Crista galli pneumatization is an extension of the adjacent frontal sinuses

Abstract

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.

Fig 1.

A, Coronal CT scan of the paranasal sinuses in a 45-year-old women with difficulty breathing shows the typical appearance of crista galli pneumatization (arrow). B, Axial CT scan of the paranasal sinuses in a 51-year-old man with sinus pain shows extensive pneumatization of the crista galli from the right frontal sinus (arrow). C, Axial CT scan of the paranasal sinuses in a 63-year-old man with difficulty breathing shows extensive pneumatization of the crista galli from the left frontal sinus (arrow). D, Axial CT scan of the paranasal sinuses in a 33-year-old woman with difficulty breathing shows minimal pneumatization of the anterior crista galli from the left frontal sinus (arrow).

Fig 2.

A, Axial CT scan of the paranasal sinuses in a 27-year-old man with sinus pain shows polypoid mucosal thickening extending from the right frontal sinus into a well-pneumatized crista galli (arrow). B, Axial CT scan of the paranasal sinuses in a 49-year-old woman with sinus pain shows extensive mucosal thickening extending from the right frontal sinus into a well-pneumatized crista galli (arrow). There is also mucosal disease in the left frontal sinus.