"Since the beginning of the twentieth century, Fang ancestral sculpture of Equatorial Africa figured among the most emblematic and esteemed genres of African art. These anthropomorphic effigies..."
To learn more about this world famous Fang head (byéri) and its radiological analysis, see:
A Masterwork that Sheds Tears... and Light - A Complementary Study of a Fang Ancestral Head
Roland Kaehr, Louis Perrois & Marc Ghysels
African Arts, Winter 2007, vol. 40(4), p.44-57 — free access: http://goo.gl/7oCgcs