Cranial synostosis and intra-uterine compression: a developmental study of human sutures.

The following hypothetical statements can be made. 1) Increased intra-uterine compression of the human cranium during the third trimester appears to produce sagittal synostosis by irreversibly altering the still immature sutural tissue that separates the parietal bones. 2) Intra-uterine compression does not cause facial sutures to fuse because they are physically shielded by the larger neurocranium and their ligaments are sufficiently mature to survive a chronic compressive force. 3) Postnatal compression of cranial and facial sutures normally does not result in bony fusion because their vascularized, differentiated, mature ligaments are capable of repair and regeneration.