notancephalia

Fetal malformation characterized by absence of the occipital bone of the cranium. [G. notos, back, + an- priv. + kephale, head]

* * *

no·tan·ce·pha·lia (no″tən-sə-faґle-ə) [not- + an- + cephal- + -ia] congenital absence of the posterior aspect of the cranium.