The literature data on the incidence of pneumatization of the crista galli based on patients’ computed tomography (CT) scans ranges from 3 to 37.5%. This study investigated for the first time the incidence of crista galli pneumatization based on CTscans of human skulls. The study examined 102 randomly selected human skulls (≥20 years of age; 76 males, 26 females). Skulls were scanned in a fixed position using cone beam computed tomography (CBCT) with a field of view of 145 × 130 mm and an isotropic voxel size of 0.25 mm. The scans were recorded in Digital Images and Communications in Medicine format. The CBCT images were analyzed using OnDemand3DTM software. A 2-mm contiguous slice thickness was used in the axial and coronal
planes. The width, length, and height (cranial-caudal dimension) of the pneumatized space within the crista galli were measured. The crista galli was found to be pneumatized in even 68 (66.6%) of the 102 skulls. Two types of pneumatized crista galli (PCG) were identified: PCG alone (surrounded by bony walls) and PCG + spongiosis (surrounded by spongy bone). Of the 68 pneumatized skulls, 31 were PCG alone (45.58%) and 37 were PCG + spongiosis (54.42%). The pneumatized regions had a width of 0.9–6.6 mm, length of 2.8–12.9 mm, and height of 3.6–17.1 mm. No statistically significant differences have been found regarding the sex and age. Regarding the proportions of pneumatization, the three types of crista galli have been determined resulting in new, practical classification: type S (small), typeM (moderate), and type L (large). The crista galli is not always a compact bone; in some cases, it is filled with spongy bone or pneumatized. In respect of proportions of pneumatization, there are three types of pneumatized crista galli: small, moderate, and large. Pneumatized crista galli can play an important role in clinical work, both as an inflamed sinus or other pathologies (sinusitis cristae galli, mucocoelae) or as a morphologic barrier in neurosurgical approaches to some tumors of the anterior skull base.