Left cavernous sinus. The short ascending cavernous ICA has been gently displaced medially to access the lateral compartment of the cavernous sinus. In order to safely mobilize the cavernous ICA medially, it is important to identify and selectively coagulate and transect the infero-lateral arterial trunk, which typically arises from the proximal horizontal cavernous ICA. The abducens nerve enters the lateral compartment and joins first trigeminal division, trochlear, and oculomotor nerves. The lateral compartment is a virtual space that can be potentially be expanded by tumor growth. (Image courtesy of JC Fernandez-Miranda)