Unpublished findings in the parasellar dura mater of canines: description of the petroclinoid and interclinoid ligaments

Abstract

At the base of the cranial cavity, the parasellar compartment contains a series of complex anatomical structures that are closely related in a small area, with the cavernous sinus serving as a reference point. In veterinary medicine, the lack of anatomical descriptions represents a deficiency in the modern literature, which makes this area an underexplored one by neurologists, surgeons, and ophthalmologists. The sellar diaphragm, a structure of the dura mater that separates the pituitary gland from the diencephalon, extends laterally into the parasellar region, forming the dorsal limit or roof of the cavernous sinus and interacts with the vascular and nerve structures traversing the middle cranial fossa.

The objective of this study is to provide an anatomical description of the fibrous structures formed by the parasellar dura mater in this region. Dissections were performed and analyzed on 20 adult canine heads of various morphological configurations, preserved in formalin, and using neurosurgical instruments. In relation to the dura mater forming the roof of the cavernous sinus, the oculomotor and trochlear nerves are located. Upon their removal, a triangular area was identified, delineated by three fibrous thickening structures: two extending from the apex of the temporal bone towards the rostral and caudal clinoid processes, and a third positioned in the transverse axis between both clinoid processes. These thickening bands of dura mater were identified in all studied preparations. The increasingly necessary interdisciplinary management frameworks requires an intensified study of the parasellar region and the incorporation of the corresponding anatomical nomenclature, allowing for the development of procedures associated with managing its pathologies.

The consistency observed in dissections supports our proposal to name the identified fibrous structures as: rostral petroclinoid ligament, caudal petroclinoid ligament, and interclinoid ligament. A detailed description of the anatomy of the cavernous sinus, its boundaries, and relationships is essential for planning an organized approach to the comprehensive management of its lesions.