Caval opening transmits which structures?

• A. Aorta and thoracic duct
• B. Inferior vena cava and right phrenic nerve
• C. Esophagus and vagus nerves
• D. Pulmonary artery and left phrenic nerve

Answer: (B)

The key idea is which structures pass through the caval opening of the diaphragm. The caval opening, located in the central tendon at about the level of T8, transmits the inferior vena cava and the right phrenic nerve. The IVC brings blood from the lower body to the heart, while the right phrenic nerve provides motor innervation to the diaphragm on the right side. This is why the pair of the inferior vena cava with the right phrenic nerve is the correct match. The other openings have different contents: the aortic hiatus carries the aorta and typically the thoracic duct; the esophageal hiatus carries the esophagus and the vagus nerves; the left phrenic nerve does not pass through the caval opening, and the pulmonary artery remains above the diaphragm, not through a diaphragmatic opening.