Migration of craniofacial periosteum in growing guinea-pigs.

The use of a carbon particle tattoo provided stable periosteal markers and a means of recording periosteal movement both anteroposteriorly and transversely during growth in guinea-pigs. In general, the periosteum migrated toward the cranial sutures. The radial pattern, demonstrated on the frontal bones and indicated on the nasal and parietal bones, showed that a periosteal envelope is identifiable with each bone. The area of origin of this centrifugal pattern of migration coincided with the ossification centre of that bone. Trabeculae and vascular canals tended to point in the direction of periosteal migration. The anteroposterior periosteal migration was proportional to but less than the anteroposterior growth of the craniofacial bones studied. The absolute medial periosteal marker migration, similar on the frontal and parietal bones, was directed in the opposite direction from the slight transverse bone growth. This may indicate a biophysical response to tension on the fibrous periosteum from the principally anteroposterior craniofacial growth. The amount of growth at the frontonasal, coronal and midline sutures diminished from anterior to posterior. The observed histological and morphological sutural characteristics concurred with these growth changes which correlate with the decreased cranial and increased facial growth during the age period studied. Although the fibrous periosteum is continuous over the separate membranous bones its behaviour appears to be intimately related to the growth of the craniofacial bones which it covers. The blending of the fibrous periosteum within the transverse sutures may prevent significant migration across craniofacial bones. It seems that the observed migratory patterns result from a close association of the fibrous periosteum with each growing craniofacial bone. The relationship of the fibrous periosteum to the growth of the craniofacial bones is a question requiring further investigation.