In this fetus , sonography of the lumbosacral spine shows a major defect in the posterior part of the fetal lumbar and sacral vertebrae due to failure of closure of the dorsal part of the vertebrae (the laminae and spinous processes). The ultrasound image in top , shows 2-D (B-mode) display of the large defect in long section. The image on middle, shows the same appearance in 3-D ultrasound.
The post natal photograph of the area (lower back) shows the open spinal canal. This type of spina bifida is called spina bifida cystica. (Ultrasound images of spina bifida are courtesy of Dr. Martin Horenstein, Argentina).