Scanning electron microscopy of femoral ossification in the human foetus

The ossification of human femoral bone was studied in 10 fetuses aged from 8 to 40 weeks, and in a 3 1/2 month-old child. After dissection and radiographic examination, each femur was sectioned in a sagittal plane. One part was processed for routine histology, the remaining one for scanning electron microscopy. By comparing the radiographic, light microscopic and scanning electron microscopic pictures, it is possible to precise the pattern of ossification and to define 3 main periods during human fetal development (pure cartilage, metaphyseal and diaphyseal ossification, constitution of a cortex and a medulla in the diaphysis).