Master Pathways through the Diaphragm with Picmonic for Medicine

The caval opening passes through the central tendon of the diaphragm. It is located at the level of T8. It contains the inferior vena cava.

The inferior vena cava (IVC) passes through the caval opening. The IVC is a large vein which carries deoxygenated blood from the abdomen and lower limbs to the right atrium of the heart. Occlusion or trauma of the IVC is a life threatening situation, as it may lead to thromboembolism or exsanguination.

The esophageal opening, also known as the esophageal hiatus, is situated in the posterior part of the diaphragm. It is located at the level of T10. It contains the esophagus, vagus nerve, and esophageal branches of the left gastric vessels.

The esophagus passes through the esophageal opening. The esophagus connects the mouth to the stomach and pushes food boluses downwards via peristalsis. The top of the esophagus has striated muscle under voluntary control for swallowing. However, the lower two thirds of the esophagus is involuntary smooth muscle controlled by the autonomic nervous system.

The vagus nerve passes through the esophageal opening. The vagus nerve, also known as CN X, is a motor, sensory and visceral nerve with several functions, such as heart rate regulation, respiratory drive regulation, palate elevation, swallowing, and talking.

Esophageal branches of the left gastric vessels pass through the esophageal opening. These are vessels that supply the esophagus with blood.

The aortic opening, also known as the aortic hiatus, is situated slightly posterior to the diaphragm. It is located at the level of T12. It permits the passage of the aorta, thoracic duct and azygos vein.

The descending aorta passes through the aortic opening. The aorta is a large artery that originates from the left ventricle of the heart and extends down the abdomen, where it splits into the common iliac arteries. It distributes oxygenated blood to the body through the systemic circulation.

The thoracic duct passes through the aortic opening. The thoracic duct is the main lymphatic channel for the return of chyle to the venous system.

The azygos vein passes through the aortic opening. The azygos vein is a unilateral vessel that ascends the thorax on the right side of the vertebral column. It is part of the azygos venous system.