Course and relations of the abducens nerve

The authors describe the course and relations of the abducens nerve in the posterior cranial fossa and in the cavernous sinus, observed during the dissection of 60 hemi-heads of cadavers of brazilian adult individuals of both sexes. It was observed that the abducens nerve after crossing the cranial dura mater it, in most cases, goes through the interior of the inferior petrosal sinus, and in few cases the lateral wall of this sinus. At this level, the nerve is attached to the sinusal wall by means of delicate fibrous septum. Afterwards, the abducens nerve passes inferiorly to the petroclinoid ligament and crosses medially the superior petrosal sinus, thus reaching the cavernous sinus, where it stands laterally to the internal carotid artery. Measurements of the abducens nerve penetration point in the dura mater of the posterior cranial fossa also were made. For these above mentioned measurements we used the jugular tubercle of the occipital bone as landmark.