The periosteum is a vascular membrane that consists of a fibrous layer and a cellular cambium layer. It gets less osteogenic with age.33,34 Interestingly, its osteogenic potential seems to be dependent on the type of bone (membranous or enchondral) being covered.35,36 Speculatively, the passive nature of the periosteum does not produce very much tension or pressure on an onlay graft. In contrast, a more or less continuously moving muscle must exert an intermittent stress, which should negatively affect graft size. However, to what extent this muscle activity will affect the integration per se is not known. LaTrenta et al7 emphasized the importance of 2 factors, apart from the physiologic stress placed on the graft, that affect the extent of bone graft resorption (and integration): the vascularity of the host bed and the recipient-to-host bone contact. The recipient-to-host bone contact was presumably identical with both graft positionings, while the extent of revascularization may have been different. As theorized by Ermis and Poole,20 the increase in vascularity noted for submuscularly placed grafts may promote rapid and optimal graft incorporation. The graft resorption induced by stress implies that relatively larger grafts should be used when they are being placed below muscle, rather than subperiosteally positioned, to acquire the desired graft volume.