Intercavernous venous communications in the human skull base.

The intercavernous communications of the skull base were studied in 32 sphenoid blocks using electrolytic decalcification techniques, vascular filling, x-rays, and serial anatomical sections. In this study four intercavernous connections were found: anterior intercavernous sinus (AIS), posterior intercavernous sinus (PIS), inferior intercavernous sinus (IIS), and basilar plexus (BP). The AIS was present in 100% of the cases, with diameters ranging from 0.57 mm to 5.43 mm; in 17 cases (53.12%) it took up the whole anterior wall of the hypophyseal fossa. The PIS was also detected in 100% of the cases, and its diameters ranged from 0.71 mm to 4.14 mm. The IIS was identified in 31 cases (96.9%), assuming three different forms: plexuslike, venous lake, and mixed. The BP was found in 100% of the material analyzed; in 23 cases (71.9%) it proved to be the widest intercavernous communication.In 12 cases of this series the hypophysis was completely enveloped by venous structures, except at the level of the sellar diaphragm.