Anatomy and Radiography of the Abdomen: Muscles, Organs, and Imaging Techniques

The two large muscles found in the posterior abdomen adjacent to the lumbar vertebra that are usually visible on an AP radiograph are called the...

Psoas major

The medical prefix for stomach is...

Gastro-

What are the three parts of the small intestine?

Duodenum, Jejunum, Ileum

Which portion of the small intestine is considered to be the longest?

Ileum

The large intestine begins in which quadrant and with what saclike area?

Right lower quadrant; Cecum

The sigmoid colon is located between which two structures of the large intestine?

Descending colon and rectum

Which organ is considered part of the lymphatic system?

Spleen

What are the three accessory digestive organs?

Liver, Gallbladder, Pancreas

The pancreas is located _______ to the stomach.

Posteriorly

True/False: The correct term for the radiographic study of the entire urinary system is the intravenous pyelogram (IVP).

False (The correct term is Intravenous Urogram [IVU])

Why is the right kidney found in a more inferior position than the left kidney?

Because of the presence of the large liver on the right side.

Which endocrine glands are superomedial to each kidney?

Suprarenal (adrenal) glands

The double-walled membrane that lines the abdominopelvic cavity is called the...

Peritoneum

The organs located posteriorly to, or behind, the serous membrane lining of the abdominopelvic cavity are referred to as...

Retroperitoneal

Which structure helps stabilize and support the small intestine?

Mesentery

Which structure is a double fold of peritoneum that connects the transverse colon to the greater curvature of the stomach?

Greater omentum

Peritoneal Location: Liver

Intraperitoneum

Peritoneal Location: Urinary bladder

Infraperitoneum

Peritoneal Location: Kidneys

Retroperitoneum

Peritoneal Location: Spleen

Intraperitoneum

Peritoneal Location: Ovaries

Infraperitoneum

Peritoneal Location: Duodenum

Retroperitoneum

Peritoneal Location: Transverse colon

Intraperitoneum

Peritoneal Location: Testes

Infraperitoneum

Peritoneal Location: Adrenal glands

Retroperitoneum

Peritoneal Location: Stomach

Intraperitoneum

Peritoneal Location: Pancreas

Retroperitoneum

Peritoneal Location: Ascending and descending colon

Retroperitoneum

Abdominal Quadrant: Liver

RUQ

Abdominal Quadrant: Spleen

LUQ

Abdominal Quadrant: Sigmoid colon

LLQ

Abdominal Quadrant: Left colic flexure

LUQ

Abdominal Quadrant: Stomach

LUQ

Abdominal Quadrant: Appendix

RLQ

Abdominal Quadrant: Two-thirds of jejunum

LUQ

What is the correct name for the abdominal region found directly in the middle of the abdomen?

Umbilical

Which abdominal region contains the rectum?

Pubic

What are the two causes of voluntary motion?

Patient breathing and patient movement during exposure

Voluntary motion can best be prevented by...

Careful breathing instructions to the patient

What is the primary cause for involuntary motion in the abdomen?

Peristaltic action of the bowel

What is the best mechanism to control involuntary motion?

Use the shortest exposure time possible

True/False: Because the liver margin is visible in the RUQ, it is not necessary to place an anatomic side marker on the cassette before exposure.

False

True/False: For an adult abdomen, a collimation margin must be visible on all four sides of the radiograph.

False

Gonadal shielding should not be used during abdomen radiography if...

It obscures essential anatomy, interferes with the AEC system, or goes against local policy.

Gonadal shielding may be impossible for studies of the lower abdominopelvic region for which gender?

Females

Gonadal shielding for females involves placing the top of the shield at the level of the ______ and the bottom at the ______.

ASIS; Symphysis pubis

Which exposure considerations would be most ideal for an AP abdomen of an average-sized adult using a digital radiographic system?

70-85 kVp, grid, 40-inch (100-cm) SID

Which technical considerations are essential when performing abdomen studies on a young pediatric patient?

Short exposure times, high-speed image receptor, and reduced kVp and mAs

True/False: A radiolucent pad should be placed underneath geriatric patients for added comfort.

True

True/False: The umbilicus is a reliable, alternative landmark to use for the bariatric patient.

False

True/False: The image receptor should be placed in portrait alignment for an abdomen study on a bariatric patient.

False

With the use of iodinated contrast media, which modality is able to distinguish between a simple cyst and a tumor of the liver?

CT (Computed Tomography)

The preferred imaging modality for examining the gallbladder quickly is...

Ultrasound

Which modality is recommended to evaluate patients with acute appendicitis?

CT (or Ultrasound)

Pathology: Free air or gas in the peritoneal cavity

Pneumoperitoneum

Pathology: Inflammatory condition of the colon

Ulcerative colitis

Pathology: Telescoping of a section of bowel into another loop of bowel

Intussusception

Pathology: Abnormal accumulation of fluid in the peritoneal cavity

Ascites

Pathology: Bowel obstruction caused by a lack of intestinal peristalsis

Adynamic (paralytic) ileus

Pathology: A twisting of a loop of bowel creating an obstruction

Volvulus

Pathology: Chronic inflammation of the intestinal wall that may result in bowel obstruction

Crohn disease

Appearance: Distended loops of air-filled small intestine

Crohn disease

Appearance: Air-filled "coiled spring" appearance

Intussusception

Appearance: General abdominal haziness

Ascites

Appearance: Thin crest-shaped radiolucency underneath diaphragm

Pneumoperitoneum

Appearance: Deep air-filled mucosal protrusions of colon wall

Ulcerative colitis

Appearance: Large amount of air trapped in sigmoid colon with a tapered narrowing at the site of obstruction

Volvulus

The central ray (CR) is centered to the level of the _______ for a supine AP projection of the abdomen.

Iliac crest

Exposure for an AP projection of the abdomen should be taken on _______.

Expiration

Rotation can be determined on a KUB radiograph by the loss of the symmetric appearance of...

Iliac wings, obturator foramina, ischial spines, and outer rib margins

Which body habitus might require two landscape-aligned image receptors to be taken so the entire abdomen is included?

Hypersthenic

True/False: A tall asthenic patient may require two 14 x 17-inch image receptors placed portrait so the entire abdomen is included.

True

True/False: For a KUB, it is accepted practice to indicate the side of the body during postprocessing after the exposure has been completed.

False (Patient may have situs inversus)

Why is it recommended to take abdominal radiographs at the end of patient expiration?

To increase the room for expansion of the abdominal organs within the abdominal cavity

Which abdominal structure is not visible on a properly exposed KUB?

Pancreas

Why may the PA projection of a KUB generally be less desirable than the AP projection?

Increased object-image receptor distance (OID) of the kidneys

Which decubitus position of the abdomen best demonstrates intraperitoneal air in the abdomen?

Left lateral decubitus (free air best visualized in the upper right abdomen in the area of the liver)

Why should a patient be placed in the decubitus position for a minimum of 5 minutes before exposure?

To allow intra-abdominal air to rise or abnormal fluids to accumulate

Which decubitus position best demonstrates possible aneurysms, calcifications of the aorta, or umbilical hernias?

Dorsal decubitus

Which projection best demonstrates a possible aortic aneurysm in the prevertebral region of the abdomen?

Lateral position

List the projections commonly performed for an acute abdominal series (3-way series).

AP supine, AP erect (or lateral decubitus), and PA erect chest

Which projection of the acute abdominal series best demonstrates free air under the diaphragm?

PA erect chest

Which positioning routine should be used for an acute abdominal series if the patient is too ill to stand?

Two-projection series: AP supine abdomen and left lateral decubitus

Which projection of the abdomen/chest series requires a high kVp setting of 110-125?

PA erect chest for free air under the diaphragm

To ensure the diaphragm is included on an erect abdomen projection, the CR should be at what level?

2 inches (5 cm) above the iliac crest (places top of IR at the axilla)

What is the recommended overlap when using two landscape-placed image receptors for an AP projection of a bariatric patient?

1-2 inches (3-5 cm)

What scale of contrast is recommended for visualization of the abdominal structures on an abdominal x-ray?

Long scale (low contrast)

True/False: The patient best controls peristalsis by holding his or her breath during exposure.

False (Short exposure time best controls it)

Situation: ICU patient with suspected intra-abdominal bleeding who cannot stand or travel. What portable routine is used?

Bedside portable left lateral decubitus projection

Situation: A patient with a history of ascites comes to radiology. Which position best demonstrates this condition?

Erect AP abdomen (best demonstrates fluid levels)

Situation: A KUB shows the gonadal shield is superior to the upper margin of the symphysis pubis, cutting off kidney stone tracking. What is the next step?

Repeat the exposure with the gonadal shielding positioned below the symphysis pubis

Situation: A bariatric KUB shows the upper abdomen/kidneys are cut off. What is the next step?

Repeat using two landscape-aligned 14 x 17-inch image receptors to ensure full coverage

Situation: ER patient has a large distended abdomen from an ileus. Average factors are 76 kVp, 30 mAs. How should exposure factors change?

Decrease the mAs (trapped air is easier to penetrate; avoids overexposure)

Situation: A child may have swallowed a coin. Which routine best identifies the exact location of the coin?

KUB and lateral abdomen (two projections 90 degrees opposite)