Microsurgical Anatomy of the Lateral Wall and Cranial Nerves of the Cavernous Sinus

Yoon, Do Heum; Lee, Kyu Chang; Choi, Joong Uhn; Suh, Jai Kwan

Abstract

The cavernous sinus is a extradural venous pathway enclosed by leaves of dura and periosteum located on either side of the sella turcica, and has connections with cerebrum, cerebellum, brain stem and orbit. It contains the internal carotid artery, the abducens nerve, and the sympathetic nerves, and its lateral wall contains the third and fourth cranial nerves as well as the first and sometimes the second division of the fifth cranial nerve. These connections and the relationships make the sinus of special interest to neurosurgeons. However, the descriptions of the cavernous sinus and its contents show great variation in books and journals. To better define this anatomy, in this report, eighty cavernous sinuses from fresh cadavers were studied in detail using surgical microscope with special attention to the relationships imprortant in surgical approaches on the intracavernous structures, and twenty cavernous sinuses were studied, based on serial sections in the coronal planes for the study of the microanatomical structures. The results of this study were summarized as follows : 1) The average distance between the posterior clinoid process and the entrance of the 3rd, 4th, 5th, 6th cranial nerve into the cavernous sinus were 5.99+/-1.69, 12.00+/-2.83, 15.44+/-2.38, 17.85+/-3.12mm. 2) The lateral wall of the sinus was composed of two layers : a deep layer is formed by the sheathes of nerve III, IV, and VI with a reticular membrane and some dural fold, and the deep layer was less defined and more irregular and imcomplete. 3) The average length of the Parkinson's striangle was 14.76+/-3.40mm(superior), 18.54+/-3.96mm(inferior), 6.33+/-2.14mm(posterior). 4) There were many variations in the origin and course of the sixth nerve. Among these, calssic pattern which originated and run all its course to the orbit as a single trunk is 67.5%.