THE VENTRICULUS TERMINALIS OF THE SPINAL-CORD IN THE NEONATE - A NORMAL VARIANT ON SONOGRAPHY

OBJECTIVE. The ventriculus terminalis, or fifth ventricle, is an epend ymal-lined residual lumen of the caudal most portion of the spinal cor d (the conus medullaris). We describe five neonates in whom this norma l variant was depicted on sonography. MATERIALS AND METHODS. Screening lumbosacral spinal sonograms are performed at our institutions on neo nates with lumbosacral cutaneous stigmata. Over a 2-year period (1993- 1995), we prospectively found five cases in which spinal sonograms sho wed the ventriculus terminalis of the conus medullaris in term neonate s. Two of the five received follow-up spinal sonograms at the age of 3 months.RESULTS. Sonograms of the lumbosacral spine of these five neon ates showed an unusual hypoechoic or split appearance of the central e cho complex of the conus medullaris. No other abnormalities were noted , and the finding was unchanged on the followup sonograms performed on two of the infants at the age of 3 months. These infants have remaine d asymptomatic during clinical follow-up periods of up to 2 years. CON CLUSION. The ventriculus terminalis is a normal anatomic variant of th e conus medullaris that can be visualized on spinal sonograms in neona tes.