Fig 3.

Relationship between the CSA of the IJVs and the CSA of the NJVs. Initially, the NJVs were regarded as a complete drainage system. This system was then further divided to its components (vertebral plexus and pterygopalatine plexus). The most significant correlation was found when the IJVs were compared with the NJVs as a whole system (A). When the NJVs were divided into their components — vertebral plexus (B) and pterygopalatine plexus (C) — the correlation was still significant though less prominent.