Anatomy Radiology of the Thorax TBL

What is the abdominal aorta?

Continuation of the thoracic aorta after passing through the aortic hiatus of the diaphragm at approximately the T12 vertebral level. Runs inferiorly along the anterior surfaces of the lumbar vertebral bodies. Lies slightly to the left of midline. Is bracketed on either side by the right and left crura of the diaphragm in the upper abdomen. Appears more round and rigid than the inferior vena cava on CT due to thicker arterial walls.

What is the right crus of the diaphragm?

Portion of the diaphragm that passes on the right side of the abdominal aorta in the upper abdomen. Brackets the right side of the abdominal aorta adjacent to the lumbar vertebral bodies.

What is the left crus of the diaphragm?

Portion of the diaphragm that passes on the left side of the abdominal aorta in the upper abdomen. Brackets the left side of the abdominal aorta adjacent to the lumbar vertebral bodies.

What is the psoas major?

Paired muscles located on either side of the lumbar vertebral bodies along the posterior abdominal wall. Visible in cross section lateral to the vertebral bodies and medial to the kidneys.

What is the esophagus in abdominal imaging?

Structure that runs anterior to the interval between the thoracic aorta and azygos vein in the thorax and crosses anterior to the aorta at lower levels. Passes through the diaphragm and immediately feeds into the stomach. Located anterior and slightly to the left of the thoracic and abdominal aorta.

What is the stomach?

Sac-like organ primarily located in the left upper quadrant of the abdomen. Appears different from solid water-density organs like the liver and spleen. May contain air and oral contrast if administered. Has an oblique orientation with the superior portion being more posterior and lateral to the left and the inferior portion being more anterior and medial. Receives the esophagus from above.

What is the inferior vena cava?

Large vein that runs along the right side of the abdominal aorta. Has weaker walls than an artery of similar size and may appear compressed by adjacent organs on CT. In the upper abdomen it is embedded in the posterior surface of the liver and may appear to disappear into the liver if no contrast is administered. Drains into the right atrium immediately superior to the diaphragm.

What is the liver?

Large water-density organ filling the right upper quadrant of the abdomen and extending into the left upper quadrant. The inferior vena cava is embedded in its posterior surface.

What is the spleen?

Water-density structure located in the left upper quadrant of the abdomen. Similar in appearance to the liver but smaller and on the left side. Lies posterior and lateral to the stomach and anterior and lateral to the left kidney.

What is the gallbladder?

Small structure tucked up against the inferior surface of the liver. Contains bile which is less radiodense than liver tissue and therefore appears darker gray on CT scans.

What is the right kidney?

Retroperitoneal organ that lies against the posterior abdominal wall lateral to the vertebral bodies and psoas major. The hilum faces anteromedially. The right kidney tends to be slightly lower than the left kidney.

What is the left kidney?

Retroperitoneal organ that lies against the posterior abdominal wall lateral to the vertebral bodies and psoas major. The hilum faces anteromedially. The left kidney tends to be slightly higher than the right kidney.

What is the right suprarenal gland?

Small V-shaped or Y-shaped structure superior and anteromedial to the right kidney. Located posterior to the inferior vena cava.

What is the left suprarenal gland?

Small V-shaped or Y-shaped structure superior and anteromedial to the left kidney.

What is the pancreas?

Centrally positioned water-density structure in the upper abdomen. Margins may appear fluffy or cloud-like and it may be difficult to differentiate from adjacent organs. Lies posterior to the stomach and anterior to the left kidney. The head is cradled by the duodenum and the tail is related to the spleen.

What is the 2nd part of the duodenum?

Vertically oriented portion of the duodenum. Located to the right and posterior of the head of the pancreas. Lies anterior to the hilum of the right kidney.

What is the 3rd part of the duodenum?

Horizontally oriented portion of the duodenum. Passes from the left of the second part of the duodenum. Lies immediately inferior to the head of the pancreas and passes anterior to the inferior vena cava and abdominal aorta.

What is the ascending colon?

Vertically oriented portion of the large intestine running along the posterior abdominal wall on the right side. May contain air and or fecal material and demonstrates characteristic haustra.

What is the descending colon?

Vertically oriented portion of the large intestine running along the posterior abdominal wall on the left side. May contain air and or fecal material and demonstrates characteristic haustra.

What is the celiac trunk?

First anteriorly directed branch of the abdominal aorta. Typically arises at the T12 vertebral level. Branches from the anterior surface of the abdominal aorta.

What is the splenic artery?

Left-directed branch of the celiac trunk. Runs posterior and superior to the upper margin of the pancreas toward the spleen. Follows a sinusoidal course and may appear as disconnected circles or ovals on axial CT.

What is the common hepatic artery?

Right-directed branch of the celiac trunk. Diverges to the right from the splenic artery and supplies the liver.

What is the hepatic portal vein?

Large vein formed by the joining of the splenic vein from the left and the superior mesenteric vein from below. Forms posterior to the neck of the pancreas. Runs upward and laterally to the right toward the liver.

What is the splenic vein?

Vein that runs along the posterior surface of the body of the pancreas from the spleen. Lies inferior to the splenic artery. Joins the superior mesenteric vein to form the hepatic portal vein.

What is the left renal vein?

Vein that drains the left kidney into the inferior vena cava. Longer than the right renal vein. Passes anterior to the abdominal aorta and anterior to the left renal artery.

What is the right renal vein?

Vein that drains the right kidney into the inferior vena cava. Shorter than the left renal vein. Lies anterior to the right renal artery.

What is the left renal artery?

Laterally directed branch of the abdominal aorta supplying the left kidney. Passes posterior to the left renal vein.

What is the right renal artery?

Laterally directed branch of the abdominal aorta supplying the right kidney. Longer than the left renal artery. Passes posterior to the inferior vena cava and posterior to the right renal vein.

What is the superior mesenteric artery?

Second anteriorly directed branch of the abdominal aorta. Typically arises at the L1 vertebral level posterior to the pancreas. Descends inferiorly and passes anterior to the left renal vein and the third part of the duodenum.

What is the superior mesenteric vein?

Vein that runs along the right side of the superior mesenteric artery. Passes anterior to the uncinate process of the pancreas. Ascends posterior to the neck of the pancreas and joins the splenic vein to form the hepatic portal vein.

What is the uncinate process of the pancreas?

Leftward projection of the inferior-most part of the head of the pancreas. Lies posterior to the superior mesenteric vein.

What is the inferior mesenteric artery?

Anteriorly and leftward directed branch of the abdominal aorta. Typically arises at the L3 vertebral level. Origin is posterior or inferior to the third part of the duodenum.

What is the inferior mesenteric vein?

Vein that ascends upward to the left of the inferior mesenteric artery. Usually joins the splenic vein