视交叉三维断层影像解剖学观察

目的 通过连续横、矢、冠状断层，探讨成人视交叉的位置、形态、毗邻结构及其变化规律，获取视交叉的三维径线和角度数据。方法 20例成人尸体头颅制成头部连续横、矢、冠状断层标本与40例活体成人头部磁共振横、矢、冠状断层扫描图像，探讨视交叉的位置、形态及其毗邻结构；测量视交叉的横径、前后径和上下径，视交叉前角、侧角和后角。 结果 视交叉横断层能同时显示视神经颅内段、视交叉和视束起始段；冠状断层视交叉呈“一”字型横位分隔第三脑室底的视隐窝和漏斗隐窝，其上方是大脑前动脉A1段，下方正中邻垂体柄和灰结节，两侧是颈内动脉C1或C2段；视交叉的横径 (TD_T)为（13.54±3.12）mm，前后径 (APD_T)为（7.91±1.29）mm，上下径 (SID_C)为（3.51±0.49）mm，视交叉前角(AA)为（69.7±9.1）°，左侧角（LLA)为（121.1±16.9）°，右侧角（RLA)为（122.3±15.2）°，后角（PA)为（73.3±10.2）°。断层数据和MRI数据经统计学分析，两者差异无显著性。 结论 连续横、矢、冠状断层和MRI是研究和辨认视交叉、毗邻结构的位置关系及其变化规律的有效方法。

Three-dimensional sectional imaging anatomy of the optic chiasma

Objective To study the position，shape，adjacent structures and change rule of the adult optic chiasma, and to obtain its three-dimensional data of distance and angle from the serial thin transverse, sagittal, and coronary planes. Methods The three-dimensional data of distance and angles were collected from on 20 sets of serial transverse, sagittal, coronary sections of Chinese adult cadaveric heads and from 40 sets of serial transverse, sagittal, and coronary MRI of normal adult living subjeats. Transverse,superoinferior and anteroposterior diameters of the optic chiasma, anterior, lateral and posterior angles of the optic chiasma were measured. Results On the transverse plane, optic intracranial segment, optic chiasma and initial part of the optic tract were clearly displayed. The chiasma was transversed between the optic and infundibular recesses of the floor of the third ventricle and it located inferio to the A1 segment of the anterior cerebral artery, superior to the tuber cinereum and the pituitary stalk, and lateral to the C2 or C3 segment of the internal carotid artery. The mean transverse diameter in transverse section(TD_T) of the optic chiasma was (13.54±3.12)mm , anteroposterior diameter in transverse section(APD_T) was (7.91±1.29)mm , superoinferior diameter in coronal section (SIDC) was (3.51±0.49)mm, anterior angle(AA) was (69.7±9.1)°, left lateral angle(LLA) was (121.1±16.9)°, right lateral angle (RLA)was (122.3±15.2)°, and posterior angle(PA) was (73.3±10.2)°.There was no significant difference between the sectional data and MRI data by statistics. Conclusion Examination of the serial thin transverse, sagittal, and coronary planes and MRI is an effective methods to study and identify the spatial relation and the change rules of the optic chiasma.