Page 25 - SONO 260 The Fetal Head and Brain
P. 25

  FETAL HEAD MEASUREMENTS CEPHALIC INDEX AND FETAL HEAD SHAPE
 — These abnormal shapes are associated with fetal anomalies. — The normal- to medium-sized skull is termed mesocephalic.
The formula used to calculate the cephalic index considers the biparietal diameter and the occipitofrontal diameter as in: cephalic index = BPD/OFD × 100.
— Fortunately, the formula is calculated by the majority of present-day equipment.
— A cephalic index of less than 75 denotes a dolichocephalic shape, while an index of greater than 85 denotes a brachiocephalic shape.
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