The occipital horn of the lateral ventricles in premature infants. An ultrasonographic study.

The size of the occipital horn of the lateral ventricles was determined on parasagittal ultrasound scans in premature infants. In 52 neonates without evidence of intracranial haemorrhage, the pulvinar-posterior horn wall distance measured an average of 11.6 mm +/- 2 mm. In infants with intracranial pathology, the average length of the occipital horn varied from 16.3 mm +/- 2.5 mm to 31.8 mm +/- 7.4 mm. An occipital horn measurement greater than 16 mm indicated ventricular enlargement. Occipital horn asymmetry also indicated ventricular dilatation. In normal neonates the side-to-side difference averaged 0.6 mm while in neonates with ventriculomegaly the mean difference was 2.6 mm. The occipital horn frequently represents the first and may represent the only portion of the lateral ventricle to enlarge. Precise measurement of the occipital horn dimension, therefore, represents an excellent method for the identification and follow-up of ventriculomegaly in premature neonates.