Left superior vena cava with left azygos vein

Area of Science:

• Anatomy
• Embryology
• Cardiovascular System

Background:

• The superior vena cava (SVC) is a major vein that returns deoxygenated blood from the upper body to the heart.
• Variations in SVC development, such as a persistent left SVC, are uncommon but documented in anatomical literature.

Observation:

• A cadaver dissection revealed a complete absence of the right superior vena cava.
• A left superior vena cava was identified, originating from the confluence of the brachiocephalic veins and draining into the coronary sinus.
• A left azygos vein, collecting blood from intercostal veins, was observed to drain into the left superior vena cava.

Findings:

• The developmental mechanism suggests persistence of the left anterior and common cardinal veins with degeneration of the right counterparts for the left SVC.
• The left azygos vein's development is attributed to the persistence of the left posterior cardinal vein.

Implications:

• This case provides valuable data for understanding venous system embryogenesis and variations.
• Awareness of such anatomical variations is crucial for accurate interpretation of medical imaging and surgical planning in the thoracic region.