A study on the sectional anatomy of the oculomotor nerve and its related blood vessels with plastination and MRI.

To obtain normal images and sectional anatomical data of the oculomotor nerve and its related arteries, the optimal angles and the length of intracisternal segment of the oculomotor nerve were measured on MPR images. Meanwhile, the relationships between the nerve and the basilar, posterior cerebral, superior cerebellar and posterior communicating arteries were observed from plastination slices, original images, MPR and MIP images. MRI revealed similar results to the plastination sections. The intracisternal segment of oculomotor nerve formed an angle with the posterior plane of the brainstem. The angle was significantly smaller in individuals under 10 and over 50 years old ( P<0.05), and there was no marked difference in the angle between the oculomotor nerve and the median sagittal plane among the different groups ( P>0.05). Shift of the basilar artery was more likely to be found in aged individuals. Most of the posterior cerebral and superior cerebellar arteries were close to the nerve, and a few of them seemed to compress it; for the posterior communicating artery, only the embryonic type was close to or seemed to compress the nerve. MRI is an accurate imaging technique for determination of the relationship of the oculomotor nerve to its related arteries.