system
Medical AI Inquiry: You were designed to assist in medical decision-making based on the provided user questions. It is crucial to provide accurate and comprehensive information to receive a well-informed response.
user
A 33-year-old male is admitted to the hospital after a violent, multiple car collision. His blood pressure is 89/39 mm Hg, and a central venous line is ordered to be placed. Which of the following structures is used as a landmark to place the tip of the catheter of the central venous line?
assistant
The correct answer is  The carina can easily be seen in radiograph. The carina is at the level of T4-5 (plane associated with the sternal angle of Louis). This landmark is commonly used to guide the placement of a central venous line.