A central venous catheter tip placed in the superior vena cava is withdrawn so that it lies just proximal to the SVC. In which vessel is the catheter tip now located?

A central venous catheter tip placed in the superior vena cava is withdrawn so that it lies just proximal to the SVC. In which vessel is the catheter tip now located?

• A. Subclavian vein
• B. Brachiocephalic vein
• C. Cephalic vein
• D. Internal jugular vein

Answer: (B)

The main idea is how central venous catheter tips sit in central veins relative to the SVC. If a tip initially in the SVC is withdrawn to lie just before (proximal to) the SVC, it will be in the brachiocephalic vein—the vessel that contributes to forming the SVC by joining with its counterpart. In other words, the tip sits in the brachiocephalic vein, just upstream from where the two brachiocephalic veins unite to form the SVC. The other vessels are less likely locations for a tip in this position: the subclavian vein is a lateral continuation of the axillary vein and not the segment immediately before the SVC; the internal jugular vein drains the neck and brain and would typically be higher up; the cephalic vein is a superficial arm vein far from the central venous system.

The main idea is how central venous catheter tips sit in central veins relative to the SVC. If a tip initially in the SVC is withdrawn to lie just before (proximal to) the SVC, it will be in the brachiocephalic vein—the vessel that contributes to forming the SVC by joining with its counterpart. In other words, the tip sits in the brachiocephalic vein, just upstream from where the two brachiocephalic veins unite to form the SVC.

The other vessels are less likely locations for a tip in this position: the subclavian vein is a lateral continuation of the axillary vein and not the segment immediately before the SVC; the internal jugular vein drains the neck and brain and would typically be higher up; the cephalic vein is a superficial arm vein far from the central venous system.