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Absent nasal bone

Dr Abhilash Sandhyala and Dr Yuranga Weerakkody et al.

In fetal sonographic assessment, an absent nasal bone is a feature which can sometimes be used as an adjunctive marker for fetal aneuploidy.

Radiographic assessment

Antenatal ultrasound

It is assessed on a midline sagittal view. There nasal bone is often seen as a bright echogenic line. It is best measured at around the 11^th to 14^th weeks of gestation (1^sttrimester). A magnified image may assist in visualisation.

When the mid sagittal view is difficult to assess, some authors suggest coronal view of the fetal face to look for paired echogenic structures located at the upper tip of the retronasal triangle ⁶.