The ossification of the vertebral column, thorax and sternum in the quail (Coturnix coturnix japonica)

The ossification centers onset of the quail vertebrae, ribs, and sternum in embryos and hatchling birds was studied. Specimens were cleared, stained with Alcian Blue and Alizarin Red S and examined using stereomicroscope. The chondral rudiments of the vertebrae were observed at the 6th day of incubation (E6). The osteogenesis of the vertebrae was accomplished with both perichondral and endochondral ossifications. The cervical vertebrae began to ossify at E9-E10, whereas the thoracic ones began at E10-E11. The synsacral vertebrae began to ossify at E11-E13. In the caudal vertebrae, ossification was observed at E14 and in the pygostylous ones, at E15. The true ribs began to ossify at E7, whereas the 1st and the 2nd ribs began to ossify at E9 and E8, respectively. The uncinate processes were ossified late at E15. At E13, ossification was observed in the caudo-lateral process of the sternum. At E14, the cranio-lateral process of the sternum began to ossify, whereas late at and after hatching ossification was observed in the carina and the sternal body, respectively. The data presented here provide useful baseline information on the normal sequential pattern of ossification in the vertebral column and thoracic cage in quail.