【讲座】关于胎儿远离探头侧股骨“弯曲”的原因
这个帖子发布于 16 年零 42 天前，其中的信息可能已发生改变或有所发展。
今天已经是这次下乡的第三个月，乡下轻松无比的工作使自己可以静下心来学习，一段时间下来发现原来需要学习的东西很多。关于B超时经常会发现远离探头一侧的股骨“弯曲”的现象原来在园子里也有讨论，
http://www.dxy.cn/bbs/actions/archive/post/8481421_1.html
平时进修生问到我，我也只是模糊的回答切面不同，超声角度不同引起的，但自己心里也没有底。
今天在网上看到了关于这个问题的答案，才恍然大悟，哦，原来是这样。把它贴过来，是英文的，回头再翻译。
It is important to clarify that sonography has the capacity to visualize not only the ossified portions of the fetal skeleton but also the cartilaginous portions.13 Cartilaginous ends of the long bones may be seen by the early second trimester. Indeed, bones entirely in cartilage can be seen sonographically (Fig. 20). It is equally important to recognize that the full thickness of the ossified diaphysis of long bones is not seen sonographically.40 This is due to acoustic shadowing. The cartilaginous ends of long bones help us to recognize this aberration. By matching up the width of the epiphysis, the full thickness of which can be seen, with the apparent “width” of the bony diaphysis, it is clear that these are unequal (Fig. 21 and Fig. 22). This observation helps to correct some perceptual errors that can lead to erroneous diagnoses. For example, the inability to see the full thickness of the femoral diaphysis creates the impression that the fetal femur farther from the transducer is bowed (Fig. 23).40 This error is caused by visualization of only the medial cortex of the femoral diaphysis (which is normally curved) (Fig. 24). However, the inability to “visually correct” this normal curvature by simultaneous observation of the “straight” lateral cortex causes the perceptual error
今天在网上看到了关于这个问题的答案，才恍然大悟，哦，原来是这样。把它贴过来，是英文的，回头再翻译。
It is important to clarify that sonography has the capacity to visualize not only the ossified portions of the fetal skeleton but also the cartilaginous portions.13 Cartilaginous ends of the long bones may be seen by the early second trimester. Indeed, bones entirely in cartilage can be seen sonographically (Fig. 20). It is equally important to recognize that the full thickness of the ossified diaphysis of long bones is not seen sonographically.40 This is due to acoustic shadowing. The cartilaginous ends of long bones help us to recognize this aberration. By matching up the width of the epiphysis, the full thickness of which can be seen, with the apparent “width” of the bony diaphysis, it is clear that these are unequal (Fig. 21 and Fig. 22). This observation helps to correct some perceptual errors that can lead to erroneous diagnoses. For example, the inability to see the full thickness of the femoral diaphysis creates the impression that the fetal femur farther from the transducer is bowed (Fig. 23).40 This error is caused by visualization of only the medial cortex of the femoral diaphysis (which is normally curved) (Fig. 24). However, the inability to “visually correct” this normal curvature by simultaneous observation of the “straight” lateral cortex causes the perceptual error
