在细胞减数分裂的前期，同源染色体之间形成的接触点。
结论术后视力下降可能为鞍区肿瘤经颅手术误伤视神经或视交叉所致。
当然，选专业还要尽量选一些细分型、交叉型、实用型专业。
1·The small branches seen anteriorly to optic chiasma in the chiasmatic cistern were almost always the branches of superior hypophyseal artery.
在视交叉池内，垂体柄前方所见的小动脉几乎均属于垂体上动脉的分支。
2·The results indicated that both the number of rod bivalents and the number of pre-division bivalents increased markedly after radiation, while the number of bivalent chiasma tended to decrease.
结果表明，照射后棒状二价体数明显上升，二价体提前分离增多，而二价体的交叉数却呈下降趋势。
3·Objective To provide morphological evidences for visual field defects caused by the compression of optic nerves and optic chiasma by saddle area tumors.
目的为脑底肿瘤压迫视神经、视交叉引起视野缺损原因提供形态学依据。
4·Today, with the changing quickly computer technology and in-depth subjects chiasma, the traditional safety monitoring work is being endowed with much more new content.
在计算机技术日新月异，学科交叉日趋深入的今天，传统的安全监测工作正被赋予更多新的内容。
5·Results Orbit tumor of a 21 year old young lady extends the encephalic and endangers the olfactory nerve and optic chiasma, even cause olfaction and visual acuity to be declined.
结果1例2 1岁女性患者，眼眶肿瘤侵入颅内损伤嗅神经及视交叉，引起嗅觉及视力下降。