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
The vein formed by union of posterior division of retromandibular vein and posterior auricular vein is
assistant
The correct answer is  External jugular vein is formed by posterior auricular vein and posterior division of retromandibular vein.