title: Letter: Ultrasonic cephalometry.
mesh_terms: D002508:Cephalometry; D005314:Embryonic and Fetal Development; D005260:Female; D005865:Gestational Age; D006257:Head / Q000196:embryology; D006801:Humans; D011247:Pregnancy; D011296:Prenatal Diagnosis; D014463:Ultrasonography