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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
Subarachnoid space ends at
assistant
The correct answer is  The dura and arachnoid along with the subarachnoid space containing CSF extend up to 2nd sacral veebra. Below the lower border of L1 and S2 veebrae, the subarachnoid space contains 40 spinal nerve roots of L2-L5, S1-S5 and Co 1 which constitute the cauda equina. Ref: BD Chaurasia's HUMAN ANATOMY, Volume 3.