The diaphragm has several openings or apertures through which various structures pass between the thoracic and abdominal cavities. Here are the main apertures in the diaphragm, along with their levels and the structures that pass through each:
1. Aortic Hiatus:
- Level: T12 (12th thoracic vertebra)
- Structures Passing Through:
- Descending (thoracic) aorta
2. Esophageal Hiatus:
- Level: T10 (10th thoracic vertebra)
- Structures Passing Through:
- Esophagus
- Vagus nerves
- Esophageal branches of the left gastric vessels
3. Caval Opening (Inferior Vena Cava Opening):
- Level: T8 (8th thoracic vertebra)
- Structures Passing Through:
- Inferior vena cava (IVC)
- Right phrenic nerve
Additional Notes:
- These openings are located at different levels along the vertebral column, and their levels correspond to the thoracic vertebrae.
- The aortic hiatus is the most superior, followed by the esophageal hiatus, and then the caval opening.
Clinical Correlations:
- Hiatal Hernia:
- A hiatal hernia occurs when a portion of the stomach protrudes through the esophageal hiatus into the thoracic cavity. This can lead to gastroesophageal reflux and other symptoms.
- Aortic Aneurysm:
- Conditions such as an aortic aneurysm may involve dilation of the descending aorta, potentially affecting the aortic hiatus.
- Inferior Vena Cava (IVC) Obstruction:
- Obstruction or compression of the IVC can occur, affecting venous return from the lower body.
- Phrenic Nerve Injury:
- Damage to the right phrenic nerve, which passes through the caval opening, can lead to paralysis or weakness of the right hemidiaphragm.
Understanding the locations and structures passing through these diaphragmatic apertures is crucial for clinicians in fields such as surgery, radiology, and gastroenterology. It aids in the diagnosis and management of conditions related to the diaphragm and structures passing through it.