric tube position the film must include the diaphragm and the upper abdomen in one exposure so the tube can be followed continuously below the carina and past the gastro-oesophageal junction; a film that starts below the diaphragm cannot confirm placement.
Gonad shielding is no longer routinely recommended in current guidance, and the emphasis has moved to tight collimation and correct exposure factors instead.

Insensitive for perforation (an erect chest radiograph or CT is required) and cannot identify the cause or level of obstruction — most obstruction questions ultimately need CT.
Requested for undifferentiated abdominal pain far more often than it can help.

None

Derived from the contrast agent and phases above, not authored here — which is why they cannot drift apart from what the protocol actually does.