Frequency and characterization of the infratemporal spine in a sample of Chilean human skulls

The infratemporal spine, or sphenoidal tubercle, is a bony structure described in both classical anatomical literature and contemporary literature. However, the available literature does not mention the specific anatomical characteristics or the distribution of this bony element in the population. The aim of this study was to define this structure, identify its presence, and identify its morphology in a sample of Chilean human skulls. Fifty-seven dry skulls, obtained from the morphology unit at Universidad de los Andes, were used. The great wings of the sphenoid bone on both sides of the skull were evaluated in search of the infratemporal spine. These spines were classified according to their morphological characteristics of either laminar, pyramidal, or truncated pyramidal, as they related to the infratemporal crest and as they related to the pterygoid process. The presence of the infratemporal spine was found in 100 % of the studied skulls, unilaterally or bilaterally. The most common morphology was found to be laminar (40 %), followed by pyramidal (35 %), and, finally, truncated pyramidal (24 %). The majority (73 %) of these infratemporal spines was closely associated with the pterigoyd process with a complete or partial relation, with fewer (34 %) being associated with the infratemporal crest.