眶内眼神经的断层解剖与MRI的对照研究

The ophthalmic nerve in orbit:a comparative study between cross-sectional anatomy and magnetic resonance imaging

目的为眶内手术及MRI诊断提供解剖学基础。方法采用成人尸头6例(12侧)制成0.5mm的火棉胶连续切片;再选择健康志愿者15例(30侧)行MRI的水平位、冠状位扫描,对额神经、鼻睫神经和泪腺神经位置、走行和毗邻进行观察和识别,并与相应活体MRI图像对照研究。结果眶内眼神经的分支额神经、鼻睫神经和泪腺神经均经过眶上裂入眶;额神经发出眶上神经内外支和滑车上神经,鼻睫神经与眼动脉伴行,泪腺神经在外直肌上方前行。活体MRI眶内眼神经扫描,T1WI、T2WI及其各脂抑加权像上眶内眼神经呈中等信号。结论MRI检查时,宜选择水平位观察额神经并显示最佳,选择冠状位观察鼻睫神经及泪腺神经,鼻睫神经显示尚可,泪腺神经显示不清;与MRI对应的火棉胶连续切片能准确显示眶内眼神经的分支、走形,且其制备技术是研究眶内眼神经的一种简单、经济、切实、可行的方法。

Objective To provide sectional-anatomic data for MR imaging diagnosis and avoiding damage during the intraorbital operation. Methods Twelve orbit specimens of adult cadaver heads were examined and cut into continuous slices （0.5 mm thickness）by using celloidin embedding technique, and a total of 30 healthy volunteers （control group） were further selected for cross and coronal section scanning by MRI. The location, pathway and relationship of the frontal, nasociliary and lacrimal nerve were observed and marked for comparison with images of MRI. Results The frontal, nasociliary and lacrimal nerve entered the orbit via the superior orbital fissure. The frontal nerve branched into supratrochlear nerve and medial and lateral branch of supraorbital nerve. The nasociliary nerve accompany with the ophthalmic artery. The lacrimal nerve lies superiorly to the superior rectus muscle. The ophthalmic nerve in orbit showed intermediate signal intensity on T1-weighted images and T2-weighted images of MRI scan. Conclusions The frontal nerve can be well showed in cross section, nasociliary can be well displayed in coronal section, lacrimal nerve can not be easily showed. The method of contiguous thin slices of classical celloidin embedding matched with the corresponding MRI image is simple, economical and accurate in studying sectional-orbit structures.