Abstract The periosteal lymphatics of the mandible have long been considered an important route by which metastases from intraoral carcinoma spread to the cervical areas. Serial sections of the mandibular periosteum removed from surgical specimens were studied. The periosteum was involved only in those patients in which the tumor rested against the mandible. In instances in which there were only a few millimeters of normal tissue between the lesion and the mandible, there was no periosteal involvement. No relationship existed between the size of the lesion and the presence of periosteal involvement. There was no relationship between periosteal involvement and the presence or absence of cervical metastases. The distance between the lesion and the mandible appeared to be the decisive factor relative to involvement of the periosteum by tumor. Additional studies are under way.