This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Anatomy
[{'content': 'Infection of lower lip first reaches blood stream through? \nSelect and explain. \nA. Inferior labile artery, B. Superior labile artery, C. Pterygoid plexus, D. Brachiocephalic vein', 'role': 'user'}, {'content': 'Answer: D \nExplanation: The pathway of spread of intection from lower lip to blood is:\nLip ⇾ Sub mental and submandibular lymph nodes ⇾ deep cervical lymph nodes ⇾ Left and right jugular lymph trunk ⇾ from left jugular trunk thoracic duct & from right at the junction between IJV and subclavian vein\xa0⇾ IJV + subclavian vein = Brachiocephalic vein and two brachiocephalic vein join to form superior vena cava.\nOr directly, we can say infection from any tissue reached the blood stream via venous drainage rather than arterial supply.', 'role': 'assistant'}]