Background:Within the midbrain,the third nerve nucleus is composed of a complex of subnuclei.The fascicular portion of the nerve courses through the red nucleus and exists in themidbrain just medial to the cerebral pe...Background:Within the midbrain,the third nerve nucleus is composed of a complex of subnuclei.The fascicular portion of the nerve courses through the red nucleus and exists in themidbrain just medial to the cerebral peduncle.The cisternal portion of the nerve is a single structure that divides into a superior branch and an inferior branch in the region of the cavernous sinus and superior orbital fissure.Objective:To describe 2 patients with superior divisional third cranial nerve paresis resulting froma lesion involving the cisternal portion of the nerve prior to its anatomical bifurcation.Patients:Case 1 was a 77-year-old man with a superior divisional third nerve palsy as the presenting manifestation of a posterior communicating artery aneurysm.Case 2 was a 41-year-old woman who developed a superior divisional third nerve palsy following anterior temporal lobectomy for epilepsy.Results:In both cases,the presumed location of the lesion was the cisternal portion of the third cranial nerve.Conclusions:Although the anatomical division of the third cranial nerve occurs in the region of the anterior cavernous sinus or superior orbital fissure,there is a topographical arrangement of the motor fibers within the cisternal portion of the nerve.The clinical evaluation of a patient with a third cranial nerve paresis requires an understanding of the regional neuroanatomy and topographical organization of the nerve.展开更多
文摘Background:Within the midbrain,the third nerve nucleus is composed of a complex of subnuclei.The fascicular portion of the nerve courses through the red nucleus and exists in themidbrain just medial to the cerebral peduncle.The cisternal portion of the nerve is a single structure that divides into a superior branch and an inferior branch in the region of the cavernous sinus and superior orbital fissure.Objective:To describe 2 patients with superior divisional third cranial nerve paresis resulting froma lesion involving the cisternal portion of the nerve prior to its anatomical bifurcation.Patients:Case 1 was a 77-year-old man with a superior divisional third nerve palsy as the presenting manifestation of a posterior communicating artery aneurysm.Case 2 was a 41-year-old woman who developed a superior divisional third nerve palsy following anterior temporal lobectomy for epilepsy.Results:In both cases,the presumed location of the lesion was the cisternal portion of the third cranial nerve.Conclusions:Although the anatomical division of the third cranial nerve occurs in the region of the anterior cavernous sinus or superior orbital fissure,there is a topographical arrangement of the motor fibers within the cisternal portion of the nerve.The clinical evaluation of a patient with a third cranial nerve paresis requires an understanding of the regional neuroanatomy and topographical organization of the nerve.
