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
All of the following are present beneath floor of 4th ventricle except
assistant
The correct answer is  Facial colliculus, a swelling in floor of 4th ventricle is formed by facial nerve looping around abducens nucleus. So facial nucleus doesn’t form the floor of 4th ventricle.