ABSTRACT
The second change that shortened the SVTH was the anterior migration of the foramen magnum and the cervical spine. This is shown in Fig. 6. Examination of primate skulls shows that the foramen magnum is located more anteriorly the closer one gets to modern man (13). While one could opine that this helped balance the forward enlarging cranium and favored bipedalism, one can also opine that this further shortened the horizontal segment of the SVT, thereby improving speech. Keep in mind that the further the larynx descends, the longer the oropharynx extends, the more the respiratory and alimentary tracts overlap, and the more at risk is man of aspiration and asphyxiation.
