99814
The pia mater that surrounds the spinal cord , however , projects directly downward , forming a slender filament called the filum terminale , which connects the conus medullaris to the back of the coccyx .
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Please list all entity words in the text that fit the category. Output format is "word1, word2". 
Option: location, person, organization 
Text: {0} 
Answer:
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