oxycephaly

from The American Heritage® Dictionary of the English Language, 5th Edition.

• noun A congenital abnormality of the skull in which the top of the head assumes a conical or pointed shape.

from The Century Dictionary.

• noun The character of a skull having a high vertical index; hypsicephaly.
• noun In anthropology, the head-form resulting from artificial deformation applied all around the head and preventing lateral and occipital growth, thus making the head very high in the region of the bregma. Similar forms result from premature synostosis of the parietals with the occipital or temporal bones.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• noun A kind of cephalic disorder: sometimes the premature closure of the coronal suture plus any other suture, such as the lambdoid; sometimes the premature fusing of all sutures.

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

• noun a congenital abnormality of the skull; the top of the skull assumes a cone shape