RIU 332 Lecture Notes - Lecture 71: Yolk Sac, Gestational Sac, Gestational Age
24 Apr 2020
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6 to 12 gestational weeks: measurements should be made along long axis of embryo from top of head (crown) to bottom of trunk (rump, is most accurate fetal age measurement. Embryonic heart rate (ehr: ehr can be measured by m-mode from early fifth to early ninth gestational weeks when crl < 25mm, most accurate ehr measurements obtained by enlarging 2d image and using fast sweep speed for. Alterations in the head shape: dolichocephaly - head is shortened in transverse plane (bpd) and elongated in the anteroposterior plane (ofd) B: brachycephaly-head is elongated in transverse plane (bpd) and shortened in the anteroposterior plane (ofd) Cephalic index: ci= bpd/ ofd/100, range of normal- 75 to 85, ci < 0. 70- dolichocephaly, ci> 0. 86- brachycephaly. Orbital measurements mm or greater at term: orbital diameter increases from 13 mm at 12 weeks to 59, measure outer to outer diameter (bd, measure inner to inner diameter (iod )
