Which nerves traverse the diaphragm through the crura?

• A. Vagus nerves
• B. Greater, lesser and least splanchnic nerves
• C. Phrenic nerves
• D. Pelvic splanchnic nerves

Answer: (B)

The nerves that pass through the diaphragmatic crura are the greater, lesser, and least splanchnic nerves. The crura form part of the aortic hiatus, which is the opening through which these thoracic splanchnic nerves enter the abdomen. They carry preganglionic sympathetic fibers (and visceral afferents) to prevertebral ganglia: the greater splanchnic goes to the celiac ganglion, the lesser to the superior mesenteric ganglia, and the least to neighboring renal or aorticorenal ganglia.

In contrast, the vagus nerves travel with the esophagus through the esophageal hiatus, not the crura; the phrenic nerves descend to innervate the diaphragm itself and pass through the muscular portion or central tendon rather than via the crura; pelvic splanchnic nerves (S2–S4) go to the pelvic viscera and do not traverse the diaphragmatic crura.