Location of the foramen ovale relative to the lateral pterygoid plate in adult computed tomography images.

OBJECTIVE

To uncover the positional relationship between the lateral pterygoid plate (LPP) and foramen ovale (FO) in an adult population.

METHODS

The 500 normal subjects (250 males and 250 females), who underwent cranial computed tomography scans were included into the study.

RESULTS

Four configurations regarding FO location types were determined: the lateral type in 347 sides (34.7%), medial type in 115 sides (11.5%), the direct type in 412 sides (41.2%), and the far type in 126 sides (12.6%). The frequencies of these types were affected by sex (p < 0.001), but not side (p = 417). The most common configuration was the direct type (47.4%) in females and the lateral type (41.8%) in males. The antero-posterior and medio-lateral diameters of FO were measured as 7.35 ± 1.98 mm and 4.08 ± 1.26 mm, respectively. The antero-posterior diameter was greater in the lateral type compared to the medial and direct types (p = 0.003). The medio-lateral diameter was greater in the lateral type compared to the direct type (p < 0.001). The pterygoalar and pterygospinous bars were observed in 24 sides (2.4%) and 18 sides (1.8%), respectively. The positional relationship between FO and LPP was statistically different between presence and absence of the pterygoalar bar (p = 0.001), but not between presence and absence of the pterygospinous bar (p = 0.512). In FOs with the pterygoalar bar, the far type was seen significantly less common.

CONCLUSIONS

The incidence of the far type was 12.6%; thus, a neurosurgeon can reach FO relatively easily by tracing the base of LPP backward in more than 80% of the population.