Crista galli pneumatization is an extension of the adjacent frontal sinuses.

BACKGROUND AND PURPOSE The crista galli is part of the ethmoid bone and, as such, it could be expected that aeration of the crista would come from ethmoid cells. After observing crista pneumatization from the frontal sinuses in several cases, we undertook this study to establish how often crista galli pneumatization came from the frontal sinuses rather than from the ethmoid complex. MATERIALS AND METHODS Two hundred consecutive CT scans of the paranasal sinuses were studied in adult patients to obtain the incidence of crista galli pneumatization and the cell of origin for this phenomenon. A second group of 132 children, 0-7 years of age, was studied to see if any crista galli pneumatization occurred before frontal sinus development. A third group of 79 children, 7-12 years of age, was also studied to see when crista pneumatization occurred in children whose frontal sinuses had already extended into the squamosal portion of the frontal bone. RESULTS Of the 200 adult cases, there were 26 patients (13%) with crista galli pneumatization, all from either the left or right frontal sinuses. In the second group of children 0-7 years of age, there were no cases of crista pneumatization. In the third group of children 7-12 years of age, there were 4 cases of crista galli pneumatization, all from well-developed frontal sinuses. CONCLUSIONS Our study indicates that crista galli pneumatization is virtually exclusively from either the left or right frontal sinuses and not from displaced ethmoid complex cells in the frontal recess. This finding may have surgical implications when disease is present in the crista galli.