Anatomical Study and Classification of Foramina of the Squamous Part of the Temporal Bone

Abstract

The postglenoid foramen (PGF) is a rarely reported anatomical variant of the temporal bone, with limited data on its morphology, prevalence, and clinical relevance, particularly in non-European populations. This study aimed to investigate the anatomy and frequency of foramina located on the squamous part of the temporal bone, including the PGF, and to propose a classification system based on their anatomical positions. A total of 117 human skulls (234 sides), including both dried and Thiel-embalmed specimens, were examined through gross observation, cadaveric dissection, and computed tomography (CT) in selected cases. Foramina were localized relative to the postglenoid process (PGP) and zygomatic arch, and classified accordingly. Foramina were identified in 48 skulls (41.0%) and 67 sides (28.6%), with no significant difference between left and right sides (p = 1.00). Based on anatomical location, three main types were identified: preglenoid (76.7%), postglenoid (6.8%), and supra-arcuate (16.4%). Three foramina were found to communicate with the middle cranial fossa, confirmed by CT imaging. The proposed classification provides a practical framework for describing their positional variation. These findings are of clinical importance, particularly in surgical planning and radiologic interpretation, as such foramina may serve as conduits for venous communication or infection. Further studies are warranted to explore their histological structure and developmental origins.