os trapezoideum vs trapezium

os trapezoideum

noun
  • Synonym of trapezoid bone 

trapezium

noun
  • The trapezium bone of the wrist. 

  • A region on the ventral side of the brain, either just back of the pons Varolii, or, as in man, covered by the posterior extension of its transverse fibers. 

  • A quadrilateral with two sides parallel and two sides non-parallel. 

  • A quadrilateral with two sides parallel. 

How often have the words os trapezoideum and trapezium occurred in a corpus of books? (source: Google Ngram Viewer )