nidus avis

vĭs]
n.
  1. A deep depression on each side of the inferior surface of the cerebellum in which the cerebellar tonsil rests.nidus hirundinus
The American Heritage® Stedman's Medical Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Published by Houghton Mifflin Company.

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