The abducens nerve

Abstract

✓ The authors describe the origins and course of the sixth cranial nerve in 62 cadaver or autopsy cases and describe three patterns. In Pattern 1 the nerve originates and runs all its way as a single trunk. In Pattern 2 it originates as a single trunk, but splits into two branches in the subarachnoid space, while in Pattern 3 it originates as two separate trunks. In both Patterns 2 and 3 the trunks perforate the dura mater independently and enter the cavernous sinus by passing one above and the other below the petrosphenoidal ligament. In the sinus the two trunks fuse into a single trunk which then continues to the lateral rectus muscle. The practical neurological importance of these variations is discussed.