From the Research
The superior vena cava (SVC) is primarily formed by the confluence of the right and left brachiocephalic veins, which are themselves formed by the union of the internal jugular vein and subclavian vein on each side. The SVC also receives blood from other tributaries, including the azygos vein, internal thoracic veins, vertebral veins, inferior thyroid veins, and small mediastinal and pericardial veins 1. Understanding the anatomy of the SVC and its tributaries is crucial for diagnosing and managing conditions such as SVC syndrome, which can cause significant morbidity and mortality if left untreated.
Principal Contributors to the SVC
- Right brachiocephalic vein
- Left brachiocephalic vein
- Azygos vein
- Internal thoracic veins
- Vertebral veins
- Inferior thyroid veins
- Small mediastinal and pericardial veins
The brachiocephalic veins are formed by the union of the internal jugular vein and subclavian vein on each side, and they play a critical role in draining deoxygenated blood from the upper half of the body into the SVC 1. The azygos vein, which joins the SVC posteriorly, also contributes to the drainage of blood from the thoracic cavity.
Clinical Significance
Understanding the venous drainage pattern of the SVC is essential for clinicians to diagnose and manage conditions such as SVC syndrome, which can cause facial and upper extremity swelling due to impaired venous return from these areas. The SVC is responsible for returning deoxygenated blood from the upper half of the body to the right atrium of the heart, and any obstruction or disruption to this vessel can have significant consequences for patient morbidity and mortality 2.