眼外肌的断层解剖及其临床意义

Sectional Anatomy of Extraocular Muscles and Its Clinical Significance

目的:为临床眼外肌疾病及其并发症的影像学诊断提供形态学资料。方法:固定成人尸体头颅15个,经低温冷冻后,利用MJ-346B型电动带锯做眼眶连续冠状断层(层厚0.5cm,锯耗0.1cm),观测眶尖至眼球后极5个连续层面上眼外肌的宽、厚、断面面积及其与视神经、眶壁的位置关系。结果:眼外肌厚、断面面积最大值均分布于眶的第3或第4层面,眼外肌断面面积之和的最大值在第4层面,其面积和平均为128.54mm^2,而第3层面眼外肌断面面积之和占眶断面面积的比例最大,平均占29％;内直肌与上斜肌、视神经的距离最近,因而其毗邻关系最为密切:结论:内直肌的病理性肥大对视神经的压迫更为直接;当多条眼外肌同时肥大时,第3层面的影像表现更能反映眼外肌对视神经的压迫程度;还可通过眶断面影像上的几个简便测量来评估眼型Graves病人发生视神经病变的可能性。

Objective: To provide morphological basis for the imageologic diagnosis of extraocular muscles' (EOMs) diseases and their complications. Methods: Frozen fixed orbits of adult cadavers were sawed on marker lines at an interval of 0.5cm to get the serial coronal sections of orbits. Width, thickness,and area of each muscle as well as its positional relations to optic nerve (ON) and orbital wall on 5 consecutive sections of orbits from orbital apex to posterior globe were observed and measured. Results: Maxima of the thickness and area of EOMs lie in section 3 or 4, and section 4 holds maximum of the sum of EOMs' areas, but section 3 possesses maximum of the ratio of the EOMs' areas sum to the orbital area. Medial rectus (MR) adjoins close to superior obliquus and ON. Conclusion:The pathologic enlargement of MR more directly impinges on ON. The compression of ON by multiple enlarged muscles can be more accurately reflected on the image of section 3. The developing likelihood of optic neuropathy in Graves' Ophthalmopathy patients can be evaluated through the simphe measurements of orbital image.