Anatomy
Summary
The superior vena cava (SVC) serves as the primary vein channeling venous blood from the upper half of the body into the right atrium of the heart. It forms from the convergence of the right and left brachiocephalic veins, which themselves arise from the combination of the internal jugular vein and subclavian vein on each side. Proper placement of central venous catheters (CVCs) requires the tip to terminate within the SVC, although prolonged positioning can cause thrombosis and result in complications such as SVC syndrome, marked by symptoms like venous congestion, swelling, and superficial vein dilation.
The lymphatic system plays a pivotal role in maintaining fluid balance throughout the body. The right lymphatic duct collects lymph from the upper right portion of the body and drains it into the right subclavian vein. Conversely, the thoracic duct drains lymph from the left side and the lower body, depositing it into the left subclavian vein. An injury to the thoracic duct may result in chylothorax, where lymph collects inside the pleural space. Lastly, the azygos vein functions as a vital conduit for venous return, bridging the gap between the SVC and the inferior vena cava (IVC), and offering an alternative route for venous drainage in instances of portal hypertension.
Lesson Outline
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FAQs
The Superior vena cava (SVC) is one of the two main veins bringing deoxygenated blood from the body back to the heart. The SVC is responsible for collecting blood from the upper half of the body, including the head, neck, upper limbs, and upper torso, and channeling it to the right atrium of the heart.
Superior vena cava syndrome, occurs when the SVC is obstructed or compressed. This obstruction can cause venous congestion, manifesting as swelling and discoloration of the upper body, especially the face and arms, and may cause difficulty breathing and other potentially severe symptoms.
The brachiocephalic veins are two large veins that collect blood from the upper limbs and the head and neck via the subclavian and internal jugular veins, respectively. Both brachiocephalic veins merge together to form the superior vena cava, leading the blood towards the heart.
The azygos vein drains venous blood from the esophageal veins, which can become variceal in cases of portal hypertension. This is because the esophageal veins anastomose with the portal venous system via the left gastric vein.
The right lymphatic duct receives lymph drainage from the right arm, the right side of the head and neck, the right hemithorax, and the right upper quadrant of the abdomen. It drains into the right subclavian vein near its confluence with the right internal jugular vein.
