Characterization and implications of the lingual process of the sphenoid bone: a cadaveric and radiographic study

Background: The surgical significance of the lingual process of the sphenoid bone (LPSB) has not been sufficiently addressed. The purpose of this study was to describe the anatomical details of the LPSB in relation to the quadrangular space. Moreover, the incidence of the LPSB and its correlation with the pneumatization of the sphenoid sinus and the development of the lateral recess of the sphenoid sinus (LRSS) were also evaluated. Methods: A dissection and exposure of the LPSB and the quadrangular space was performed on 10 cadaveric specimens (20 sides). The incidence, length, and height of the LPSB were also assessed on computed tomography (CT) images (60 patients, 120 sides). The association between the presence of the LPSB with the pneumatization type of the sphenoid sinus and the presence of a LRSS was evaluated. Results: In a cadaveric model, the LPSB, in association with the petrolingual ligament extending from the LPSB to the petrous apex, was identified on 7 sides (35%). The LPSB was continuous with the mandibular strut. The overall incidence of a LPSB was 48.33% on CT images, and the average length and height of the LPSB was (mean ± standard deviation) 5.30 ± 1.44 mm and 6.51 ± 1.32 mm, respectively. A significant correlation was identified between presence of the LPSB with the pneumatization type of the sphenoid sinus (p = 0.004) but no correlation was identified with the presence of the LRSS (p = 0.071). Conclusion: The LPSB and the petrolingual ligament are useful landmarks for procedures in the quadrangular space and Meckel's cave. However, the LPSB is not consistently present.