Regenerative therapies are commonly needed prior to implant placement in the posterior maxilla following tooth extraction. The aim of this study was to investigate the anatomical features of the atrophic posterior maxilla that might affect surgical approach selection and technique and risk of intra- and postoperative complications. Cone beam computed tomography files were screened to identify pristine atrophic maxillary ridges in need of bone augmentation (ridge height < 10 mm). Ridge height and width and lateral wall thickness (LWT) were measured at different levels, and palatonasal recess and lateral wall morphology were calculated. The influence of site was assessed using generalized estimation equations. The linear correlation between parameters was estimated with Pearson coefficient, and principal component analysis (PCA) was performed to establish patterns of multiple correlations. In the 433 edentulous sites and 6,062 measurements analyzed, the strongest correlations corresponded to LWT measurements at the different levels. Most of the parameters examined presented linearity (P < .001), allowing establishment of four main morphologic patterns according to anatomical features. The anatomical structures of the atrophic posterior maxilla follow linear patterns that might predict complications due to an anatomical feature and thus success in regenerative therapy.