Bilateral Duplication of the Foramen Spinosum: A Case Report with Clinical and Developmental Implications

Abstract

In humans, the foramen spinosum (FS) is located within the sphenoid bone and transmits the middle meningeal artery (MMA). In species that evolutionarily predate humans, the FS exists within the temporal bone, the sphenosquamosal suture, or is absent altogether. It is therefore thought that, during the course of human evolution, the ossification of the posterior aspect of the greater wing of the sphenoid progressively developed around the MMA. The report documents the occurrence of a bilateral duplication of the FS in a male human skull. The report also discusses the clinical and developmental/anthropological significance. Because the foramen spinosum is utilized as a landmark for various surgical procedures involving the middle cranial fossa, the bilateral duplication of the foramen may be disorienting to the surgeon. Similarly, the dynamics of blood flow may be altered due to the bilateral bifurcation of the MMA. Because of the developmental significance of the FS, the occurrence of a bilateral duplication also has important anthropological implications.

Absence and Duplicate Foramen Spinosum in the Same Patient: An Extremely Rare Variation

“…5 In the literature, variations such as absence, small size, or duplication of the foramen spinosum have been reported to be rare. [7][8][9] Khan et al 7 reported that the foramen spinosum was absent in 0.4% of cases and stated that the middle meningeal artery may arise from the ophthalmic artery in these cases. In rare cases, the foramen spinosum may be small.…”

“…6 Previous studies have reported absence, small size and/or duplication of the foramen spinosum is rarely seen. [7][8][9] This study aims to report a case with duplicated foramen spinosum on one side and absent foramen spinosum on the other side and discuss the possible clinical implications of this variation.…”

“…Moreover, this foramen can also be used for middle meningeal artery ligation 6 . Previous studies have reported absence, small size and/or duplication of the foramen spinosum is rarely seen 7–9 …”

Morphometric Evaluation of Foramen spinosum

“…FS sphenoid kemiğin ala major bölgesinde yer alan, fossa crani media ile fossa infratemporalis arasındaki bağlantıyı sağlayan yapılardan bir tanesidir 3 . Duplike olması, unilateral veya bilateral eksikliği, gibi varyasyonlarının yanı sıra bilateral simetri durumu, uzunluğu, genişliği, alanı ve çevresi gibi parametreler de oldukça önemlidir 7 . Çünkü FS'nin morfolojisi ve morfometrik yapısı ile içinden geçen MMA arasında bir ilişki vardır 3 .…”

Angular Relationship Between the Foramen Ovale and the Trigeminal Impression

“…40,41 A line was drawn through the basilar process of the occiput to identify the midsagittal plane in order to orient the digital image appropriately for measurement with ImageJ software. 42,43 …”