Posterior ethmoid cell expansion towards the inferolateral region of the sphenoid sinus: a computed tomography study.
OBJECTIVE
The aim of this study was to investigate the anatomical imaging characteristics of posterior ethmoid cells (PEs) expanding towards the inferolateral region of the sphenoid sinus (SS).


METHODS
This study included a total of 278 inpatients (556 sides) whose paranasal sinus computed tomography (CT) scans were reviewed and collected from May 2018 to February 2019. The anatomical imaging characteristics of PEs expanding towards the inferolateral region of the SS were observed.


RESULTS
PEs expanding towards the inferolateral region of the SS formed an inferolateral spheno-ethmoid cell (ISEC). ISECs were observed on three sides (0.54%; 3/556) in three cases (1.08%; 3/278). All of the ISECs were present unilaterally on the right side of the SS. The ISECs originated from the most posterior ethmoid cell; they were first located at the medial aspect of the orbital apex, pneumatized continually backward to the inferomedial wall of the orbital apex, and then extended into the lateral region of the SS. The ISECs further extended laterally, inferiorly and posteriorly beyond the sphenoid body into the greater wing and/or pterygoid process.


CONCLUSION
An ISEC is a rare variation of ethmoid air cells. Preoperative recognition of ISECs is essential to achieve safe and effective endoscopic sinus surgery because of the important anatomical location.
['Liu|Jinfeng|J|http://orcid.org/0000-0002-9537-6603', 'Liu|Qitong|Q|', 'Wang|Ningyu|N|']
D000293:Adolescent D000328:Adult D000368:Aged D063405:Anatomic Variation D005005:Ethmoid Sinus D005260:Female D006801:Humans D008297:Male D008875:Middle Aged D012189:Retrospective Studies D013101:Sphenoid Sinus D014057:Tomography, X-Ray Computed D055815:Young Adult
Sphenoid sinus Computed Tomography Anatomic variation Ethmoid sinus X-ray