Aim: Many authors have included the V2 segment of the trigeminal nerve as a component of the cavernous sinus. However, many authorities have stated that this part of the fifth cranial nerve is not within this intracranial venous sinus. Materials and methods: To further elucidate this potentially important relationship, 10 fresh cadaveric heads underwent injection of the cavernous sinus with blue latex or a cresyl-violet solution. Subsequent sectioning in the coronal plane in 1 cm sections from the level of the trigeminal ganglia anteriorly to the level of the superior orbital fissure was made. Observations were then made between the relationships of the cavernous sinus and the V2 nerve. Results: On all 20 sides, the V2 segment of the trigeminal nerve did not have filling of latex or cresyl-violet mixture lateral to it thus implying that this part of the trigeminal nerve is not found within the cavernous sinus. Two sides did demonstrate an emissary vein that traveled with the V2 part of the trigeminal nerve through the foramen rotundum toward the cavernous sinus. Conclusions: Based on our findings, the V2 part of the trigeminal nerve is not found bathed with venous blood within the cavernous sinus. Reports that state the contrary may have confused laterally positioned emissary veins as being part of the cavernous sinus and therefore erroneously concluded that V2 was within this cranial venous sinus. These data may prove useful to neurosurgeons that operate in the region of the cavernous sinus or to radiologists who interpret imaging of this area. © Springer-Verlag 2007.