vertebral segmentation defects

diagnosis

the spine should be examined carefully as the demonstration of scoliosis or spinal angulation can be the clue to the presence of other vertebral anomalies. longitudinal views of the vertebral bodies allow for comparison between the different segments of the spine, the size of the vertebral bodies and the intervertebral spaces. coronal scans are also useful, particularly in cases of severe vertebral disorganisation (eg; dyssegmental dysplasia, jarcho-levin syndrome) and sagittal clefts. coronal clefts are best seen in cross sectional views of the vertebral bodies. they are characterized by an echolucent band of tissue located between the anterior and posterior echogenic ossification centers of the vertebral body. spinal angulations are usually the result of hemivertebrae. identification of hemivertebrae with a normal spine axis is often difficult and is most often diagnosed postnatally. absent ossification of half of the sacrum (hemisacrum) may be an isolated finding or a syndromic feature. coronal and cross-sectional views will demonstrate the unilateral ossification defect, although visualization of this area is often impaired by shadowing from the iliac wings. vertebral fusion can be identified easily in longitudinal and coronal planes by demonstrating absence of the echolucent intervertebral space.