Sepulveda W, Treadwell M C, Fisk N M
Centre for Fetal Care, Royal Postgraduate Medical School, London, United Kingdom.
Obstet Gynecol. 1995 May;85(5 Pt 2):847-50. doi: 10.1016/0029-7844(94)00284-k.
Abnormalities of the upper and lower extremities, such as club feet, rocker-bottom feet, and abnormal hand posturing, are frequently detected prenatally in trisomy 18 fetuses. Aplasia of the radius, usually associated with the absence or hypoplasia of the first metacarpal and thumb, is the most prevalent reduction malformation in trisomy 18 infants. Because this anomaly is easily missed during prenatal ultrasonography, the role of prenatal detection of this particular preaxial upper limb reduction has not been emphasized.
Three cases of trisomy 18 in which preaxial upper limb reduction (radial aplasia) was identified prenatally by ultrasound are reported. Although in all cases there were additional ultrasonographic findings suggestive of trisomy 18, the prenatal detection of preaxial upper limb reduction facilitated the diagnosis.
Ultrasonographic examination of fetal forearms for the detection of preaxial upper limb reduction should be a routine part of the prenatal evaluation of fetuses in whom trisomy 18 is suspected.
上肢和下肢异常，如马蹄内翻足、摇椅底足和手部姿势异常，在18三体胎儿中常于产前被检测到。桡骨发育不全通常与第一掌骨和拇指缺如或发育不全相关，是18三体婴儿中最常见的肢体减少畸形。由于这种异常在产前超声检查中容易被漏诊，因此产前检测这种特定的上肢轴前减少畸形的作用尚未得到重视。
报告了3例18三体病例，其中产前超声检查发现了上肢轴前减少（桡骨发育不全）。尽管在所有病例中均有其他超声检查结果提示18三体，但上肢轴前减少的产前检测有助于诊断。
对胎儿前臂进行超声检查以检测上肢轴前减少，应作为疑似18三体胎儿产前评估的常规部分。
