PURPOSE: Cranial bones receive a dual blood supply from extracranial and intracranial source vessels. Although the vascularization of the scalp and soft tissues based on these vessels is well known, there is little published data on the contribution and osseous territories of each artery. The terminal branches of the external carotid artery (ECA) all supply blood to the cranial vault. The aim of this study was to establish the contribution of the maxillary artery to vascularization of calvaria and define its vascular territory.
METHODS: The left ECA was isolated in 5 cadavers. All terminal branches of the ECA were ligated except for the maxillary artery. In all but one of the cadavers, the middle meningeal was also ligated. Hundred milliliters of lead oxide gel (65g lead oxide/3g powdered gelatin (Sigma-Aldrich, St. Louis Missouri) in warmed (70°C) normal saline) were injected in a pulsatile fashion until contrast was identified in the conjunctival vessels. Computed tomographic scans (Siemens Somatom Definition AS; Siemens Healthineers, Malvern, PA) of the heads were obtained (slice thickness, 1.0 mm). The homolateral and contralateral calvarial bones were evaluated by determining the percentage of number of CT slices that showed presence of contrast in the diploic space or the periosteal supply and the total number of slices representing each calvarial bone. The soft tissues were dissected to show the course of the branches of maxillary artery that were supplying the cranial vault. The distribution of the nutrient vessels and anastomotic arterial connections were identified. The periosteal territory of the deep temporal vessels was mapped and compared to the surface area of the temporal bone. Data are presented as means±standard deviation. Mann Whitney U tests were used to compare the presence of contrast in the diploic space vs periosteum in each bone.
RESULTS: Maxillary artery showed diffuse periosteal blood supply to the temporal, frontal, and sphenoid bones of the cranial vault. The anterior and posterior deep temporal arteries were codominant in vascularization of the temporal bone. Significant differences were found between the diploic and periosteal territories of the all homolateral cranial vault bones. Significant differences were found in all contralateral cranial vault bones except the temporal bone. The homolateral temporal bone had 100% periosteal vascularization, along with the sphenoid. The average area of the temporal bone supplied by the maxillary artery was 36%±12%. There were an average of 1.5 nutrient foramina communicating with the intracranial system per specimen.
CONCLUSION: The periosteal supply to the cranial vault is more robust than the endosteal blood supply. Maxillary artery consistently supplies the periosteum of the temporal, frontal and sphenoid bones.