An Anatomic Study of the Intercavernous Sinuses

Background: As expanded endoscopic endonasal approaches are gaining popularity, a thorough understanding of the anatomy of the intercavernous sinuses is pertinent to avoid bleeding complications. There have been few studies reporting the presence and dimensions of the anterior (AIS), posterior (PIS), and inferior (IIS) intercavernous sinuses. We therefore performed a cadaveric study to better understand these structures.

Methods: Colored latex was injected into the arterial and venous trees of fifteen cadaveric heads. Dissections were then performed to assess the presence and dimensions of the anterior, posterior, and inferior intercavernous sinuses.

Results: In nine specimens (60%), all three sinuses were identified. In five specimens (33%), only the anterior and posterior intercavernous sinuses could be identified, and in one specimen, only anterior and inferior sinuses were identified. An anterior intercavernous sinus was identified in 100% of specimens, posterior intercavernous sinus in 93%, and an inferior intercavernous sinus in 66%. In two specimens (13%), the anterior intercavernous sinus covered the entire face of the sella. The average dimensions for the sinuses were as follows: AIS,1.7 ± 0.8 mm anterior–posterior, 11.7 ± 2.2 mm medial–lateral, 2.8 ± 1.2 mm dorsal–ventral; PIS, 1.5 ± 0.5 mm anterior–posterior, 10.8 ± 2.3 mm medial–lateral, 1.7 ± 0.6 mm dorsal–ventral; IIS, 8.7 ± 3.4 mm anterior–posterior, 11.8 ± 4 mm medial–lateral, 1.0 ± 0.8 mm dorsal–ventral.

Table 1 Intercavernous sinus frequencies in the literature

Conclusion: All examined specimens in our study demonstrated the presence of an anterior intercavernous sinus, and most also had a posterior intercavernous sinus. The presence of an inferior intercavernous sinus was more variable.