basilar plexus basilar plexus the basilar plexus (transverse or basilar sinus) consists of several interlacing venous channels between the layers of the dura mater over the basilar part of the occipital bone (the clivus), and serves to connect the two inferior petrosal sinuses. basilar plexusthe sinuses at the base of the skulldetailsidentifierslatinplexus basilarista98a12.3.05.106ta24866fma50783anatomical terminology it communicates with the anterior vertebral venous plexus.