Figure 1. Schematic diagrams of facial sutures under study and their typical levels of interdigitation. (A) Lateral view of the rabbit skull. MI = the maxillary incisor. PMS: the pre-maxillomaxillary suture. NFS: the nasofrontal suture. ZTS: the zygomaticotemporal suture. Different degrees of sutural interdigitation of the PMS (B), NFS (C), and ZTS (D) are confirmed by quantitative measurements of sutural interdigitation (Table). (B) ZTS diagram showing a typical straight-edge suture. (C) NFS diagram showing a moderately interdigitating suture. (D) PMS diagram showing a highly interdigitating suture. Two dots across each suture represent the locations of nano-indentation in the suture and sutural mineralization front.