On prenatal ultrasound, the nasal bone is a thin echogenic line within the bridge of the fetal nose. The fetus is imaged facing the transducer with the fetal face strictly in the midline. The angle of insonation is 90 degrees, with the longitudinal axis of the nasal bone as the reference line. Calibres are placed at each end of the nasal bone. Absence of the nasal bone or measurements below 2.5th percentile are considered significant (PMID:16100637).
Lemon sign
Mild fetal ventriculomegaly
Reduced fetal femur/foot length ratio
Short fetal femur length
Short fetal humerus length
Single umbilical artery
Thickened nuchal skin fold
Synonyms
Exact Synonyms:
Hypoplasia of foetal nasal bone
;
Underdeveloped fetal nose bone
;
Underdeveloped foetal nose bone