cephalic index
The cephalic index (CI) is a value calculated using two fetal biometric parameters which are the occipitofrontal diameter (OFD) and the biparietal diameter (BPD).
It is calculated as:
- cephalic index (CI) = biparietal diameter (BPD)/occipitofrontal diameter (OFD) x 100
The cephalic index gives an idea of the fetal head shape. It can change according to various situations such as
- presentation, e.g. breech presentation
- ruptured membranes
- presence of a twin pregnancy
The usual range is variable depending on various sources and different demographic groups. Often the mean value is taken ~78 (range 74-83 )
A grossly decreased cephalic index suggests dolichocephaly while a grossly increased one can suggest brachycephaly.
Siehe auch:
Assoziationen und Differentialdiagnosen zu cephalic index:
