Histological examinations of bone and cartilage in the axial skeleton of human triploidy fetuses.

The aim of this study was to examine histologically bone and cartilage in vertebral corpora of axial skeletons of eight human triploid fetuses, gestational ages 14-25 weeks, CRL 100-200 mm. The results were compared to earlier studies on vertebral development in trisomies 21, 18, 13, and to normal corpora development. After radiography in frontal and lateral projections, the vertebral column was sectioned into cervical, thoracic and lumbar segments, decalcified, dehydrated, and embedded in paraffin. The blocks were serially sectioned in the vertical plane and stained with Toluidine blue and Alcian blue/van Gieson. The radiographic characteristics of the vertebral corpora observed in frontal and lateral projection varied from small cleft vertebral corpora to fusions between the individual corpora. Histological examination of the vertebral corpora confirmed the abnormal pattern of ossification seen radiographically. As a new finding abnormal metachromasia of the ground substance was observed in the cartilage. Marked borderlines were registered in the cartilage between regions with differences in metachromasia. These borderlines were similar but more extensive than borderlines observed previously in trisomies 21, 18 and 13.