Neuro-skeletal topology of the primate basicranium: its implications for the "fetalization hypothesis".

The data above, and the literature reviewed, demonstrate that in 4 significant morphological characteristics the neuro-skeletal topology of the human basicranial regions is unique, and does not resemble that of any extant non-human primate at any fetal or postnatal age. These characteristics are: 1. the shape of the cranial base; 2. the composition of the anterior and posterior portions of that base; 3. the extent, or degree, of basicranial flexion; and 4. the extent, or degree, of brain flexion. On these bases, the craniological implications of Bolk's fetalization hypothesis cannot be supported.