[Evolution of median menigeal veins network in primates, from endocranial imprint patterns]

In the evolution of Primates, three main changes in the endocranial imprint pattern of the median meningeal veins are observed: 1. a gradual increase in the arrangement of the three-branched network: 2. a progression of the complexity of the anastomotic squaring; 3. the consecutive disappearnce of the retroarticular system (external jugular vein), which brings about an enlargement of the available space for the internal jugular system, and the ensuing increase in functional importance of the pterygoid plexus.