Plain Abdominal X Ray

PLAIN ABDOMINAL X RAY

Plain Abdominal X Ray

The abdominal cavity extends from the undersurface of the diaphragm above to the pelvic inlet below and is contained by the muscles of the abdominal walls.

To mark the surface anatomy of the viscera, the abdomen is divided into nine regions by two transverse planes and two parasagittal (or vertical) planes.

Plain Abdominal X Ray

The upper transverse plane, called the transpyloric plane, is midway between the suprasternal notch and the symphysis pubis, approximately midway between the upper border of the xiphisternum and the umbilicus.

Plain Abdominal X Ray

Posteriorly, it passes through the body of the first lumbar vertebra near its lower border; anteriorly, it passes through the tips of the right and left ninth costal cartilages.

Plain Abdominal X Ray

The lower transverse plane, called the transtubercular plane, is at the level of the tubercles of the iliac crest anteriorly and near the upper border of the fifth lumbar vertebra posteriorly. The two parasagittal planes are at right-angles to the two transverse planes.

Plain Abdominal X Ray

They run vertically, passing through a point midway between the anterior superior iliac spine and the symphysis pubis on each side.

Individuals have been classified, according to body build, into four types:

• hypersthenic,
• sthenic,
• hyposthenic and
• asthenic.

The shape and position of organs tend to follow a particular pattern typifying each type.

Plain Abdominal X Ray

Hypersthenic – massively built. The dome of the diaphragm is high and the lower costal margin is at a high level with a wide angle, resulting in the widest part of the abdomen being its upper part.

Plain Abdominal X Ray

The stomach and transverse colon are in the upper part of the abdomen. The fundus of the gallbladder is pushed upwards so that the gallbladder lies horizontally in the abdomen well away from the midline.

Plain Abdominal X Ray

Asthenic – thin and slender. The elongated narrow thorax with a narrow costal angle is associated with a low position of the dome of the diaphragm.

The abdominal cavity is shallow, being widest in its lowest region.

The pylorus of the stomach is low and the long stomach may reach well below the iliac crests, while the transverse colon can loop down into the pelvic cavity.

The gallbladder lies vertically close to the midline, with the fundus below the level of the iliac crests

Plain Abdominal X Ray

Between these two extremes of body build are the sthenic (tending towards hypersthenic, but not as broad in proportion to height) and the hyposthenic (tending towards asthenic, but not as thin and slender).

INDICATIONS

• obstruction of the bowel;
• perforation;
• renal pathology;
• acute abdomen (with no clear clinical diagnosis);
• foreign body localization
• toxic megacolon;
• aortic aneurysm;

Plain Abdominal X Ray

• prior to the introduction of a contrast medium, e.g. intravenous urography (IVU) to demonstrate the presence of radiopaque renal or gallstones and to assess the adequacy of bowel preparation;
• to detect calcification or abnormal gas collections, e.g. abscess;
• alimentary studies using barium preparations.

Typical imaging protocols